Publications

  • 100-year lower mississippi floods in a global climate model: Characteristics and future changes

    K. Van Der Wiel; S. B. Kapnick; G. A. Vecchi; J. A. Smith; P. C.D. Milly; L. Jia
    Journal Article

    Floods in the Mississippi basin can have large negative societal, natural, and economic impacts. Understanding the drivers of floods, now and in the future, is relevant for risk management and infrastructureplanning purposes. We investigate the drivers of 100-yr-return lower Mississippi River floods using a global coupled climate model with an...

  • The 3- 4-week MJO prediction skill in a GFDL coupled model

    B. Xiang; M. Zhao; X. Jiang; S.-J. Lin; T. Li; X. Fu; G. A. Vecchi
    Journal Article

    Based on a new version of the Geophysical Fluid Dynamics Laboratory (GFDL) coupled model, the Madden- Julian oscillation (MJO) prediction skill in boreal wintertime (November- April) is evaluated by analyzing 11 years (2003- 13) of hindcast experiments. The initial conditions are obtained by applying a simple nudging technique toward...

  • The added value of IMERG in characterizing rainfall in tropical cyclones

    M. F.Rios Gaona; G. Villarini; W. Zhang; G. Vecchi
    Journal Article

    Heavy rainfall associated with landfalling tropical cyclones (TCs) is responsible for significant societal and economic impacts. Improved characterization and description of how rainfall during these storms changes as a function of distance from the center of circulation are critical to increase our preparedness against this natural hazard....

  • Application of the Cyclone Phase Space to Extratropical Transition in a Global Climate Model

    M. Bieli; A. H. Sobel; S. J. Camargo; H. Murakami; G. A. Vecchi
    Journal Article

    The authors analyze the global statistics of tropical cyclones undergoing extratropical transition (ET) in the Forecast‐oriented Low Ocean Resolution version of CM2.5 with Flux Adjustment (FLOR‐FA). The cyclone phase space (CPS) is used to diagnose ET. A simulation of the recent historical climate is analyzed and compared with data from the...

  • Assessing GFDL high-resolution climate model water and energy budgets from AMIP simulations over Africa

    D. Tian; L. Jia; G. A. Vecchi; E. F. Wood; M. Pan
    Journal Article

    This study assessed surface water and energy budgets in Atmospheric Model Intercomparison Project (AMIP) simulations of a coupled atmosphere-land model developed by Geophysical Fluid Dynamics Laboratory (Atmospheric General Circulation Model (AM2.5)). The AM2.5 water and energy budget variables were compared with four reanalyses data sets and...

  • Assessing the influence of climate on wintertime SARS-CoV-2 outbreaks

    Rachel E. Baker; Wenchang Yang; Gabriel A. Vecchi; Jessica E. Metcalf; Bryan T. Grenfell
    Journal Article

    High susceptibility has limited the role of climate in the SARS-CoV-2 pandemic to date.However, understanding a possible future effect of climate, as susceptibility declines and thenorthern-hemisphere winter approaches, is an important open question. Here we use anepidemiological model, constrained by observations, to assess the sensitivity of...

  • Assessing the influence of climate on wintertime SARS-CoV-2 outbreaks

    Rachel E. Baker; Wenchang Yang; Gabriel A. Vecchi; Jessica E. Metcalf; Bryan T. Grenfell
    Journal Article

    High susceptibility has limited the role of climate in the SARS-CoV-2 pandemic to date.However, understanding a possible future effect of climate, as susceptibility declines and thenorthern-hemisphere winter approaches, is an important open question. Here we use anepidemiological model, constrained by observations, to assess the sensitivity of...

  • An assessment of multimodel simulations for the variability of Western North Pacific tropical cyclones and its association with ENSO

    R. Han; H. Wang; Z. Z. Hu; A. Kumar; W. Li; L. N. Long; J. E. Schemm; P. Peng; W. Wang; D. Si; X. Jia; M. Zhao; G. A. Vecchi; T. E. LaRow; Y. K. Lim; S. D. Schubert; S. J. Camargo; N. Henderson; J. A. Jonas; K. J.E. Walsh
    Journal Article

    An assessment of simulations of the interannual variability of tropical cyclones (TCs) over the western North Pacific (WNP) and its association with El Niño-Southern Oscillation (ENSO), as well as a subsequent diagnosis for possible causes of model biases generated from simulated large-scale climate conditions, are documented in the paper. The...

  • Assessment of summer rainfall forecast skill in the Intra-Americas in GFDL high and low-resolution models

    L. Krishnamurthy; Á.G. Muñoz; G. A. Vecchi; R. Msadek; A. T. Wittenberg; B. Stern; R. Gudgel; F. Zeng
    Journal Article

    The Caribbean low-level jet (CLLJ) is an important component of the atmospheric circulation over the Intra-Americas Sea (IAS) which impacts the weather and climate both locally and remotely. It influences the rainfall variability in the Caribbean, Central America, northern South America, the tropical Pacific and the continental Unites States...

  • Assessment of summer rainfall forecast skill in the Intra-Americas in GFDL high and low-resolution models

    L. Krishnamurthy; A. G. Munoz; G. A. Vecchi; R. Msadek; A. T. Wittenberg; B. Stern; R. Gudgel; F. Zeng
    Journal Article

    2018 The Author(s) The Caribbean low-level jet (CLLJ) is an important component of the atmospheric circulation over the Intra-Americas Sea (IAS) which impacts the weather and climate both locally and remotely. It influences the rainfall variability in the Caribbean, Central America, northern South America, the tropical Pacific and the...

  • An asymmetric rainfall response to ENSO in East Asia

    C.H.J. Ng; G. A. Vecchi; Á.G. Muñoz; H. Murakami
    Journal Article

    This study explores the impact of El Niño and La Niña events on precipitation and circulation in East Asia. The results are based on statistical analysis of various observational datasets and Geophysical Fluid Dynamics Laboratory’s (GFDL’s) global climate model experiments. Multiple observational datasets and certain models show that in the...

  • Attribution of extreme rainfall from Hurricane Harvey, August 2017

    G. J. Van Oldenborgh; K. Van Der Wiel; A. Sebastian; R. Singh; J. Arrighi; F. Otto; K. Haustein; S. Li; G. A. Vecchi; H. Cullen
    Journal Article

    uring August 25-30, 2017, Hurricane Harvey stalled over Texas and caused extreme precipitation, particularly over Houston and the surrounding area on August 26-28. This resulted in extensive flooding with over 80 fatalities and large economic costs. It was an extremely rare event: the return period of the highest observed three-day...

  • Attribution of the impacts of the 2008 flooding in Cedar Rapids (Iowa) to anthropogenic forcing

    G. Villarini; W. Zhang; F. Quintero; W. F. Krajewski; G..A. Vecchi
    Journal Article

    The City of Cedar Rapids was significantly affected by the June 2008 flood. However, little is known about the role anthropogenic warming during this event, not only in terms of hydrologic response but also of impacts. Here we use a continuous distributed hydrologic model forced with precipitation with and without external forcing and show that...

  • Author Correction: Recent increases in tropical cyclone intensification rates

    K. T. Bhatia; G. A. Vecchi; T.R. Knutson; H. Murakami; J. Kossin; K W. Dixon; C. E. Whitlock
    Journal Article

    The original version of this Article contained an error in the second sentence of the first paragraph of the ‘Quantile mapping’ section of the Methods, which incorrectly read ‘We primarily focus on results produced using an additive version of QDM26 by making use of R programming language code contained in the CRAN MBC package version 0.10–...

  • Basin patterns of global sea level changes for 2004–2007

    You-Soon Chang; Anthony J. Rosati; Gabriel A. Vecchi
    Journal Article

    Based on independent observations, we estimate the sea level budget and linear trends for individual ocean basins and the world ocean during 2004–2007. Even though it is confirmed that the seasonal variation of global sea level is balanced by the different sea level components (total sea level change from satellite altimetry equals to the sum...

  • Beyond weather time-scale prediction for hurricane sandy and super typhoon haiyan in a global climate model

    B. Xiang; S. J. Lin; M. Zhao; S. Zhang; G. A. Vecchi; T. Li; X. Jiang; L. Harris
    Journal Article

    While tropical cyclone (TC) prediction, in particular TC genesis, remains very challenging, accurate prediction of TCs is critical for timely preparedness and mitigation. Using a new version of the Geophysical Fluid Dynamics Laboratory (GFDL) coupled model, the authors studied the predictability of two destructive landfall TCs: Hurricane Sandy...

  • Biases in the atlantic ITCZ in seasonal-interannual variations for a coarse- and a high-resolution coupled climate model

    T. Doi; G. A. Vecchi; A. J. Rosati; T. L. Delworth
    Journal Article

    Using two fully coupled ocean-atmosphere models-Climate Model version 2.1 (CM2.1), developed at the Geophysical Fluid Dynamics Laboratory, and Climate Model version 2.5 (CM2.5), a new high-resolution climate model based on CM2.1-the characteristics and sources of SST and precipitation biases associated with the Atlantic ITCZ have been...

  • Causes and probability of occurrence of extreme precipitation events like Chennai 2015

    L. Krishnamurthy; G. A. Vecchi; X. Yang; K. Van Der Wiel; V. Balaji; S. B. Kapnick; L. Jia; F. Zeng; K. Paffendorf; S. Underwood
    Journal Article

    © 2018 American Meteorological Society. Unprecedented high-intensity flooding induced by extreme precipitation was reported over Chennai in India during November-December of 2015, which led to extensive damage to human life and property. It is of utmost importance to determine the odds of occurrence of such extreme floods in the future, and the...

  • Central equatorial Pacific zonal currents. II: The seasonal cycle and the boreal spring surface eastward surge

    D. E. Harrison; R. D. Romea; G. A. Vecchi
    Journal Article

    The seasonally averaged zonal momentum equation tendencies at 140W are studied in a high-resolution primitive equation ocean general circulation model simulation of the tropical Pacific. The model experiment, forced by climatological monthly average wind-stress, reproduces well the observed boreal springtime eastward surge of the normally...

  • Characteristics of model tropical cyclone climatology and the large-scale environment

    S. Camargo; C. F. Giulivi; A. H. Sobel; A. A. Wing; D. Kim; Y. Moon; J. D.O. Strong; A. D. Del Genio; M. Kelley; H. Murakami; K. A. Reed; E. Scoccimarro; G. Vecchi; M. F. Wehner; Zarzycki; M. Zhao
    Journal Article

    Here we explore the relationship between the global climatological characteristics of tropical cyclones (TCs) in climate models and the modeled large-scale environment across a large number of models. We consider the climatology of TCs in 30 climate models with a wide range of horizontal resolutions. We examine if there is a systematic...

  • Characterization of rainfall distribution and flooding associated with U.S. landfalling tropical cyclones: Analyses of Hurricanes Frances, Ivan, and Jeanne (2004)

    G. Villarini; J. A. Smith; M. L. Baeck; T. Marchok; G. A. Vecchi
    Journal Article

    [1] Rainfall and flooding associated with landfalling tropical cyclones are examined through empirical analyses of three hurricanes (Frances, Ivan, and Jeanne) that affected large portions of the eastern U.S. during September 2004. Three rainfall products are considered for the analyses: NLDAS, Stage IV, and TMPA. Each of these products has...

  • Climate Impacts From Large Volcanic Eruptions in a High-Resolution Climate Model: The Importance of Forcing Structure

    Wenchang Yang; Gabriel A. Vecchi; Stephan Fueglistaler; Larry W. Horowitz; David J. Luet; Ángel G. Muñoz; David Paynter; Seth Underwood
    Journal Article

    Abstract Explosivevolcanic eruptions have large climate impacts and can serve as observable tests of the climatic response to radiative forcing. Using a high-resolution climate model, we contrast the climate responses to Pinatubo, with symmetric forcing, and those to Santa Maria and Agung, which had meridionally asymmetric forcing. Although...

  • Climate Response of the Equatorial Pacific to Global Warming

    Pedro N. DiNezio; Amy C. Clement; Gabriel A. Vecchi; Brian J. Soden; Benjamin P. Kirtman; Sang-Ki Lee
    Journal Article

    The climate response of the equatorial Pacific to increased greenhouse gases is investigated using numerical experiments from 11 climate models participating in the Intergovernmental Panel on Climate Change?s Fourth Assessment Report. Multimodel mean climate responses to CO2 doubling are identified and related to changes in the heat budget of...

  • Climate science: Origins of Atlantic decadal swings

    G. A. Vecchi; T. L. Delworth; B. Booth
    Journal Article

    The topic in brief

    Atlantic multidecadal variability (AMV) describes alternating swings in sea surface temperature in the North Atlantic Ocean that occur with a characteristic timescale of several decades (Fig. 1).

    Such temperature changes have been...

  • The Climatological Effect of Saharan Dust on Global Tropical Cyclones in a Fully Coupled GCM

    J. D.O. . Strong; G. A. Vecchi; P. Ginoux
    Journal Article

    Climate in the tropical North Atlantic and West Africa is known to be sensitive to both the atmospheric burden and optical properties of aerosolized mineral dust. We investigate the global climatic response to an idealized perturbation in atmospheric burden of Saharan-born mineral dust, comparable to the observed changes between the 1960s and...

  • Climatological, virological and sociological drivers of current and projected dengue fever outbreak dynamics in Sri Lanka

    C. E. Wagner; M. Hooshyar; R. E. Baker; W. Yang; N. Arinaminpathy; G.A. Vecchi; C. J.E. Metcalf; A. Porporato; B. T. Grenfell
    Journal Article

    The largest ever Sri Lankan dengue outbreak of 2017 provides an opportunity for investigating the relative contributions of climatological, epidemiological and sociological drivers on the epidemic patterns of this clinically important vector-borne disease. To do so, we develop a climatologically driven disease transmission framework for dengue...

  • Comment on "Multiyear prediction of monthly mean atlantic meridional overturning circulation at 26.5°N"

    G. A. Vecchi; R. Msadek; T. L. Delworth; K.W. Discon; E. Guilyardi; E. Hawkins; A. R. Karspeck; J. Mignot; J. Robson; A. Rosati; R. Zhang
    Journal Article

    Matei et al. (Reports, 6 January 2012, p. 76) claim to show skillful multiyear predictions of the Atlantic Meridional Overturning Circulation (AMOC). However, these claims are not justified, primarily because the predictions of AMOC transport do not outperform simple reference forecasts based on climatological annual cycles. Accordingly, there...

  • Comment on 'Roles of interbasin frequency changes in the poleward shifts of the maximum intensity location of tropical cyclones'

  • Comparison of global objective analyzed T-S fields of the upper ocean for 2008-2011

    Y. S. Chang; G. A. Vecchi; A. Rosati; S. Zhang; X. Yang
    Journal Article

    There have been few attempts to quantify errors in various objective analyzed (OA) fields, even though they have potential uncertainties associated with data handling and mapping methods. Here, we compare five different OA fields (EN3, GFDL, IPRC, JAMSTEC, and SIO) for 2008-2011. The variability and linear trends of the upper ocean temperature...

  • Compensation between cloud feedback and aerosol-cloud interaction in CMIP6 models

    Chenggong Wang; Brian Soden; Wenchang Yang; Gabriel A. Vecchi
    Journal Article

    The most recent generation of climate models (the 6th Phase of the Coupled Model Intercomparison  Project – CMIP6) yields estimates of effective climate sensitivity (ECS) that are much higher than  past generations due to a stronger amplification from cloud feedback. If plausible, these models require substantially larger greenhouse gas...

  • Contrasting the termination of moderate and extreme El Niño events in coupled general circulation models

    Matthieu Lengaigne; Gabriel A. Vecchi
    Journal Article

    As in the observed record, the termination of El Niño in the coupled IPCC-AR4 climate models involves meridional processes tied to the seasonal cycle. These meridional processes both precondition the termination of El Niño events in general and lead to a peculiar termination of extreme El Niño events (such as those of 1982–83 and 1997–98), in...

  • Contribution of tropical cyclones to rainfall at the global scale

    A. Khouakhi; G. Villarini; G. A. Vecchi
    Journal Article

    This study quantifies the relative contribution of tropical cyclones (TCs) to annual, seasonal, and extreme rainfall and examines the connection between El Niño-Southern Oscillation (ENSO) and the occurrence of extreme TC-induced rainfall across the globe. The authors use historical 6-h best-track TC datasets and daily precipitation data from...

  • Correction to “Expansion of the Hadley cell under global warming”

    Jian Lu; Gabriel A. Vecchi; Thomas Reichler
    Journal Article
  • Corrigendum: Attribution of extreme rainfall from Hurricane Harvey, August 2017 (2017 Environ. Res. Lett. 12 124009)

    Geert Jan van Oldenborgh; Karin Van Der Wiel; Antonia Sebastian; Roop Singh; Julie Arrighi; Friederike Otto; Karsten Haustein; Sihan Li; Gabriel Vecchi; Heidi Cullen
    Journal Article
  • Corrigendum: The effective number of spatial degrees of freedom of a time-varying field

    G. A. Vecchi; R. Msadek; W. Anderson; Y.-S. Chang; T. Delworth; K. Dixon; R. Gudgel; A. Rosati; B. Stern; G. Villarini; A. Wittenberg; X. Yang; F. Zeng; R. Zhang; S. Zhang
    Journal Article

    In the original manuscript of Vecchi et al. (2013), Eq. (6), which is used to quantify the effective number of degrees of freedom in two autocorrelated time series Neff, was incorrectly transcribed from Bretherton et al. (1999). The correct equation is, where N is the number of samples in each time series, and rτX and rτY are the biased...

  • Could the recent zika epidemic have been predicted?

    A. G. Munoz; M. C. Thomson; A. M. Stewart-Ibarra; G. A. Vecchi; X. Chourio; P. Najera; Z. Moran; X. Yang
    Journal Article

    Given knowledge at the time, the recent 2015-2016 zika virus (ZIKV) epidemic probably could not have been predicted. Without the prior knowledge of ZIKV being already present in South America, and given the lack of understanding of key epidemiologic processes and long-term records of ZIKV cases in the continent, the best related prediction...

  • Decadal climate prediction an update from the trenches

    G. A. Meehl; L. Goddard; G. Boer; R. Burgman; G. Branstator; C. Cassou; S. Corti; G. Danabasoglu; F. Doblas-Reyes; E. Hawkins; A. Karspeck; M. Kimoto; A. Kumar; D. Matei; J. Mignot; R. Msadek; A. Navarra; H. Pohlmann; M. Rienecker; T. Rosati; E. Schneider; D. Smith; R. Sutton; H. Teng; G. J. Van Oldenborgh; G. Vecchi; S. Yeager
    Journal Article
  • Decadal temperature predictions over the continental United States: Analysis and Enhancement

    K. Salvi; G. Villarini; G. A. Vecchi; S. Chosh
    Journal Article
  • Detection, attribution, and projection of regional rainfall changes on (multi-) decadal time scales: A focus on southeastern South America

    H. Zhang; T. L. Delworth; F. Zeng; G.A. Vecchi; K. Paffendorf; L. Jia
    Journal Article

    Observed austral summertime (November through April) rainfall in southeastern South America (SESA)-including northern Argentina, Uruguay, southern Brazil, and Paraguay-has exhibited substantial low-frequency variations with a multidecadal moistening trend during the twentieth century and a subsequent decadal drying trend during the current...

  • The direct and ocean-mediated influence of Asian orography on tropical precipitation and cyclones

    J.W. Baldwin; G. A. Vecchi; S. Bordoni
    Journal Article

    Prior global climate model (GCM) experiments have shown that the Tibetan Plateau and related orography play a significant role in enhancing the Indian Monsoon, particularly during its onset, and the East Asian monsoon. However, these experiments have been largely performed with atmosphere-only, lower-resolution GCMs that neglect the influence...

  • Dominant Role of Atlantic Multidecadal Oscillation in the Recent Decadal Changes in Western North Pacific Tropical Cyclone Activity

    W. Zhang; G. A. Vecchi; H. Murakami; G. Villarini; T. L. Delworth; X. Yang; L. Jia
    Journal Article

    2017. American Geophysical Union. All Rights Reserved. Over the 1997–2014 period, the mean frequency of western North Pacific (WNP) tropical cyclones (TCs) was markedly lower (~18%) than the period 1980–1996. Here we show that these changes were driven by an intensification of the vertical wind shear in the southeastern/eastern WNP tied to the...

  • Dominant role of subtropical pacific warming in extreme Eastern Pacific hurricane seasons: 2015 and the future

    H. Murakami; G. A. Vecchi; T. L. Delworth; A. T. Wittenberg; S. Underwood; R. Gudgel; X. Yang; L. Jia; F. Zeng; K. Paffendorf; W. Zhang
    Journal Article

    The 2015 hurricane season in the eastern and central Pacific Ocean (EPO and CPO), particularly around Hawaii, was extremely active, including a record number of tropical cyclones (TCs) and the first instance of three simultaneous category-4 hurricanes in the EPO and CPO. A strong El Niño developed during the 2015 boreal summer season and was...

  • Dynamical downscaling projections of twenty-first-century atlantic hurricane activity: CMIP3 and CMIP5 model-based scenarios

    T.R. Knutson; J. J. Sirutis; G. A. Vecchi; S. Garner; M. Zhao; H. S. Kim; M. Bender; R. E. Tuleya; I. M. Held; G. Villarini
    Journal Article

    Twenty-first-century projections of Atlantic climate change are downscaled to explore the robustness of potential changes in hurricane activity. Multimodel ensembles using the phase 3 of the Coupled Model Intercomparison Project (CMIP3)/Special Report on Emissions Scenarios A1B (SRES A1B; late-twenty-first century) and phase 5 of the Coupled...

  • A dynamical statistical framework for seasonal streamflow forecasting in an agricultural watershed

    L. J. Slater; G. Villarini; A. A. Bradley; G. A. Vecchi
    Journal Article

    he state of Iowa in the US Midwest is regularly affected by major floods and has seen a notable increase in agricultural land cover over the twentieth century. We present a novel statistical-dynamical approach for probabilistic seasonal streamflow forecasting using land cover and General Circulation Model (GCM) precipitation forecasts. Low to...

  • The East Asian Subtropical Jet Stream and Atlantic Tropical Cyclones

    Wei Zhang; Gabriele Villarini; Gabriel A. Vecchi
    Journal Article

    Atlantic tropical cyclones (TCs) can cause significant societal and economic impacts, as 2019's Dorian serves to remind us of these storms' destructiveness. Decades of effort to understand and predict Atlantic TC activity have improved seasonal forecast skill, but large uncertainties still remain, in part due to an incomplete understanding of...

  • Eastward surface jets in the central equatorial Pacific, November 1991–March 1992

    D. E. Harrison; G. A. Vecchi; R. H. Weisberg
    Journal Article

    The central equatorial Pacific typically has westward surface and near-surface flow, interrupted by periods of eastward flow. The processes that may have been responsible for two periods of eastward flow during the 1991-92 El Niño between October 1991 and March 1992 are explored here, based on realistic hindcasts from a high-vertical resolution...

  • Effect of remote sea surface temperature change on tropical cyclone potential intensity

    Gabriel A. Vecchi; Brian J. Soden
    Journal Article

    The response of tropical cyclone activity to global warming is widely debated. It is often assumed that warmer sea surface temperatures provide a more favourable environment for the development and intensification of tropical cyclones, but cyclone genesis and intensity are also affected by the vertical thermodynamic properties of the atmosphere...

  • Effects of surface forcing on the seasonal cycle of the eastern equatorial Pacific

    D. E. Harrison; A. M. Chiodi; G. A. Vecchi
    Journal Article

    The roles of zonal and meridional wind stress and of surface heat flux in the seasonal cycle of sea surface temperature (SST) are examined with a primitive equation (PE) model of the tropical Pacific Ocean. While a variety of previous numerical and observational studies have examined the seasonal cycle of SST in the eastern tropical Pacific, it...

  • El Niño and La Niña—equatorial Pacific thermocline depth and sea surface temperature anomalies, 1986–98

    D. E. Harrison; Gabriel A. Vecchi
    Journal Article

    Simple models of the El Niño-Southern Oscillation (ENSO) phenomenon have provided many of our basic ideas about ENSO mechanisms. These models exhibit a range of correlation patterns between thermocline depth anomaly (Z20A) and sea surface temperature anomaly (SSTA). We use 13 years of Pacific equatorial waveguide observations to explore the...

  • El Niño and our future climate: where do we stand?

    Gabriel A. Vecchi; Andrew T. Wittenberg
    Journal Article

    El Niño and La Niña comprise the dominant mode of tropical climate variability: the El Niño and Southern Oscillation (ENSO) phenomenon. ENSO variations influence climate, ecosystems, and societies around the globe. It is, therefore, of great interest to understand the character of past and future ENSO variations. In this brief review, we...

  • Enhanced warming of the Northwest Atlantic Ocean under climate change

    V. S. Saba; S. M. Griffies; W. G. Anderson; M. Winton; M. A. Alexander; T. L. Delworth; J. A. Hare; M. J. Harrison; A. Rosati; G. A. Vecchi; R. Zhang
    Journal Article

    The Intergovernmental Panel on Climate Change (IPCC) fifth assessment of projected global and regional ocean temperature change is based on global climate models that have coarse (μ100 km) ocean and atmosphere resolutions. In the Northwest Atlantic, the ensemble of global climate models has a warm bias in sea surface temperature due to a...

  • ENSO and greenhouse warming

    W. Cai; A. Santoso; G. Wang; S. W. Yeh; S. I. An; K.M. Cobb; M. Collins; E. Guilyardi; F. F. Jin; J. S. Kug; M. Lengaigne; M. McPhaden; K. Takahashi; A. Timmermann; G. A. Vecchi; M. Watanabe; L. Wu
    Journal Article

    The El Niño/Southern Oscillation (ENSO) is the dominant climate phenomenon affecting extreme weather conditions worldwide. Its response to greenhouse warming has challenged scientists for decades, despite model agreement on projected changes in mean state. Recent studies have provided new insights into the elusive links between changes in ENSO...

  • Enso extremes and diversity : Dynamics, teleconnections, and impacts

    A. Santosa; W. Cai; M. Collins; M. McPhaden; F.-F. Jin; E. Guilyardi; G.A. Vecchi; D. Dommenget; G. Wang
    Journal Article
  • ENSO modulation: Is it decadally predictable?

    A. T. Wittenberg; A. Rosati; T. L. Delworth; G. A. Vecchi; F. Zeng
    Journal Article

    Observations and climate simulations exhibit epochs of extreme El Niño-Southern Oscillation (ENSO) behavior that can persist for decades. Previous studies have revealed a wide range of ENSO responses to forcings from greenhouse gases, aerosols, and orbital variations, but they have also shown that interdecadal modulation of ENSO can arise even...

  • ENSO transition, duration, and amplitude asymmetries: Role of the nonlinear wind stress coupling in a conceptual model

    K.-Y. Choi; G. A. Vecchi; A. T. Wittenberg
    Journal Article

    The El Niño-Southern Oscillation (ENSO) exhibits well-known asymmetries: 1) warm events are stronger than cold events, 2) strong warm events are more likely to be followed by cold events than vice versa, and 3) cold events are more persistent than warm events. Coupled GCM simulations, however, continue to underestimate many of these observed...

  • Epidemic dynamics of respiratory syncytial virus in current and future climates

    R. E. Baker; A. S. Mahmud; C. E. Wagner; W. Yang; V. E. Pitzer; C. Viboud; G. A. Vecchi; C. J.E. Metcalf; B. T. Grenfell
    Journal Article

    A key question for infectious disease dynamics is the impact of the climate on future burden.Here, we evaluate the climate drivers of respiratory syncytial virus (RSV), an importantdeterminant of disease in young children. We combine a dataset of county-level observationsfrom the US with state-level observations from Mexico, spanning much of...

  • Erratum: Hurricanes and climate: The U.S. Clivar working group on hurricanes (Bulletin of the American Meteorological Society (2015) 96 (997-1017)

    K. J.E. Walsh; S. J. Camargo; G. A. Vecchi; A. S. Daloz; J. Elsner; K. Emanuel; M. Horn; Y. K. Lim; M. Roberts; C. Patricola; E. Scoccimarro; A. H. Sobel; S. Strazzo; G. Villarini; M. Wehner; M. Zhao; J. P. Kossin; T. Larow; K. Oouchi; S. Schubert; H. Wang; J. Bacmeister; P. Chang; F. Chauvin
    Journal Article
  • Erratum: Simulated reduction in Atlantic hurricane frequency under twenty-first-century warming conditions

    Thomas Knutson; Joseph Sirutis; Stephen Garner; Gabriel Vecchi; Isaac Held
    Journal Article
  • On Estimates of Historical North Atlantic Tropical Cyclone Activity

    Gabriel A. Vecchi; Thomas R. Knutson
    Journal Article
    Abstract In this study, an estimate of the expected number of Atlantic tropical cyclones (TCs) that were missed by the observing system in the presatellite era (between 1878 and 1965) is developed. The significance of trends in both number and duration since 1878 is assessed and these results are related to estimated changes in sea surface...
  • Estimating Annual Numbers of Atlantic Hurricanes Missing from the HURDAT Database (1878–1965) Using Ship Track Density

    Gabriel A. Vecchi; Thomas R. Knutson
    Journal Article

    This study assesses the impact of imperfect sampling in the presatellite era (between 1878 and 1965) on North Atlantic hurricane activity measures and on the long-term trends in those measures. The results indicate that a substantial upward adjustment of hurricane counts may be needed prior to 1965 to account for likely ?missed? hurricanes due...

  • Estimating Convection Parameters in the GFDL CM2.1 Model Using Ensemble Data Assimilation

    S. Li; S. Zhang; Z. Liu; Lv Lu; J. Zhu; X Zhang; X. Wu; M. Zhao; G. A. Vecchi; R.-H. Zhang; X. Lin
    Journal Article

    © 2018. The Authors. Parametric uncertainty in convection parameterization is one major source of model errors that cause model climate drift. Convection parameter tuning has been widely studied in atmospheric models to help mitigate the problem. However, in a fully coupled general circulation model (CGCM), convection parameters which impact...

  • Estimating decadal predictability for the Southern Ocean using the GFDL CM2.1 model

    L. Zhang; T. L. Delworth; X. Yang; R. G. Gudgel; L. Jia; G. A. Vecchi; F. Zeng
    Journal Article

    This study explores the potential predictability of the Southern Ocean (SO) climate on decadal time scales as represented in the GFDL CM2.1 model using prognostic methods. Perfect model predictability experiments are conducted starting from 10 different initial states, showing potentially predictable variations of Antarctic bottom water (AABW)...

  • Estuarine forecasts at weather to subseasonal time scales

    Andrew C. Ross; Charles A. Stock; Deith W. Dixon; Majorie A.M. Friedrichs; Raleigh R. Hood; Ming Li; Kathleen Pegion; Vincent Saba; Gabriel A. Vecchi
    Journal Article

    Most present forecast systems for estuaries predict conditions for only a few days into the future. However, there are many reasons to expect that skillful estuarine forecasts are possible for longer time periods, including increasingly skillful extended atmospheric forecasts, the potential for lasting impacts of atmospheric forcing on...

  • Evaluation of tropical Pacific observing systems using NCEP and GFDL ocean data assimilation systems

    Y. Xue; C. Wen; X. Yang; D. Behringer; A. Kumar; G. Vecchi; A. Rosati; R. Gudgel
    Journal Article

    The TAO/TRITON array is the cornerstone of the tropical Pacific and ENSO observing system. Motivated by the recent rapid decline of the TAO/TRITON array, the potential utility of TAO/TRITON was assessed for ENSO monitoring and prediction. The analysis focused on the period when observations from Argo floats were also available. We coordinated...

  • Examining the Tropical Pacific's Response to Global Warming

    Gabriel A. Vecchi; Amy Clement; Brian J. Soden
    Journal Article

    The response of the tropical Pacific to increasing greenhouse gases represents an exciting intersection of theory, modeling, and observations. In this article, we contrast competing theories for the response of the tropical Pacific to global warming, illustrate the utility of models for understanding and reconciling these theories, and...

  • Expansion of the Hadley cell under global warming

    Jian Lu; Gabriel A. Vecchi; Thomas Reichler
    Journal Article

    A consistent weakening and poleward expansion of the Hadley circulation is diagnosed in the climate change simulations of the IPCC AR4 project. Associated with this widening is a poleward expansion of the subtropical dry zone. Simple scaling analysis supports the notion that the poleward extent of the Hadley cell is set by the location where...

  • Extreme North America winter storm season of 2013/14: Roles of radiative forcing and the global warming hiatus

    X. Yang; G. A. Vecchi; T. L. Delworth; K. Paffendorf; R. Gudgel; L. Jia; S. D. Underwood; F. Zeng
    Journal Article

    The extreme 2013/14 winter storm season over much of North America was made more likely by the multiyear anomalous tropical Pacific winds associated with the recent global warming hiatus. © 2015 American Meteorological Society.

  • GFDL's CM2 Global Coupled Climate Models. Part II: The Baseline Ocean Simulation

    Anand Gnanadesikan; Keith W. Dixon; Stephen M. Griffies; V. Balaji; Marcelo Barreiro; Anthony Beesley; William F. Cooke; Thomas L. Delworth; Rudiger Gerdes; Matthew J. Harrison; Isaac M. Held; William J. Hurlin; Hyun-Chul Lee; Zhi Liang; Giang Nong; Ronald C. Pacanowski; Anthony Rosati; Joellen Russell; Bonita L. Samuels; Qian Song; Michael J. Spelman; Ronald J. Stouffer; Colm O. Sweeney; Gabriel Vecchi; Michael Winton; Andrew T. Wittenberg; Fanrong Zeng; Rong Zhang; John P. Dunne
    Journal Article

    The current generation of coupled climate models run at the Geophysical Fluid Dynamics Laboratory (GFDL) as part of the Climate Change Science Program contains ocean components that differ in almost every respect from those contained in previous generations of GFDL climate models. This paper summarizes the new physical features of the models...

  • Global projections of intense tropical cyclone activity for the late twenty-first century from dynamical downscaling of CMIP5/RCP4.5 scenarios

    T. R. Knutson; J. J. Sirutis; M. Zhao; R. E. Tuleya; M. Bender; G. A. Vecchi; G. Villarini; D. Chavas
    Journal Article

    Global projections of intense tropical cyclone activity are derived from the Geophysical Fluid Dynamics Laboratory (GFDL) High Resolution Atmospheric Model (HiRAM; 50-km grid) and the GFDL hurricane model using a two-stage downscaling procedure. First, tropical cyclone genesis is simulated globally using HiRAM. Each storm is then downscaled...

  • Global Warming and the Weakening of the Tropical Circulation

    Gabriel A. Vecchi; Brian J. Soden
    Journal Article

    This study examines the response of the tropical atmospheric and oceanic circulation to increasing greenhouse gases using a coordinated set of twenty-first-century climate model experiments performed for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The strength of the atmospheric overturning circulation...

  • Global warming and the weakening of the tropical circulation

    G. A. Vecchi; B. J. Soden
    Journal Article

    Simple thermodynamic arguments predicts that there is a weakening of atmospheric circulation in response to surface warming due to the rapid increase in water vapor. The response of the tropical atmospheric and oceanic circulation was examined with use of a coordinated set of twenty-first-century climate model experiments. The atmospheric...

  • Global Warming Pattern Formation: Sea Surface Temperature and Rainfall

    Shang-Ping Xie; Clara Deser; Gabriel A. Vecchi; Jian Ma; Haiyan Teng; Andrew T. Wittenberg
    Journal Article

    Spatial variations in sea surface temperature (SST) and rainfall changes over the tropics are investigated based on ensemble simulations for the first half of the twenty-first century under the greenhouse gas (GHG) emission scenario A1B with coupled ocean?atmosphere general circulation models of the Geophysical Fluid Dynamics Laboratory (GFDL)...

  • Greenhouse warming and the 21st century hydroclimate of southwestern North America

    Richard Seager; Gabriel A. Vecchi
    Journal Article

    Climate models robustly predict that the climate of southwestern North America, defined as the area from the western Great Plains to the Pacific Ocean and from the Oregon border to southern Mexico, will dry throughout the current century as a consequence of rising greenhouse gases. This regional drying is part of a general drying of the...

  • Halving warming with idealized solar geoengineering moderates key climate hazards

    P. Irvine; K. Emmanuel; J. He; L. W. Horowitz; G. A. Vecchi; D. Keith
    Journal Article

    Solar geoengineering (SG) has the potential to restore average surface temperatures by increasing planetary albedo 1–4 , but this could reduce precipitation 5–7 . Thus, although SG might reduce globally aggregated risks, it may increase climate risks for some regions 8–10 . Here, using the high-resolution forecast-oriented low ocean resolution...

  • High resolution decadal precipitation predictions over the continental United States for impacts assessment

    K. Salvi; G. Villarini; G. A. Vecchi
    Journal Article

    Unprecedented alterations in precipitation characteristics over the last century and especially in the last two decades have posed serious socio-economic problems to society in terms of hydro-meteorological extremes, in particular flooding and droughts. The origin of these alterations has its roots in changing climatic conditions; however, its...

  • How ocean color can steer Pacific tropical cyclones

    Anand Gnanadesikan; Kerry Emanuel; Gabriel A. Vecchi; Whit G. Anderson; Robert Hallberg
    Journal Article

    Because ocean color alters the absorption of sunlight, it can produce changes in sea surface temperatures with further impacts on atmospheric circulation. These changes can project onto fields previously recognized to alter the distribution of tropical cyclones. If the North Pacific subtropical gyre contained no absorbing and scattering...

  • How skillful are the multiannual forecasts of Atlantic hurricane activity?

    L.-P. Caron; L. Hermanson; A. Dobbin; J. Imbers; L. Lledo; G. A. Vecchi
    Journal Article

    The recent emergence of near-term climate prediction, wherein climate models are initialized with the contemporaneous state of the Earth system and integrated up to 10 years into the future, has prompted the development of three different multiannual forecasting techniques of North Atlantic hurricane frequency. Descriptions of these three...

  • How well do global climate models simulate the variability of Atlantic tropical cyclones associated with ENSO?

    H. Wang; L. Long; A. Kumar; W. Wang; J Schemm; M. Zhao; G.A. Vecchi; T. E. LaRow; Y.-K. Lim; S. D. Schubert; D. A. Shaevitz; S. J. Camargo; N. Henderson; D. Kim; J. A. Jonas; K.J.E. Walsh
    Journal Article

    The variability of Atlantic tropical cyclones (TCs) associated with El Niño-Southern Oscillation (ENSO) in model simulations is assessed and compared with observations. The model experiments are 28-yr simulations forced with the observed sea surface temperature from 1982 to 2009. The simulations were coordinated by the U.S. Climate Variability...

  • Hurricanes and climate: The U.S. Clivar working group on hurricanes

    K.J.E. Walsh; S. J. Camargo; G. A. Vecchi; A. S. Daloz; J. Elsner; K. Emanuel; M. Horn; Y. K. Lim; M. Roberts; C. Patricola; E. Scoccimarro; A. H. Sobel; S. Strazzo; G. Villarini; M. Wehner; M. Zhao; J. P. Kossin; T. La Row; K. Oouchi; S. Schubert; H. Wang; J. Bacmeister; P. Chang; F. Cauvin
    Journal Article

    Although a theory of the climatology of tropical cyclone formation remains elusive, high-resolution climate models can now simulate many aspects of tropical cyclone climate. © 2015 American Meteorological Society.

  • Impact of an observational time window on coupled data assimilation: Simulation with a simple climate model

    Y. Zhao; X Deng; S. Zhang; Z. Liu; C. Liu; G. Vecchi; G. Han; X. Wu
    Journal Article

    Climate signals are the results of interactions of multiple timescale media such as the atmosphere and ocean in the coupled earth system. Coupled data assimilation (CDA) pursues balanced and coherent climate analysis and prediction initialization by incorporating observations from multiple media into a coupled model. In practice, an...

  • The impact of COVID-19 nonpharmaceutical interventions on the future dynamics of endemic infections

    R. E. Baker; S.W. Park; W. Yang; G. A. Vecchi; J. E. Metcalf; B. T. Grenfell
    Journal Article

    Nonpharmaceutical interventions (NPIs) have been employed to reduce the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), yet these measures are already having similar effects on other directly transmitted, endemic diseases. Disruptions to the seasonal transmission patterns of these diseases may have consequences for...

  • Impact of Duration Thresholds on Atlantic Tropical Cyclone Counts

    Christopher W. Landsea; Gabriel A. Vecchi; Lennart Bengtsson; Thomas R. Knutson
    Journal Article

    Records of Atlantic basin tropical cyclones (TCs) since the late nineteenth century indicate a very large upward trend in storm frequency. This increase in documented TCs has been previously interpreted as resulting from anthropogenic climate change. However, improvements in observing and recording practices provide an alternative...

  • The impact of global warming on the tropical Pacific Ocean and El Niño

    Mat Collins; Soon-Il An; Wenju Cai; Alexandre Ganachaud; Eric Guilyardi; Fei-Fei Jin; Markus Jochum; Matthieu Lengaigne; Scott Power; Axel Timmermann; Gabe Vecchi; Andrew Wittenberg
    Journal Article
  • Impact of Ocean Eddy Resolution on the Sensitivity of Precipitation to CO2 Increase

    J. He; B. Kirtman; B. J. Soden; G. A. Vecchi; H. Zhang; M. Winton
    Journal Article

    The past few years have seen a growing investment in the development of global eddy-resolving ocean models, but the impact of incorporating such high ocean resolution on precipitation responses to CO2forcing has yet to be investigated. This study analyzes precipitation changes from a suite of Geophysical Fluid Dynamics Laboratory models...

  • The Impact of Sea Surface Temperature Biases on North American Precipitation in a High-Resolution Climate Model

    Nathaniel C. Johnson; L. Krishnamurthy; A. T. Wittenberg; Baoqiang Xiang; G. Vecchi; S. B. Kapnick; S. Pascale
    Journal Article

    Positive precipitation biases over western North America have remained a pervasive problem in the current generation of coupled global climate models. These biases are substantially reduced, however, in a version of the Geophysical Fluid Dynamics Laboratory Forecast-Oriented Low Ocean Resolution (FLOR) coupled climate model with systematic sea...

  • Impact of strong ENSO on regional tropical cyclone activity in a high-resolution climate model in the North Pacific and North Atlantic Oceans

    L. Krishnamurthy; G. A. Vecchi; R. Msadek; H. Murakami; A. Wittenberg; F. Zeng
    Journal Article

    Tropical cyclone (TC) activity in the North Pacific and North Atlantic Oceans is known to be affected by the El Niño-Southern Oscillation (ENSO). This study uses the GFDL Forecast Oriented Low Ocean Resolution Model (FLOR), which has relatively high resolution in the atmosphere, as a tool to investigate the sensitivity of TC activity to the...

  • Impact of Volcanic Aerosol Hemispheric Symmetry on Sahel Rainfall

    Tess W.P. Jacobson; Wenchang Yang; Gabriel A. Vecchi; Larry W. Horowitz
    Journal Article
    The semi-arid African Sahel region is highly vulnerable to changes in monsoon precipitation, as much of the region’s workforce is employed in the agricultural industry (Hamro-Drotz and Programme, 2011). Thus, studying the response of rainfall and aridity in this region to radiative perturbations is a matter of pressing humanitarian relevance. In...
  • The impacts of changing transport and precipitation on pollutant distributions in a future climate

    Y. Fang; A. M. Fiore; L. W. Horowitz; A. Gnanadesikan; I. Held; G. Chen; G. A. Vecchi; H. Levy
    Journal Article

    [1] Air pollution (ozone and particulate matter in surface air) is strongly linked to synoptic weather and thus is likely sensitive to climate change. In order to isolate the responses of air pollutant transport and wet removal to a warming climate, we examine a simple carbon monoxide–like (CO) tracer (COt) and a soluble version (SAt),...

  • Impacts of the Pacific Meridional Mode on June–August precipitation in the Amazon River Basin

    W. Zhang; G. Villarini; G. A. Vecchi
    Journal Article

    This study examines the impacts of the Pacific Meridional Mode (PMM) on Amazon precipitation during June–August using observations and several experiments with the National Oceanic and Atmospheric Administration/Geophysical Fluid Dynamics Laboratory (NOAA/GFDL) Forecast-oriented Low Ocean Resolution version of CM2.5 (FLOR). We find that the...

  • Impacts of the Pacific Meridional Mode on Landfalling North Atlantic tropical cyclones

    W. Zhang; G. Villarini; G. A. Vecchi; H. Murakami
    Journal Article

    This study examines the impacts of the Pacific Meridional Mode (PMM) on North Atlantic tropical cyclones (TCs) making landfall along the coastal US, Caribbean Islands and Mexico, and provides insights on the underlying physical mechanisms using observations and model simulations. There is a statistically significant time-lagged association...

  • Impacts of the Pacific meridional mode on rainfall over the maritime continent and australia: potential for seasonal predictions

    W. Zhang; G. Villarini; G. A. Vecchi
    Journal Article

    This study assesses whether, the extent to which and why the Pacific Meridional Mode (PMM) modulates rainfall in Australia and the Maritime Continent. We find a statistically significant time-lagged association between March-to-May (MAM) PMM and September-to-November (SON) rainfall in the Maritime Continent and Australia. The association is...

  • Importance of initial conditions in seasonal predictions of Arctic sea ice extent

    R. Msadek; G. A. Vecchi; M. Winton; R. G. Gudgel
    Journal Article

    We present seasonal predictions of Arctic sea ice extent (SIE) over the 1982-2013 period using two suites of retrospective forecasts initialized from a fully coupled ocean-atmosphere-sea ice assimilation system. High skill scores are found in predicting year-to-year fluctuations of Arctic SIE, with significant correlations up to 7 month ahead...

  • Improved ENSO forecasting using Bayesian updating and the North American Multimodel Ensemble (NMME)

    W. Zhang; G. Villarini; L. Slater; G. A. Vecchi; Allen Bradley
    Journal Article

    This study assesses the forecast skill of eight North American Multimodel Ensemble (NMME) models in predicting Niño-3/-3.4 indices and improves their skill using Bayesian updating (BU). The forecast skill that is obtained using the ensemble mean of NMME (NMME-EM) shows a strong dependence on lead (initial) month and target month and is quite...

  • Improved management of small pelagic fisheries through seasonal climate prediction:

    D. Tommasi; C. A. Stock; K. Pegion; G. A. Vecchi; R. D. Methot; M. A. Alexander; D. M. Checkley
    Journal Article

    Populations of small pelagic fish are strongly influenced by climate. The inability of managers to anticipate environment-driven fluctuations in stock productivity or distribution can lead to overfishing and stock collapses, inflexible management regulations inducing shifts in the functional response to human predators, lost opportunities to...

  • Improved seasonal prediction of temperature and precipitation over land in a high-resolution GFDL climate model

    L. Jia; X. Yang; G. A. Vecchi; R. G. Gudgel; T. L. Delworth; A. Rosati; W. F. Stern; A. T. Wittenberg; L. Krishnamurthy; S. Zhang; R. Msadek; S. Kapnick; S. Underwood; F. Zeng; W. G. Anderson; V. Balaji; K. Dixon
    Journal Article
  • Improved simulation of tropical cyclone responses to ENSO in the western north pacific in the high-resolution GFDL HiFLOR coupled climate model

    G. A. Zhang; H. Murakami; T. Delworth; A. T. Wittenberg; A. Rosati; S. Underwood; W. Anderson; L. Harris; R. Gudgel; S. J. Lin; G. Villarini; J. H. Chen
    Journal Article

    This study aims to assess whether, and the extent to which, an increase in atmospheric resolution of the Geophysical Fluid Dynamics Laboratory (GFDL) Forecast-Oriented Low Ocean Resolution version of CM2.5 (FLOR) with 50-km resolution and the High-Resolution FLOR (HiFLOR) with 25-km resolution improves the simulation of the El Niño-Southern...

  • Improved Simulations of Tropical Pacific Annual-Mean Climatein the GFDL FLOR and HiFLOR Coupled GCMs

    A. T. Wittenberg; G. A. Vecchi; T.L. Delworth; A. Rosati; W. G. Anderson; W. F. Cooke; S. Underwood; F. Zeng; S. M. Griffies; S. Ray
    Journal Article

    The National Oceanic and Atmospheric Administration’s Geophysical Fluid DynamicsLaboratory has recently developed two global coupledgeneral circulation models, the Forecast-orientedLow Ocean Resolution (FLOR) model and the High atmospheric resolution Forecast-oriented Low OceanResolution (HiFLOR) model, which are now being utilized for climate...

  • Increased frequency of extreme La Niña events under greenhouse warming

    W. Cai; G. Wang; A. Santoso; M. J. Mcphaden; L. Wu; F. F. Jin; A. Timmermann; M. Collins; G. A. Vecchi; M. Lengaigne; M. H. England; D. Dommenget; K. Takahashi; E. Guilyardi
    Journal Article

    The El Niño/Southern Oscillation is Earth's most prominent source of interannual climate variability, alternating irregularly between El Niño and La Niña, and resulting in global disruption of weather patterns, ecosystems, fisheries and agriculture. The 1998-1999 extreme La Niña event that followed the 1997-1998 extreme El Niño event switched...

  • Increased tropical Atlantic wind shear in model projections of global warming

    G. A. Vecchi; B. J. Soden
    Journal Article

    To help understand possible impacts of anthropogenic greenhouse warming on hurricane activity, we assess model‐projected changes in large‐scale environmental factors tied to variations in hurricane statistics. This study focuses on vertical wind shear (Vs) over the tropical Atlantic during hurricane season, the increase of which has been...

  • Increasing frequency of extreme El Niño events due to greenhouse warming

    W. Cai; S. Borlace; M. Lengaigne; P. Van Rensch; M. Collins; G. Vecchi; A. Timmermann; A. Santoso; M. J. Mcphaden; L. Wu; M. H. England; G. Wang; E. Guilyardi; F. F. Jin
    Journal Article

    El Niño events are a prominent feature of climate variability with global climatic impacts. The 1997/98 episode, often referred to as 'the climate event of the twentieth century', and the 1982/83 extreme El Niño, featured a pronounced eastward extension of the west Pacific warm pool and development of atmospheric convection, and hence a huge...

  • Increasing frequency of extremely severe cyclonic storms over the Arabian Sea

    H. Murakami; G. A. Vecchi; S. Underwood
    Journal Article

    In 2014 and 2015, post-monsoon extremely severe cyclonic storms (ESCS) - defined by the WMO as tropical storms with lifetime maximum winds greater than 46 m s -1 - were first observed over the Arabian Sea (ARB), causing widespread damage. However, it is unknown to what extent this abrupt increase in post-monsoon ESCSs can be linked to...

  • Indian Ocean Dipole Response to Global Warming: Analysis of Ocean–Atmospheric Feedbacks in a Coupled Model

    Xiao-Tong Zheng; Shang-Ping Xie; Gabriel A. Vecchi; Qinyu Liu; Jan Hafner
    Journal Article

    Low-frequency modulation and change under global warming of the Indian Ocean dipole (IOD) mode are investigated with a pair of multicentury integrations of a coupled ocean?atmosphere general circulation model: one under constant climate forcing and one forced by increasing greenhouse gas concentrations. In the unforced simulation, there is...

  • Indian Ocean Variability in the GFDL Coupled Climate Model

    Qian Song; Gabriel A. Vecchi; Anthony J. Rosati
    Journal Article

    The interannual variability of the Indian Ocean, with particular focus on the Indian Ocean dipole/zonal mode (IODZM), is investigated in a 250-yr simulation of the GFDL coupled global general circulation model (CGCM). The CGCM successfully reproduces many fundamental characteristics of the climate system of the Indian Ocean. The character of...

  • The Influence of the Madden–Julian Oscillation on Precipitation in Oregon and Washington

    Nicholas A. Bond; Gabriel A. Vecchi
    Journal Article

    Abstract The Madden-Julian oscillation (MJO) is the primary mode of large-scale intraseasonal variability in the Tropics. Previous work has explored the influences of the MJO on atmospheric circulation anomalies over the North Pacific Ocean and precipitation in California, among other effects. This study focuses on the relationship between the...

  • Influence of the tian shan on arid extratropical Asia

    J. Baldwin; G. Vecchi
    Journal Article

    Arid extratropical Asia (AEA) is bisected at the wetter Tian Shan (a northern offshoot of the Tibetan Plateau) into east and west deserts, each with unique climatological characteristics. The east deserts (~35°- 55°N, ~75°-115°E) have a summer precipitation maximum, and the west deserts (~35°-55°N, ~45°-75°E) have a winter-spring precipitation...

  • Influences of natural variability and anthropogenic forcing on the extreme 2015 accumulated cyclone energy in the Western North Pacific

    W. Zhang; G. A. Vecchi; H. Murakami; G. Villarini; T. L. Delworth; K. Paffendorf; R. Gudgel; L. Jia; F. Zeng; X. Yang
    Journal Article

    The extreme value of the 2015 western North Pacific (WNP) accumulated cyclone energy (ACE) was mainly caused by the sea surface warming in the eastern and central Pacific, with the anthropogenic forcing largely increasing the odds of the occurrence of this event. © 2016 American Meteorological Society.

  • Intense precipitation events associated with landfalling tropical cyclones in response to a warmer climate and increased CO2

    E. Scoccimarro; S. Gualdi; G. Villarini; K. Walsh; A. Navarra; M. Zhao
    Journal Article

    In this work the authors investigate possible changes in the intensity of rainfall events associated with tropical cyclones (TCs) under idealized forcing scenarios, including a uniformly warmer climate, with a special focus on landfalling storms. A new set of experiments designed within the U.S. Climate Variability and Predictability (CLIVAR)...

  • Interannual Indian Rainfall Variability and Indian Ocean Sea Surface Temperature Anomalies

    Gabriel A. Vecchi; D. E. Harrison
    Book Chapter

    This chapter contains sections titled: Introduction Data and Methods Structure of Indian Rainfall Ssta/Rainfall Correlations Discussion

  • Investigating the influence of anthropogenic forcing and natural variability on the 2014 Hawaiian hurricane season

    H. Murakami; G. A. Vecchi; T. L. Delworth; K. Paffendorf; R. Gudgel; L. Jia; F. Zeng
    Journal Article

    New climate simulations suggest that the extremely active 2014 Hawaiian hurricane season was made substantially more likely by anthropogenic forcing, but that natural variability of El Niño was also partially involved. © 2015 American Meteorological Society.

  • January 1999 Indian Ocean Cooling Event

    D. E. Harrison; Gabriel A. Vecchi
    Journal Article

    Unexpectedly strong sub-seasonal SST variability over the tropical Indian Ocean has been observed by the TRMM microwave imager, which provides unprecedented tropical SST information in the presence of clouds. In January-February 1999 SST averaged over an area 20° longitude by 10° latitude cooled by ~1.5°C over 10 days and warmed by ~1.25°C in...

  • Joint projections of US East Coast sea level and storm surge

    C. M. Little; R. M. Horton; R. E. Kopp; M. Oppenheimer; G. A. Vecchi; G. Villarini
    Journal Article
  • Large-scale control on the frequency of tropical cyclones and seeds: a consistent relationship across a hierarchy of global atmospheric models

    T.-L. Hsieh; G. Vecchi; W. Yang; I. M. Held; S. T. Garner
    Journal Article

    A diagnostic framework is developed to explain the response of tropical cyclones (TCs) to climate in high-resolution global atmospheric models having different complexity of boundary conditions. The framework uses vortex dynamics to identify the large-scale control on the evolution of TC precursors—first non-rotating convective...

  • Large-scale environmental controls on the seasonal statistics of rapidly intensifying North Atlantic tropical cyclones

    Ching Ho Justin Ng; Gabriel A. Vecchi
    Journal Article

    This study is concerned with the connections between the large-scale environment and the seasonal occurrence of rapid intensification (RI) of North Atlantic tropical cyclones. Physically-motivated statistical analysis using observations and reanalysis products suggests that for tropical cyclones over the open tropical North Atlantic, the...

  • Lifetime evolution of outer tropical cyclone size and structure as diagnosed from reanalysis and climate model data

    B. A. Schenkel; B. Lin; D. Chavas; G. A. Vecchi; M. Oppenheimer; A. Brammer
    Journal Article

    The present study examines the lifetime evolution of outer tropical cyclone (TC) size and structure in the North Atlantic (NA) and western North Pacific (WNP). The metric for outer TC size is the radius at which the azimuthal-mean 10-m azimuthal wind equals 8 m s-1(r8) derived from the NCEP Climate Forecast System Reanalysis (CFSR) and GFDL...

  • A link between the hiatus in global warming and North American drought

    T. L. Delworth; F. Zeng; A. Rosati; G. A. Vecchi; A. T. Wittenberg
    Journal Article

    Portions of western North America have experienced prolonged drought over the last decade. This drought has occurred at the same time as the global warming hiatus-a decadal period with little increase in global mean surface temperature. Climate models and observational analyses are used to clarify the dual role of recent tropical Pacific...

  • Long term changes in flooding and heavy rainfall associated with North Atlantic tropical cyclones: Roles of the North Atlantic Oscillation and El Niño-Southern Oscillation

    Y. N. Aryal; G. Villarini; W. Zhang; G. A. Vecchi
    Journal Article

    © 2018 Elsevier B.V. The aim of this study is to examine the contribution of North Atlantic tropical cyclones (TCs) to flooding and heavy rainfall across the continental United States. Analyses highlight the spatial variability in these hazards, their temporal changes in terms of frequency and magnitude, and their connection to large-scale...

  • The Madden-Julian Oscillation (MJO) and northern high latitude wintertime surface air temperatures

    Gabriel A. Vecchi; Nicholas A. Bond
    Journal Article

    The Madden-Julian Oscillation (MJO) is the primary mode of large-scale intraseasonal variability in the tropics. Recent work has connected the MJO to atmospheric variability in mid-latitudes. We focus on relationships between the MJO and wintertime surface air temperatures in the Northern Hemisphere high latitudes. The MJO is diagnosed using...

  • Managing living marine resources in a dynamic environment: The role of seasonal to decadal climate forecasts

    D. Tommasi; C. A. Stock; A. J. Hobday; R. Methot; I. C. Kaplan; J. P. Eveson; K. Holsman; T. J. Miller; S. Gaichas; M. Gehlen; A. Pershing; G. A. Vecchi; R. Msadek; T. Delworth; C. M. Eakin; M.A Haltuch; R. Seferian; Spillman; Hartog; Siedlecki; Samhouri
    Journal Article

    Recent developments in global dynamical climate prediction systems have allowed for skillful predictions of climate variables relevant to living marine resources (LMRs) at a scale useful to understanding and managing LMRs. Such predictions present opportunities for improved LMR management and industry operations, as well as new research avenues...

  • Mean climate controls on the simulated response of ENSO to increasing greenhouse gases

    P. N. Dinezio; B. P. Kirtman; A. C. Clement; S.-K. Lee; G. A. Vecchi; A. Wittenberg
    Journal Article

    Climate model experiments are analyzed to elucidate if and how the changes in mean climate in response to doubling of atmospheric CO2 (2xCO2) influence ENSO. The processes involved the development, transition, and decay of simulated ENSO events are quantified through a multimodel heat budget analysis. The simulated changes in ENSO amplitude in...

  • Model Projections of an Imminent Transition to a More Arid Climate in Southwestern North America

    Richard Seager; Mingfang Ting; Isaac Held; Yochanan Kushnir; Jian Lu; Gabriel Vecchi; Huei-Ping Huang; Nili Harnik; Ants Leetmaa; Ngar-Cheung Lau; Cuihua Li; Jennifer Velez; Naomi Naik
    Journal Article

    How anthropogenic climate change will affect hydroclimate in the arid regions of southwestern North America has implications for the allocation of water resources and the course of regional development. Here we show that there is a broad consensus among climate models that this region will dry in the 21st century and that the transition to a...

  • Modeled Impact of Anthropogenic Warming on the Frequency of Intense Atlantic Hurricanes

    Morris A. Bender; Thomas R. Knutson; Robert E. Tuleya; Joseph J. Sirutis; Gabriel A. Vecchi; Stephen T. Garner; Isaac M. Held
    Journal Article

    Several recent models suggest that the frequency of Atlantic tropical cyclones could decrease as the climate warms. However, these models are unable to reproduce storms of category 3 or higher intensity. We explored the influence of future global warming on Atlantic hurricanes with a downscaling strategy by using an operational hurricane-...

  • Modeling the Dependence of Tropical Storm Counts in the North Atlantic Basin on Climate Indices

    Gabriele Villarini; Gabriel A. Vecchi; James A. Smith
    Journal Article

    The authors analyze and model time series of annual counts of tropical storms lasting more than 2 days in the North Atlantic basin and U.S. landfalling tropical storms over the period 1878–2008 in relation to different climate indices. The climate indices considered are the tropical Atlantic sea surface temperature (SST), tropical mean SST,...

  • Modulation of western North Pacific tropical cyclone activity by the Atlantic Meridional Mode

    W. Zhang; G. A. Vecchi; G. Villarini; H. Murakami; A. Rosati; X. Yang; L. Jia; F. Zeng
    Journal Article

    This study examines the year-to-year modulation of the western North Pacific (WNP) tropical cyclones (TC) activity by the Atlantic Meridional Mode (AMM) using both observations and the Geophysical Fluid Dynamics Laboratory Forecast-oriented Low Ocean Resolution Version of CM2.5 (FLOR) global coupled model. 1. The positive (negative) AMM phase...

  • Monsoon Breaks and Subseasonal Sea Surface Temperature Variability in the Bay of Bengal

    Gabriel A. Vecchi; D. E. Harrison
    Journal Article

    The Indian southwest monsoon directly affects the lives of over one billion people, providing almost 90% of the annual precipitation to the Indian subcontinent. An important characteristic of the southwest monsoon is variability on subseasonal timescales, with "active" periods of heavy rain interrupted by drier"break" periods. Both the number...

  • Multi-annual Climate predictions for fisheries: An assessment of skill of sea surface temperature forecasts for large marine ecosystems

    D. Tommasi; C. A. Stock; M. A. Alexander; X. Yang; A. Rosati; G. A. Vecchi
    Journal Article

    Decisions made by fishers and fisheries managers are informed by climate and fisheries observations that now often span more than 50 years. Multi-annual climate forecasts could further inform such decisions if they were skillful in predicting future conditions relative to the 50-year scope of past variability. We demonstrate that an existing...

  • Multi-model ensemble forecasting of North Atlantic tropical cyclone activity

    G. Villarini; B. Luitel; G. A. Vecchi; J. Ghosh
    Journal Article

    North Atlantic tropical cyclones (TCs) and hurricanes are responsible for a large number of fatalities and economic damage. Skillful seasonal predictions of the North Atlantic TC activity can provide basic information critical to our improved preparedness. This study focuses on the development of statistical–dynamical seasonal forecasting...

  • Multiseason lead forecast of the north atlantic power dissipation index (PDI) and accumulated cyclone energy (ACE)

    G. Villarini; G. A. Vecchi
    Journal Article

    By considering the intensity, duration, and frequency of tropical cyclones, the power dissipation index (PDI) and accumulated cyclone energy (ACE) are concise metrics routinely used to assess tropical storm activity. This study focuseson the development of a hybrid statistical-dynamical seasonal forecasting system for the North Atlantic Ocean's...

  • Multiyear predictions of north atlantic hurricane frequency: Promise and limitations

    G. A. Vecchi; R. Msadek; W. Anderson; Y.-S. Chang; T. Delworth; K. Dixon; R. Gudgel; A. Rosati; B. Stern; G. Villarini; A. Wittenberg; X. Yang; F. Zeng; R. Zhang; S. Zhang
    Journal Article

    Retrospective predictions of multiyear North Atlantic Ocean hurricane frequency are explored by applying a hybrid statistical-dynamical forecast system to initialized and noninitialized multiyear forecasts of tropical Atlantic and tropical-mean sea surface temperatures (SSTs) from two global climate model forecast systems. By accounting for...

  • Next season's hurricanes

    G. A. Vecchi; G. Villarini
    Journal Article

    Seasonal predictions of hurricane activity remain challenging, especially at a regional scale.

  • No access the impact of horizontal resolution on north american monsoon gulf of california moisture surges in a suite of coupled global climate models

    S. Pascale; S. Bordoni; S. B. Kapnick; G. A. Vecchi; L. Jia; T. L. Delworth; S. Underwood; W. Anderson
    Journal Article
  • Nonlinear zonal wind response to ENSO in the CMIP5 models: Roles of the zonal and meridional shift of the ITCZ/SPCZ and the simulated climatological precipitation

    K.-Y. Choi; G. A. Vecchi; A. T. Wittenberg
    Journal Article

    The observed equatorial Pacific zonal wind response during El Niño tends to be stronger than during La Niña. Most global coupled climate models in phase 5 of CMIP (CMIP5) exhibit such nonlinearity, although weaker than observed. The wind response nonlinearity can be reproduced by driving a linear shallow water atmospheric model with a model's...

  • Nonlinear zonal wind response to ENSO in the CMIP5 models: Roles of the zonal and meridional shift of the ITCZ/SPCZ and the simulated climatological precipitation

    K.-Y. Choi; G. A. Vecchi; A. T. Wittenberg
    Journal Article

    The observed equatorial Pacific zonal wind response during El Niño tends to be stronger than during La Niña. Most global coupled climate models in phase 5 of CMIP (CMIP5) exhibit such nonlinearity, although weaker than observed. The wind response nonlinearity can be reproduced by driving a linear shallow water atmospheric model with a model's...

  • North Atlantic Hurricane Activity: Past, Present and Future

    R. Msadek; G. A. Vecchi; T. R. Knutson
    Book Chapter

    We review past, present and future North Atlantic hurricane activity based on analysis of observational records and models projections. When adjusted for likely missed tropical cyclones, the observational record does not show any significant increase or decrease of North Atlantic hurricane frequency. Downscaling results for most available CMIP5...

  • The North Atlantic Oscillation as a driver of rapid climate change in the Northern Hemisphere

    T. L. Delworth; F. Zeng; G. A. Vecchi; X. Yang; L. Zhang; R. Zhang
    Journal Article
  • North Atlantic Power Dissipation Index (PDI) and Accumulated Cyclone Energy (ACE): Statistical Modeling and Sensitivity to Sea Surface Temperature Changes

    Gabriele Villarini; Gabriel A. Vecchi
    Journal Article

    This study focuses on the statistical modeling of the power dissipation index (PDI) and accumulated cyclone energy (ACE) for the North Atlantic basin over the period 1949?2008, which are metrics routinely used to assess tropical storm activity, and their sensitivity to sea surface temperature (SST) changes. To describe the variability exhibited...

  • North atlantic tropical cyclones and U.S. flooding

    G. Villarini; R. Goska; J. A. Smith; G. A. Vecchi
    Journal Article

    North Atlantic tropical cyclones (TCs) are responsible for major flooding over large areas of the continental United States. The study focused on flooding over the continental United States associated with North Atlantic TCs during the period 1981-2011. Analyses were based on USGS discharge measurements and provided a characterization of the U....

  • North Atlantic Tropical Storm Frequency Response to Anthropogenic Forcing: Projections and Sources of Uncertainty

    Gabriele Villarini; Gabriel A. Vecchi; Thomas R. Knutson; Ming Zhao; James A. Smith
    Journal Article

    The impact of future anthropogenic forcing on the frequency of tropical storms in the North Atlantic basin has been the subject of intensive investigation. However, whether the number of North Atlantic tropical storms will increase or decrease in a warmer climate is still heavily debated and a consensus has yet to be reached. To shed light on...

  • Observational Evidence for Oceanic Controls on Hurricane Intensity

    Ian D. Lloyd; Gabriel A. Vecchi
    Journal Article

    The influence of oceanic changes on tropical cyclone activity is investigated using observational estimates of sea surface temperature (SST), air-sea fluxes, and ocean subsurface thermal structure during the period 1998-2007. SST conditions are examined before, during, and after the passage of tropical cyclones, through Lagrangian composites...

  • The observing system monitoring center: A tool for the evaluation of the global ocean observing system

    K O'Brien; K. McHugh; G. Vecchi; E. Harrison; S. Hankin; A Manke
    Conference Paper

    The development, evaluation and maintenance of a global observing system named as Observing System Monitoring Center (OSMC) is discussed. OSMC is being constructed in order to assess the effectiveness of the current global ocean observing system as well as to aid in the planning and evaluation of new observing system components. The OSMC will...

  • An Observing System Simulation Experiment for the Indian Ocean

    Gabriel A. Vecchi; Matthew J. Harrison
    Journal Article

    An integrated in situ Indian Ocean observing system (IndOOS) is simulated using a high-resolution ocean general circulation model (OGCM) with daily mean forcing, including an estimate of subdaily oceanic variability derived from observations. The inclusion of subdaily noise is fundamental to the results; in the mixed layer it is parameterized...

  • Ocean-Atmosphere Interactions During Cyclone Nargis

    Michael J. McPhaden; Gregory R. Foltz; Tony Lee; V. S.N. Murty; M. Ravichandran; Gabriel A. Vecchi; Jerome Vialard; Jerry D. Wiggert; Lisan Yu
    Journal Article

    Cyclone Nargis (Figure 1a) made landfall in Myanmar (formerly Burma) on 2 May 2008 with sustained winds of approximately 210 kilometers per hour, equivalent to a category 3?4 hurricane. In addition, Nargis brought approximately 600 millimeters of rain and a storm surge of 3?4 meters to the low-lying and densely populated Irrawaddy River delta....

  • Ocean–Atmosphere Covariability in the Western Arabian Sea

    Gabriel A. Vecchi; Shang-Ping Xie; Albert S. Fischer
    Journal Article

    Abstract The western Arabian Sea exhibits strong spatial variability in sea surface temperature (SST) during the southwest monsoon, with changes in SST that can exceed 5°C over 200 km. Exploration of satellite-based and in situ data shows a strong connection between mesoscale SST features and changes in the atmospheric boundary layer. The...

  • An OSSE Study for Deep Argo Array using the GFDL Ensemble Coupled Data Assimilation System

    Y.-S. Chang; S. Zhang; A. Rosati; G. A. Vecchi; X. Yang
    Journal Article

    2018, Korea Institute of Ocean Science & Technology (KIOST) and the Korean Society of Oceanography (KSO) and Springer Nature B.V. An observing system simulation experiment (OSSE) using an ensemble coupled data assimilation system was designed to investigate the impact of deep ocean Argo profile assimilation in a biased numerical climate...

  • The Pacific meridional mode and the occurrence of tropical Cyclones in the western North Pacific

    W. Zhang; G. A. Vecchi; H. Murakami; G. Villarini; L. Jia
    Journal Article

    This study investigates the association between the Pacific meridional mode (PMM) and tropical cyclone (TC) activity in the western North Pacific (WNP). It is found that the positive PMM phase favors the occurrence of TCs in the WNP while the negative PMM phase inhibits the occurrence of TCs there. Observed relationships are consistent with...

  • The poleward migration of the location of tropical cyclone maximum intensity

    J. P. Kossin; K. A. Emanuel; G. A. Vecchi
    Journal Article

    Temporally inconsistent and potentially unreliable global historical data hinder the detection of trends in tropical cyclone activity. This limits our confidence in evaluating proposed linkages between observed trends in tropical cyclones and in the environment. Here we mitigate this difficulty by focusing on a metric that is comparatively...

  • Potential for western US seasonal snowpack prediction

    S. B. Kapnick; X. Yang; G. A. Vecchi; T. L. Delworth; R. Gudgel; S. Malyshev; P. C.D. Milly; E. Shevliakova; S. Underwood; S. A. Margulis
    Journal Article

    Western US snowpack-snow that accumulates on the ground in the mountains-plays a critical role in regional hydroclimate and water supply, with 80% of snowmelt runoff being used for agriculture. While climate projections provide estimates of snowpack loss by the end of the century and weather forecasts provide predictions of weather conditions...

  • Potential Increase in Hazard From Mediterranean Hurricane Activity With Global Warming

    J. J.Gonzál Alemán; S. Pascale; J. Gutierrez-Fernandez; H. Murakami; M. A. Gaertner; G. A. Vecchi
    Journal Article

    Mediterranean hurricanes (Medicanes) are intense cyclones that acquire tropical characteristics, associated with extreme winds and rainfall, thus posing a serious natural hazard to populated areas along Mediterranean coasts. Understanding how Medicanes will change with global warming remains, however, a challenge, because coarse resolution and/...

  • Precipitation sensitivity to local variations in tropical sea surface temperature

    J. He; N.C. Johnson; G.A. Vecchi; B. Kirtman; A.T. Wittenberg; S. Sturm
    Journal Article

    The driving of tropical precipitation by the variability of the underlying sea surface temperature (SST) plays a critical role in the atmospheric general circulation. To assess the precipitation sensitivity to SST variability, it is necessary to observe and understand the relationship between precipitation and SST. However, the precipitation-...

  • Predictability of the Indian Ocean sea surface temperature anomalies in the GFDL coupled model

    Qian Song; Gabriel A. Vecchi; Anthony J. Rosati
    Journal Article

    We explore the predictability of the sea surface temperature anomalies associated with the Indian Ocean Dipole/Zonal Mode (IODZM) at a three-season lead, within the Geophysical Fluid Dynamics Laboratory (GFDL) coupled general circulation model (CGCM). In both control simulations and retrospective forecasts of the 1990's in the CGCM, we find...

  • Predicting a decadal shift in North Atlantic climate variability using the GFDL forecast system

    R. Msadek; T. L. Delworth; A. Rosati; W. Anderson; G. Vecchi; Y.-S. Chang; K. Dixon; R. G. Gudgel; W. Stern; A. Wittenberg; X. Yang; F. Zeng; R. Zhang; S. Zhang
    Journal Article

    Decadal prediction experiments were conducted as part of phase 5 of the Coupled Model Intercomparison Project (CMIP5) using the GFDL ClimateModel, version 2.1 (CM2.1) forecast system. The abrupt warming of the North Atlantic Subpolar Gyre (SPG) that was observed in the mid-1990s is considered as a case study to evaluate forecast capabilities...

  • The present-day simulation and twenty-first-century projection of the climatology of extratropical transition in the North Atlantic

    M. Liu; G. A. Vecchi; J. A. Smith; H. Murakami
    Journal Article

    This study explores the simulations and twenty-first-century projections of extratropical transition (ET) of tropical cyclones (TCs) in the North Atlantic, with a newly developed global climate model: the Forecast-Oriented Low Ocean Resolution (FLOR) version of the Geophysical Fluid Dynamics Laboratory (GFDL) Coupled Model version 2.5 (CM2.5)....

  • Process-oriented diagnosis of tropical cyclones in high-resolution GCMs

    D. Kim; Y. Moon; S. J. Camargo; A. A. Wing; A. H. Sobel; H. Murakami; G. A. Vecchi; M. Zhao; E. Page
    Journal Article

    This study proposes a set of process-oriented diagnostics with the aim of understanding how model physics and numerics control the representation of tropical cyclones (TCs), especially their intensity distribution, in GCMs. Three simulations are made using two 50-km GCMs developed at NOAA’s Geophysical Fluid Dynamics Laboratory. The two models...

  • Projected response of tropical cyclone intensity and intensification in a global climate model

    K. Bhatia; G. Vecchi; H. Murakami; S. Underwood; J. P. Kossin
    Journal Article

    As one of the first global coupled climate models to simulate and predict category 4 and 5 (Saffir-Simpson scale) tropical cyclones (TCs) and their interannual variations, the High-Resolution Forecast-Oriented Low Ocean Resolution (HiFLOR) model at the Geophysical Fluid Dynamics Laboratory (GFDL) represents a novel source of insight on how the...

  • Projected twenty-first-century changes in the length of the tropical cyclone season

    J. G. Dwyer; S. J. Camargo; A. H. Sobel; M. Biasutti; K. A. Emanuel; G. A. Vecchi; M. Zhao; M. K. Tippett
    Journal Article

    This study investigates projected changes in the length of the tropical cyclone season due to greenhouse gas increases. Two sets of simulations are analyzed, both of which capture the relevant features of the observed annual cycle of tropical cyclones in the recent historical record. Both sets use output from the general circulation models (...

  • Projection of Landfalling–Tropical Cyclone Rainfall in the Eastern United States under Anthropogenic Warming

    M. Liu; G. A. Vecchi; J. A. Smith; H. Murakami
    Journal Article

    Landfalling-tropical cyclone (TC) rainfall is an important element of inland flood hazards in the eastern United States. The projection of landfalling-TC rainfall under anthropogenic warming provides insight into future flood risks. This study examines the frequency of landfalling TCs and associated rainfall using the GFDL Forecast-Oriented Low...

  • Rainfall from tropical cyclones: high-resolution simulations and seasonal forecasts

    W. Zhang; G. Villarini; G. A. Vecchi; H. Murakami
    Journal Article

    This study examines the performance of the Geophysical Fluid Dynamics Laboratory Forecast-Oriented Low Ocean Resolution version of CM2.5 (FLOR; ~ 50-km mesh) and high-resolution FLOR (HiFLOR; ~ 25-km mesh) in reproducing the climatology and interannual variability in rainfall associated with tropical cyclones (TCs) in both sea surface...

  • Rapid attribution of the August 2016 flood-inducing extreme precipitation in south Louisiana to climate change

    K. Van Der Wiel; S. B. Kapnick; Jan Van Oldenborgh; K. Whan; S. Philip; G. A. Vecchi; R. K. Singh; J. Arrighi; H. Cullen
    Journal Article

    A stationary low pressure system and elevated levels of precipitable water provided a nearly continuous source of precipitation over Louisiana, United States (US), starting around 10 August 2016. Precipitation was heaviest in the region broadly encompassing the city of Baton Rouge, with a 3-day maximum found at a station in Livingston, LA (east...

  • Reassessing the role of stochastic forcing in the 1997–1998 El Niño

    G. A. Vecchi; A. T. Wittenberg; A. Rosati
    Journal Article

    We explore the extent to which stochastic atmospheric variability was fundamental to development of extreme sea surface temperature anomalies (SSTAs) during the 1997-8 El Niño. The observed western equatorial Pacific westerly zonal stress anomalies (τax), which appeared between Nov. 1996 and May 1997 as a series of episodic bursts, were largely...

  • Recent increases in tropical cyclone intensification rates

    K. T. Bhatia; G. A. Vecchi; T. R. Knutson; H. Murakami; J. P. Kossin; K W. Dixon; C. E. Whitlock
    Journal Article

    Tropical cyclones that rapidly intensify are typically associated with the highest forecast errors and cause a disproportionate amount of human and financial losses. Therefore, it is crucial to understand if, and why, there are observed upward trends in tropical cyclone intensification rates. Here, we utilize two observational datasets to...

  • Is the recorded increase in short-duration North Atlantic tropical storms spurious?

    Gabriele Villarini; Gabriel A. Vecchi; Thomas R. Knutson; James A. Smith
    Journal Article

    The number of North Atlantic tropical storms lasting 2 days or less exhibits a large increase starting from the middle of the 20th century, driving the increase in recorded number of tropical storms over the past century. Here we present a set of quantitative analyses to assess whether this behavior is more likely associated with climate...

  • Regional Arctic sea–ice prediction: potential versus operational seasonal forecast skil

    M. Bushuk; R. Msadek; M. Winton; G. A. Vecchi; X. Yang; A. Rosati; R. Gudgel
    Journal Article

    Seasonal predictions of Arctic sea ice on regional spatial scales are a pressing need for a broad group of stakeholders, however, most assessments of predictability and forecast skill to date have focused on pan-Arctic sea–ice extent (SIE). In this work, we present the first direct comparison of perfect model (PM) and operational (OP) seasonal...

  • Reply to comments on "Multiyear predictions of North Atlantic hurricane frequency: Promise and limitations"

    G. A. Vecchi; R. Msadek; W. Anderson; Y.-S. Chang; T. Delworth; K. Dixon; R. Gudgel; A. Rosati; B. Stern; G. Villarini; A. Wittenberg; X. Yang; F. Zeng; R. Zhang; S. Zhang
    Journal Article
  • The resolution dependence of contiguous U.S. precipitation extremes in response to CO2 forcing

    K. Van Der Wiel; S. B. Kapnick; G. A. Vecchi; W. F. Cooke; T. L. Delworth; L. Jia; H. Murakami; S. Underwood; F. Zeng
    Journal Article

    Precipitation extremes have a widespread impact on societies and ecosystems; it is therefore important to understand current and future patterns of extreme precipitation. Here, a set of new global coupled climate models with varying atmospheric resolution has been used to investigate the ability of these models to reproduce observed patterns of...

  • Response of extreme rainfall forlandfalling tropical cyclones undergoing extratropical transition to projected climate change: Hurricane Irene (2011)

    M. Liu; L. Yang; J. A. Smith; G. A. Vecchi
    Journal Article

    Extreme rainfall and flooding associated with landfalling tropical cyclones (TCs) have large societal impacts, both in fatalities and economic losses. This study examines the response of TC rainfall to climate change projected under future anthropogenic greenhouse emissions,focusing on Hurricane Irene,which produced severe flooding across the...

  • Response of the equatorial pacific seasonal cycle to orbital forcing

    M. P. Erb; A. J. Broccoli; N. T. Graham; A. C. Clement; A. T. Wittenberg; G. A. Vecchi
    Journal Article

    The response of the equatorial Pacific Ocean's seasonal cycle to orbital forcing is explored using idealized simulations with a coupled atmosphere-ocean GCM in which eccentricity, obliquity, and the longitude of perihelion are altered while other boundary conditions are maintained at preindustrial levels. The importance of ocean dynamics in the...

  • The response of the tropical Atlantic and West African climate to Saharan dust in a fully coupled GCM

    J. D.O. Strong; G. A. Vecchi; P. Ginoux
    Journal Article

    This study examines the climate response in West Africa and the tropical Atlantic to an idealized aerosol radiative forcing from Saharan mineral dust, comparable to the observed changes between the 1960s and 1990s, using simulations with the fully coupled GFDL Climate Model, version 2.1 (CM2.1), for two optical property regimes: more absorbing...

  • The response of the Walker circulation to Last Glacial Maximum forcing: Implications for detection in proxies

    P. N. Dinezio; A. Clement; G. A. Vecchi; B. Soden; A. J. Broccoli; B. L. Otto-Bliesner; P. Braconnot
    Journal Article

    The response of the Walker circulation to Last Glacial Maximum (LGM) forcing is analyzed using an ensemble of six coordinated coupled climate model experiments. The tropical atmospheric overturning circulation strengthens in all models in a manner that is dictated by the response of the hydrological cycle to tropical cooling. This response...

  • Retrospective Forecasts of the Hurricane Season Using a Global Atmospheric Model Assuming Persistence of SST Anomalies

    Ming Zhao; Isaac M. Held; Gabriel A. Vecchi
    Journal Article

    Retrospective predictions of seasonal hurricane activity in the Atlantic and east Pacific are generated using an atmospheric model with 50-km horizontal resolution by simply persisting sea surface temperature (SST) anomalies from June through the hurricane season. Using an ensemble of 5 realizations for each year between 1982 and 2008, the...

  • The Risks of Contracting the Acquisition and Processing of the Nation’s Weather and Climate Data to the Private Sector

    Y. L. Serr; J. S. Haase; D. K. Adams; Q. Fu; T. P. Ackerman; M.J. Alexander; A. Arellano; L. Back; K. Emmanuel; Z. Kuang; B. Mapes; D. Neelin; D. Raymond; A. H. Sobel; P. W. Staten; A. Subramanian; D.W.J. Thompson; G. A. Vecchi; R. Wood; P. Zuidema
    Journal Article
  • The Risks of Contracting the Acquisition and Processing of the Nation’s Weather and Climate Data to the Private Sector

  • The Role of the Indonesian Throughflow in the Indo–Pacific Climate Variability in the GFDL Coupled Climate Model

    Qian Song; Gabriel A. Vecchi; Anthony J. Rosati
    Journal Article

    The impacts of the Indonesian Throughflow (ITF) on the tropical Indo?Pacific climate, particularly on the character of interannual variability, are explored using a coupled general circulation model (CGCM). A pair of CGCM experiments?a control experiment with an open ITF and a perturbation experiment in which the ITF is artificially closed?is...

  • The roles of radiative forcing, sea surface temperatures, and atmospheric and land initial conditions in U.S. summer warming episodes

    L. Jia; G. A. Vecchi; X. Yang; R. G. Gudgel; T.L. Delworth; W.F. Stern; K. Paffendorf; S. D. Underwood; F. Zeng
    Journal Article
  • Sea Surface Salinity Response to Tropical Cyclones Based on Satellite Observations

    Jingru Sun; Gabriel A. Vecchi; Brian Soden
    Journal Article

    Multi-year records of satellite remote sensing of sea surface salinity (SSS) provide an opportunity to investigate the climatological characteristics of the SSS response to tropical cyclones (TCs). In this study, the influence of TC winds, rainfall and preexisting ocean stratification on SSS evolution is examined with multiple satellite-based...

  • Sea Surface Temperature of the Bay of Bengal Derived from the TRMM Microwave Imager

    G. S. Bhat; G. A. Vecchi; S. Gadgil
    Journal Article

    The Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) with the capability of measuring sea surface temperature (SST) in the presence of clouds, has been providing an unprecedented view of tropical basin-scale SST variability. In this paper, an assessment of the accuracy of the SST derived from TMI over the Bay of Bengal using in...

  • On the seasonal forecasting of regional tropical cyclone activity

    G. A. Vecchi; T. Delworth; R. Gudgel; S. Kapnick; A. Rosati; A. T. Wittenberg; F. Zeng; W. Anderson; V. Balaji; K. Dixon; L. Jia; H.-S. Kim; L. Krishnamurthy; R. Msadek; W. F. Stern; S. D. Underwood; G. Villarini; X. Yang; S. Zhang
    Journal Article

    Tropical cyclones (TCs) are a hazard to life and property and a prominent element of the global climate system; therefore, understanding and predicting TC location, intensity, and frequency is of both societal and scientific significance. Methodologies exist to predict basinwide, seasonally aggregated TC activity months, seasons, and even years...

  • Seasonal forecasts of major hurricanes and landfalling tropical cyclones using a high-resolution GFDL coupled climate model

    H. Murakami; G. A. Vecchi; G. Villarini; T. L. Delworth; R. Gudgel; S. Underwood; X. Yang; W. Zhang; S.-J. Lin
    Journal Article

    Skillful seasonal forecasting of tropical cyclone (TC; wind speed ≥17.5 m s-1) activity is challenging, even more so when the focus is on major hurricanes (wind speed ≥49.4 m s-1), the most intense hurricanes (category 4 and 5; wind speed ≥58.1 m s-1), and landfalling TCs. This study shows that a 25-km-resolution global climate model [High-...

  • Seasonal Forecasts of Major Hurricanes and Landfalling Tropical Cyclones using a High-Resolution GFDL Coupled Climate Model

    Hiroyuki Murakami; Gabriel A. Vecchi; Gabriele Villarini; Thomas L. Delworth; Richard Gudgel; Seth Underwood; Xiaosong Yang; Wei Zhang; Shian-Jiann Lin
    Journal Article

    AbstractSkillful seasonal forecasting of tropical cyclone (TC; wind speed ≥17.5 m s?1) activity is challenging, even more so when the focus is on major hurricanes (wind speed ≥49.4 m s?1), the most intense hurricanes (category 4 and 5; wind speed ≥58.1 m s?1), and landfalling TCs. This study shows that a 25-km-resolution global climate model [...

  • Seasonal predictability of extratropical storm tracks in GFDL's high-resolution climate prediction model

    X. Yang; G. A. Vecchi; R. G. Gudgel; T. L. Delworth; S. Zhang; A. Rosati; L. Jia; W. F. Stern; A. T. Wittenberg; S. Kapnick; R. Msadek; S. D. Underwood; F. Zeng; W. G. Anderson; V. Balaji
    Journal Article

    The seasonal predictability of extratropical storm tracks in the Geophysical Fluid Dynamics Laboratory's (GFDL)'s high-resolution climate model has been investigated using an average predictability time analysis. The leading predictable components of extratropical storm tracks are the ENSO-related spatial patterns for both boreal winter and...

  • On the seasonal prediction of the western United States El Niño precipitation pattern during the 2015/16 winter

    X. Yang; L. Jia; S. B. Kapnick; T. L. Delworth; G. A. Vecchi; R. Gudgel; S. Underwood; F. Zeng
    Journal Article

    A “typical” El Niño leads to wet (dry) wintertime anomalies over the southern (northern) half of the Western United States
    (WUS). However, during the strong El Niño of 2015/16, the WUS winter precipitation pattern was roughly opposite to
    this canonical (average of the record) anomaly pattern. To understand why this happened, and...

  • Seasonal prediction skill of northern extratropical surface temperature driven by the stratosphere

    L. Jia; X. Yang; G. A. Vecchi; R. Gudgel; T. Delworth; S. Fueglistaler; P. Lin; A. A. Scaife; S. Underwood; S.-J. Lin
    Journal Article

    This study explores the role of the stratosphere as a source of seasonal predictability of surface climate over Northern Hemisphere extratropics both in the observations and climate model predictions. A suite of numerical experiments, including climate simulations and retrospective forecasts, are set up to isolate the role of the stratosphere...

  • Seasonal sea surface temperature anomaly prediction for coastal ecosystems

    C. A. Stock; K. Pegion; G. A. Vecchi; M. A. Alexander; D. Tommasi; N. A. Bond; P. S. Fratantoni; R. G. Gudgel; T. Kristiansen; T. D. O'Brien; Y. Xue; X. Yang
    Journal Article

    Sea surface temperature (SST) anomalies are often both leading indicators and important drivers of marine resource fluctuations. Assessment of the skill of SST anomaly forecasts within coastal ecosystems accounting for the majority of global fish yields, however, has been minimal. This reflects coarse global forecast system resolution and past...

  • Seasonality and predictability of the Indian Ocean dipole mode: ENSO forcing and internal variability

    Y. Yang; S.-P. Xie; L. Wu; Y. Kosaka; N. C. Lau; G. A. Vecchi
    Journal Article

    This study evaluates the relative contributions to the Indian Ocean dipole (IOD) mode of interannual variability from the El Niño-Southern Oscillation (ENSO) forcing and ocean-atmosphere feedbacks internal to the Indian Ocean. The ENSO forcing and internal variability is extracted by conducting a 10-member coupled simulation for 1950-2012 where...

  • The seasonality of the great plains low-level Jet and ENSO relationship

    L. Krisnamurthy; G. A. Vecchi; R. Msadek; A. T. Wittenberg; T. L. Delworth; F. Zeng
    Journal Article

    This study investigates the seasonality of the relationship between the Great Plains low-level jet (GPLLJ) and the Pacific Ocean from spring to summer, using observational analysis and coupled model experiments. The observed GPLLJ and El Niño-Southern Oscillation (ENSO) relation undergoes seasonal changes with a stronger GPLLJ associated with...

  • Sensitivity of tropical cyclone rainfall to idealized global-scale forcings

    G. Villarini; D A. Lavers; E. Scoccimarro; M. Zhao; M. F. Wehner; G. A. Vecchi; T.R. Knutson; K. A. Reed
    Journal Article

    Heavy rainfall and flooding associated with tropical cyclones (TCs) are responsible for a large number of fatalities and economic damage worldwide. Despite their large socioeconomic impacts, research into heavy rainfall and flooding associated with TCs has received limited attention to date and still represents a major challenge. The capability...

  • Setting the timing of El Niño termination

    G. A. Vecchi; A. Rosati; D. E. Harrison
    Journal Article
  • Shifting patterns of mild weather in response to projected radiative forcing

    K. Van Der Wiel; S. B. Kapnick; G. A. Vecchi
    Journal Article
  • Simulated Climate and Climate Change in the GFDL CM2.5 High-Resolution Coupled Climate Model

    Thomas L. Delworth; Anthony Rosati; Whit Anderson; Alistair J. Adcroft; V. Balaji; Rusty Benson; Keith Dixon; Stephen M. Griffies; Hyun-Chul Lee; Ronald C. Pacanowski; Gabriel A. Vecchi; Andrew T. Wittenberg; Fanrong Zeng; Rong Zhang
    Journal Article

    The authors present results for simulated climate and climate change from a newly developed high-resolution global climate model [Geophysical Fluid Dynamics Laboratory Climate Model version 2.5 (GFDL CM2.5)]. The GFDL CM2.5 has an atmospheric resolution of approximately 50 km in the horizontal, with 32 vertical levels. The horizontal resolution...

  • Simulated connections between ENSO and tropical cyclones near guam in a high-resolution GFDL coupled climate model: Implications for seasonal forecasting

    W. Zhang; G. A. Vecchi; G. Villarini; H. Murakami; T. Delworth; L. Jia; R. Gudgel; F. Zeng
    Journal Article

    This study aims to assess the connections between El Niño-Southern Oscillation (ENSO) and tropical cyclones near Guam (GuamTCs) using the state-of-the-art Geophysical Fluid Dynamics Laboratory (GFDL) Forecast-Oriented Low Ocean Resolution version of CM2.5 (FLOR). In observations, more (fewer) GuamTCs occur in El Niño (La Niña) years, and the...

  • Simulated reduction in Atlantic hurricane frequency under twenty-first-century warming conditions

    Thomas R. Knutson; Joseph J. Sirutis; Stephen T. Garner; Gabriel A. Vecchi; Isaac M. Held
    Journal Article

    Increasing sea surface temperatures in the tropical Atlantic Ocean and measures of Atlantic hurricane activity have been reported to be strongly correlated since at least 1950 (refs ...

  • Simulation and prediction of category 4 and 5 hurricanes in the high-resolution GFDL HiFLOR coupled climate model

    H. Murakami; G. A. Vecchi; S. Underwood; T. L. Delworth; A. T. Wittenberg; W. G. Anderson; J. H. Chen; R. G. Gudgel; L. M. Harris; S. J. Lin; F. Zeng
    Journal Article

    A new high-resolution Geophysical Fluid Dynamics Laboratory (GFDL) coupled model [the High-Resolution Forecast-Oriented Low Ocean Resolution (FLOR) model (HiFLOR)] has been developed and used to investigate potential skill in simulation and prediction of tropical cyclone (TC) activity. HiFLOR comprises high-resolution (~25-km mesh) atmosphere...

  • Simulations of Global Hurricane Climatology, Interannual Variability, and Response to Global Warming Using a 50-km Resolution GCM

    Ming Zhao; Isaac M. Held; Shian-Jiann Lin; Gabriel A. Vecchi
    Journal Article

    A global atmospheric model with roughly 50-km horizontal grid spacing is used to simulate the interannual variability of tropical cyclones using observed sea surface temperatures (SSTs) as the lower boundary condition. The model's convective parameterization is based on a closure for shallow convection, with much of the deep convection allowed...

  • Skillful regional prediction of Arctic sea ice on seasonal timescales

    M Bushuk; R. Msadek; M. Winton; G. A. Vecchi; R. . Gudgel; A. Rosati; X. Yang
    Journal Article

    Recent Arctic sea ice seasonal prediction efforts and forecast skill assessments have primarily focused on pan-Arctic sea ice extent (SIE). In this work, we move toward stakeholder-relevant spatial scales, investigating the regional forecast skill of Arctic sea ice in a Geophysical Fluid Dynamics Laboratory (GFDL) seasonal prediction system....

  • Statistical-dynamical seasonal forecast of north atlantic and U.S. landfalling tropical cyclones using the high-resolution GFDL FLOR coupled model

    H. Murakami; G. Villarini; G. A. Vecchi; W. Zhang; R. Gudgel
    Journal Article

    Retrospective seasonal forecasts of North Atlantic tropical cyclone (TC) activity over the period 1980-2014 are conducted using a GFDL high-resolution coupled climate model [Forecast-Oriented Low Ocean Resolution (FLOR)]. The focus is on basin-total TC and U.S. landfall frequency. The correlations between observed and model predicted basin-...

  • Statistical–Dynamical Predictions of Seasonal North Atlantic Hurricane Activity

    Gabriel A. Vecchi; Ming Zhao; Hui Wang; Gabriele Villarini; Anthony Rosati; Arun Kumar; Isaac M. Held; Richard Gudgel
    Journal Article

    Skillfully predicting North Atlantic hurricane activity months in advance is of potential societal significance and a useful test of our understanding of the factors controlling hurricane activity. In this paper, a statistical?dynamical hurricane forecasting system, based on a statistical hurricane model, with explicit uncertainty estimates,...

  • Stronger influences of increased CO2 on subdaily precipitation extremes than at the daily scale

    W. Zhang; G. Villarini; E. Scoccimarro; G. A. Vecchi
    Journal Article

    Based on idealized experiments (preindustrial control experiment (PI) and 1% yr−1 increase (1%CO2) in atmospheric CO2) from 10 general circulation models produced under the Coupled Model Intercomparison Project Phase 5 and using the fraction of attributable risk, we examine the CO2 effects on extreme precipitation at the subdaily and daily...

  • Submonthly Indian Ocean Cooling Events and Their Interaction with Large-Scale Conditions

    Ian D. Lloyd; Gabriel A. Vecchi
    Journal Article

    The Indian Ocean exhibits strong variability on a number of time scales, including prominent intraseasonal variations in both the atmosphere and ocean. Of particular interest is the south tropical Indian Ocean thermocline ridge, a region located between 12° and 5°S, which exhibits prominent variability in sea surface temperature (SST) due to...

  • Subseasonal atmospheric variability and El Niño waveguide warming: Observed effects of the Madden-Julian oscillation and westerly wind events

    A. M. Chiodi; D. E. Harrison; G. A. Vecchi
    Journal Article

    Westerly wind events (WWEs) have previously been shown to initiate equatorial Pacific waveguide warming. The relationship between WWEs and Madden-Julian oscillation (MJO) activity, as well as the role of MJO events in initiating waveguide warming, is reconsidered here over the 1986-2010 period. WWEs are identified in observations of near-...

  • Summer enhancement of Arctic sea ice volume anomalies in the September-ice zone

    M. Bushuk; R. Msadek; M. Winton; G. A. Vecchi; R. Gudgel; A. Rosati; X. Yang
    Journal Article

    Because of its persistence on seasonal time scales, Arctic sea ice thickness (SIT) is a potential source of predictability for summer sea ice extent (SIE). New satellite observations of SIT represent an opportunity to harness this potential predictability via improved thickness initialization in seasonal forecast systems. In this work, the...

  • Susceptible supply limits the role of climate in the early SARS-CoV-2 pandemic.

    R.E. Baker; W. Yang; G. A. Vecchi; C. J.E. Metcalf; B. T. Grenfell
    Journal Article

    Preliminary evidence suggests that climate may modulate the transmission of SARS-CoV-2. Yet it remains unclear whether seasonal and geographic variations in climate can substantially alter the pandemic trajectory, given high susceptibility is a core driver. Here, we use a climate-dependent epidemic model to simulate the SARS-CoV-2 pandemic...

  • Temporally Compound Heat Wave Events and Global Warming: An Emerging Hazard

    J.W. Baldwin; J.B. Dessy; G. A. Vecchi; M. Opppenheimer
    Journal Article

    The temporal structure of heat waves having substantial human impact varies widely, with many featuring a compound structure of hot days interspersed with cooler breaks. In contrast, many heat wave definitions employed by meteorologists include a continuous threshold-exceedance duration criterion. This study examines the hazard of these diverse...

  • On the termination of El Niño

    D. E. Harrison; Gabriel A. Vecchi
    Journal Article

    A feature of the end-phase of recent El Niño periods is thermocline shallowing to normal depths, in the central and eastern equatorial Pacific, before sea surface temperature (SST) returns to normal. Also characteristic of El Niño periods is a late-in-the-year shift of the El Niño equatorial westerly wind anomalies, from symmetric about the...

  • The Termination of the 1997–98 El Niño. Part I: Mechanisms of Oceanic Change

    Gabriel A. Vecchi; D. E. Harrison
    Journal Article

    The 1997-98 El Niño was both unusually strong and terminated unusually. Warm eastern equatorial Pacific (EEqP) sea surface temperature anomalies (SSTAs) exceeded 4°C at the event peak and lasted well into boreal spring of 1998, even though subsurface temperatures began cooling in December 1997. The oceanic processes that controlled this unusual...

  • The Termination of the 1997–98 El Niño. Part II: Mechanisms of Atmospheric Change

    Gabriel A. Vecchi
    Journal Article

    The mechanisms that drove zonal wind stress (τx) changes in the near-equatorial Pacific at the end of the extreme 1997-98 El Niño event are explored using a global atmospheric general circulation model. The analysis focuses on three features of the τx evolution between October 1997 and May 1998 that were fundamental in driving the oceanic...

  • On the termination of the 2002–03 El Niño event

    Gabriel A. Vecchi; D. E. Harrison
    Journal Article

    Every new El Niño presents an opportunity to revisit our understanding of El Niño characteristics and processes. We examine the extent to which the termination of the 2002-03 El Niño followed the scenario of Harrison and Vecchi [1999], in which (1) there is a late-year southward shift of near-equatorial westerly wind anomalies, and (2)...

  • Thermodynamic and Dynamic Mechanisms for Large-Scale Changes in the Hydrological Cycle in Response to Global Warming

    Richard Seager; Naomi Naik; Gabriel A. Vecchi
    Journal Article

    Abstract The mechanisms of changes in the large-scale hydrological cycle projected by 15 models participating in the Coupled Model Intercomparison Project phase 3 and used for the Intergovernmental Panel on Climate Change's Fourth Assessment Report are analyzed by computing differences between 2046 and 2065 and 1961 and 2000. The contributions...

  • Towards Dynamical Seasonal Forecast of Extratropical Transition in the North Atlantic

    M. Liu; G. A. Vecchi; J. A. Smith; H. Murakami; R. Gudgel; X. Yang
    Journal Article

    Abstract Extratropical transition can extend the threat of tropical cyclones into the midlatitudes and modify it through expansion of rainfall and wind fields. Despite the scientific and socioeconomic interest, the seasonal forecast of extratropical transition has received little attention. The GFDL High-Resolution Forecast-Oriented Low Ocean...

  • Towards predictive understanding of regional climate change

    S. P. Xie; C. Deser; G. A. Vecchi; M. Collins; T. L. Delworth; A. Hall; E. Hawkins; N. C. Johnson; C. Cassou; A. Giannini; M. Watanabe
    Journal Article

    Regional information on climate change is urgently needed but often deemed unreliable. To achieve credible regional climate projections, it is essential to understand underlying physical processes, reduce model biases and evaluate their impact on projections, and adequately account for internal variability. In the tropics, where atmospheric...

  • Transient climate sensitivity depends on base climate ocean circulation

    J. He; M. Winton; G. Vecchi; L. Jia; M. Rugenstein
    Journal Article
  • Tropical cyclone rainfall changes in a warmer climate ( Book Chapter)

    E. Scoccimarro; G. Villarini; S. Gualdi; A. Navarra; G. A. Vecchi; K. Walsh; M. Zhao
    Book Chapter

    Heavy precipitation and flooding associated with tropical cyclones (TCs) are responsible for a large number of fatalities and economic damage worldwide. Due to the societal and economic relevance of this hazard, studies have focused on the potential changes in heavy rainfall associated with TCs in a warmer climate. Despite the overall agreement...

  • Tropical cyclone sensitivities to CO2 doubling: roles of atmospheric resolution, synoptic variability and background climate changes

    Gabriel A. Vecchi; Thomas L. Delworth; Hiroyuki Murakami; Seth D. Underwood; Andrew T. Wittenberg; Fanrong Zeng; Wei Zhang; Jane W. Baldwin; Kieran T. Bhatia; William Cooke; Jie He; Sarah B. Kapnick; Thomas R. Knutson; Gabriele Villarini; Karin van der Wiel; Whit Anderson; V. Balaji; Jan–Huey Chen; Keith W. Dixon; Rich Gudgel; Lucas M. Harris; Liwei Jia; Nathaniel C. Johnson; Shian-Jiann Lin; Maofeng Liu; Ching Ho Justin Ng; Anthony Rosati; James A. Smith; Xiaosong Yang
    Journal Article

    Responses of tropical cyclones (TCs) to CO2 doubling are explored using coupled global climate models (GCMs) with increasingly refined atmospheric/land horizontal grids (~ 200 km, ~ 50 km and ~ 25 km). The three models exhibit similar changes in background climate fields thought to regulate TC activity, such as relative sea surface temperature...

  • Tropical cyclone simulation and response to CO2 doubling in the GFDL CM2.5 high-resolution coupled climate model

    H.-S. Kim; G. A. Vecchi; T. R. Knutson; W. G. Anderson; T. L. Delworth; A. Rosati; F. Zeng; M. Zhao
    Journal Article

    Global tropical cyclone (TC) activity is simulated by the Geophysical Fluid Dynamics Laboratory (GFDL) Climate Model, version 2.5 (CM2.5), which is a fully coupled global climate model with a horizontal resolution of about 50km for the atmosphere and 25km for the ocean. The present climate simulation shows a fairly realistic global TC frequency...

  • Tropical Meteorology & Climate: Hadley Circulation

    J. Lu; G. A. Vecchi
    Book Chapter

    The Hadley circulation, a prominent circulation feature characterized by rising air near the Equator and sinking air in the subtropics, defines the position of dry subtropical areas and is a fundamental regulator of the earth's energy and momentum budgets. The character of the Hadley circulation, and its related precipitation regimes, exhibits...

  • Tropical Pacific Sea Surface Temperature Anomalies, El Niño, and Equatorial Westerly Wind Events

    Gabriel A. Vecchi; D. E. Harrison
    Journal Article

    Abstract The authors examine global statistical relationships between westerly wind events (WWEs) and sea surface temperature anomaly (SSTA) variability, using a compositing technique for the period 1986-98. The authors describe the extent to which equatorial WWEs are associated with central and eastern equatorial Pacific waveguide warming and...

  • Tropical rainfall predictions from multiple seasonal forecast systems

    A. A. Scaife; L. Ferranti; O. Alves; P. Athanasiadis; J. Baehr; M. Deque; T. Dippe; N. Dunstone; D. Fereday; R. G. Gudgel; R. J. Greatbatch; L. Hermanson; Y. Imada; S. Jain; A. Kumar; C. MacLachlan; W. Merryfield; W.A. Muller; H.-L. Ren; D. Smith; Y. Takaya; G. A. Vecchi; X. Yang
    Journal Article

    e quantify seasonal prediction skill of tropical winter rainfall in 14 climate forecast systems. High levels of seasonal prediction skill exist for year-to-year rainfall variability in all tropical ocean basins. The tropical East Pacific is the most skilful region, with very high correlation scores, and the tropical West Pacific is also highly...

  • Twenty-first-century projections of North Atlantic tropical storms from CMIP5 models

    Gabriele Villarini; Gabriel A. Vecchi
    Journal Article

    Assessing potential changes in North Atlantic (NA) tropical storm (TS) activity this century is of paramount societal and economic significance, and the topic of intense scientific research...

  • The typhoon-induced drying of the Maritime Continent

    Enrico Scoccimarro; Silvio Gualdi; Alessio) Bellucci; Daniele) Peano; Annalisa Cherchi; Gabriel A. Vecchi; Antonio Navarra
    Journal Article

    The Maritime Continent plays a role in the global circulation pattern, due to the energy released by convective condensation over the region which influences the global atmospheric circulation. We demonstrate that tropical cyclones contribute to drying the Maritime Continent atmosphere, influencing the definition of the onset of the dry season...

  • Uncertainties in the timing of unprecedented climates

    E. Hawkins; B. Anderson; N. Diffenbaugh; I. Mahlstein; R. Betts; G. Hegerl; M. Joshi; R. Knutti; D. McNeall; S. Solomon; R. Sutton; J. Syktus; G. Vecchi
    Journal Article

    The question of when the signal of climate change will emerge from the background noise of climate variability—the ‘time of emergence’—is potentially important for adaptation planning. Mora et al....

  • Urbanization exacerbated the rainfall and flooding caused by hurricane Harvey in Houston

    W. Zhang; G. Villarini; G. A. Vecchi; J. A. Smith
    Journal Article

    Category 4 landfalling hurricane Harvey poured more than a metre of rainfall across the heavily populated Houston area, leading to unprecedented flooding and damage. Although studies have focused on the contribution of anthropogenic climate change to this extreme rainfall event...

  • Urbanization exacerbated the rainfall and flooding caused by hurricane Harvey in Houston

    Wei Zhang; Gabriele Villarini; Gabriel A. Vecchi; James A. Smith
    Journal Article

    Category 4 landfalling hurricane Harvey poured more than a metre of rainfall across the heavily populated Houston area, leading to unprecedented flooding and damage. Although studies have focused on the contribution of anthropogenic climate change to this extreme rainfall event1–3, limited attention has been paid to the potential effects of...

  • U.S. Landfalling and North Atlantic Hurricanes: Statistical Modeling of Their Frequencies and Ratios

    Gabriele Villarini; Gabriel A. Vecchi; James A. Smith
    Journal Article

    Time series of U.S. landfalling and North Atlantic hurricane counts and their ratios over the period 1878?2008 are modeled using tropical Atlantic sea surface temperature (SST), tropical mean SST, the North Atlantic Oscillation (NAO), and the Southern Oscillation index (SOI). Two SST input datasets are employed to examine the uncertainties in...

  • On the use of IPCC-class models to assess the impact of climate on Living Marine Resources

    Charles A. Stock; Michael A. Alexander; Nicholas A. Bond; Keith M. Brander; William W.L. Cheung; Enrique N. Curchitser; Thomas L. Delworth; John P. Dunne; Stephen M. Griffies; Melissa A. Haltuch; Jonathan A. Hare; Anne B. Hollowed; Patrick Lehodey; Simon A. Levin; Jason S. Link; Kenneth A. Rose; Ryan R. Rykaczewski; Jorge L. Sarmiento; Ronald J. Stouffer; Franklin B. Schwing; Gabriel A. Vecchi; Francisco E. Werner
    Journal Article

    The study of climate impacts on Living Marine Resources (LMRs) has increased rapidly in recent years with the availability of climate model simulations contributed to the assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Collaboration between climate and LMR scientists and shared understanding of critical challenges...

  • Verification of the skill of numerical weather prediction models in forcasting rainfall from U.S. landfalling tropical cyclones

    B. Luitel; G. Villarini; G. A. Vecchi
    Journal Article

    The goal of this study is the evaluation of the skill of five state-of-the-art numerical weather prediction (NWP) systems [European Centre for Medium-Range Weather Forecasts (ECMWF), UK Met Office (UKMO), National Centers for Environmental Prediction (NCEP), China Meteorological Administration (CMA), and Canadian Meteorological Center (CMC)] in...

  • The vertical distribution of cloud feedback in coupled ocean-atmosphere models

    Brian J. Soden; Gabriel A. Vecchi
    Journal Article

    We assess the vertical distribution of cloud feedbacks in coupled climate models, taking care to distinguish between cloud feedbacks and a change in cloud forcing. We show that the effect of cloud changes on the longwave fluxes provides a strong positive feedback that is broadly consistent across models. In contrast, the effect of cloud changes...

  • Weakening of the North American monsoon with global warming

    S. Pascale; W. R. Boos; S. Bordoni; T. L. Delworth; S. B. Kapnick; H. Murakami; G. A. Vecchi; W. Zhang
    Journal Article

    Future changes in the North American monsoon, a circulation system that brings abundant summer rains to vast areas of the North American Southwest, could have significant consequences for regional water resources. How this monsoon will change with increasing greenhouse gases, however, remains unclear, not least because coarse horizontal...

  • Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing

    Gabriel A. Vecchi; Brian J. Soden; Andrew T. Wittenberg; Isaac M. Held; Ants Leetmaa; Matthew J. Harrison
    Journal Article

    Simple theories suggest that global warming will weaken atmospheric circulation in the tropics during the twenty-first century. Now a reconstruction of atmospheric circulation in the tropical Pacific since the mid-nineteenth century suggests that it has indeed reduced in strength in the past, consistent with both theory and model simulations....

  • A weather-type-based cross-time-scale diagnostic framework for coupled circulation models

    A. G. Munoz; X. Yang; G. A. Vecchi; A. W. Robertson; W. F. Cooke
    Journal Article

    This study proposes an integrated diagnostic framework based on atmospheric circulation regime spatial patterns and frequencies of occurrence to facilitate the identification of model systematic errors across multiple time scales. To illustrate the approach, three sets of 32-yr-long simulations are analyzed for northeastern North America and...

  • Westerly Wind Events in the Tropical Pacific, 1986–95

    D. E. Harrison; Gabriel A. Vecchi
    Journal Article

    Abstract Based on examination of 10 yr of 10-m winds and wind anomalies from European Centre for Medium-Range Weather Forecasts (ECWMF) analysis, definitions for westerly wind events (WWEs) of eight different types are proposed. The authors construct a composite for each type of event, show that a simple propagating Gaussian model...

  • Whither Hurricane Activity?

    Gabriel A. Vecchi; Kyle L. Swanson; Brian J. Soden
    Journal Article

    Alternative interpretations of the relationship between sea surface temperature and hurricane activity imply vastly different future Atlantic hurricane activity.

  • Wind and thermodynamic structures of tropical cyclones in global climate models and their sensitivity to horizontal resolution

    Y. Moon; D. Kim; S. Camarga; A. A. Wing; A. H. Sobel; H. Murakami; K. A. Reed; E. Scoccimarro; G. Vecchi; M. F. Wehner; Zarzycki; M. Zhao
    Journal Article

    Characteristics of tropical cyclones (TCs) in global climate models (GCMs) are known to be influenced by details of the model configurations, including horizontal resolution and parameterization schemes. Understanding model-to-model differences in TC characteristics is a prerequisite for reducing uncertainty in future TC activity projections by...