1. Tropical and Subtropical Cloud Transitions in Weather and Climate Prediction Models: The GCSS/WGNE Pacific Cross-Section Intercomparison (GPCI)
- Author
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M. J. Miller, Carlos R. Mechoso, Christian Jakob, Paul A. Vaillancourt, Jason C. Cole, I. Meinke, Bodo Ritter, Adrian Lock, Roel Neggers, Johannes Karlsson, C. Ledrian, Burkhardt Rockel, F.J. Turk, Philippe Marquet, M. Bonazzola, William B. Rossow, S. Cardoso, David A. Randall, A. von Engeln, Hua-Lu Pan, Martin Köhler, H. Kitagawa, Jui-Lin Li, Anthony D. DelGenio, Y. Jiao, Ming Zhao, A. P. Siebesma, Dmitrii Mironov, João Paulo Teixeira, Pedro M. A. Miranda, Charmaine Franklin, Erik van Meijgaard, João P. A. Martins, Cecile Hannay, Charlotte A. DeMott, Pedro M. M. Soares, Akira Kuwano-Yoshida, Philip J. Rasch, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Instituto Dom Luis, University of Lisbon, Lisbon, Portugal, National Center for Atmospheric Research [Boulder] (NCAR), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Canadian Centre for Climate Modelling and Analysis (CCCma), Environment and Climate Change Canada, NASA Goddard Institute for Space Studies (GISS), NASA Goddard Space Flight Center (GSFC), Department of Atmospheric Science [Fort Collins], Colorado State University [Fort Collins] (CSU), Centre for Australian Weather and Climate Research (CAWCR), Monash University [Melbourne], Stockholm University, Japan Meteorological Agency (JMA), European Centre for Medium-Range Weather Forecasts (ECMWF), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), United Kingdom Meteorological Office, Exeter, United Kingdom, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric and Oceanic Sciences [Los Angeles] (AOS), University of California [Los Angeles] (UCLA), University of California (UC)-University of California (UC), Koninklijk Nederlands Meteorologisch Instituut, De Bilt, Netherlands, Experimental Climate Prediction Center [San Diego], University of California [San Diego] (UC San Diego), Research and Development Division, Deutscher Wetterdienst, Offenbach, Germany, NCEP Environmental Modeling Center (EMC), NOAA National Centers for Environmental Prediction (NCEP), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA), Pacific Northwest National Laboratory (PNNL), Institute for Coastal Research, GKSS Research Centre, Geesthacht, Germany, City College of New York [CUNY] (CCNY), City University of New York [New York] (CUNY), Canadian Meteorological Centre (CMC), European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), NOAA Geophysical Fluid Dynamics Laboratory (GFDL), National Oceanic and Atmospheric Administration (NOAA), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), University of California-University of California, and CREST, The City College of New York, New York, NY, United States
- Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,Convection ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,Meteorology ,Cloud cover ,Weather forecasting ,Tropics ,Cloud physics ,Weather and climate ,Subtropics ,010502 geochemistry & geophysics ,computer.software_genre ,01 natural sciences ,[SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology ,13. Climate action ,Climatology ,ddc:551 ,Environmental science ,computer ,Physics::Atmospheric and Oceanic Physics ,0105 earth and related environmental sciences ,Global Energy and Water Cycle Experiment - Abstract
A model evaluation approach is proposed in which weather and climate prediction models are analyzed along a Pacific Ocean cross section, from the stratocumulus regions off the coast of California, across the shallow convection dominated trade winds, to the deep convection regions of the ITCZ—the Global Energy and Water Cycle Experiment Cloud System Study/Working Group on Numerical Experimentation (GCSS/WGNE) Pacific Cross-Section Intercomparison (GPCI). The main goal of GPCI is to evaluate and help understand and improve the representation of tropical and subtropical cloud processes in weather and climate prediction models. In this paper, a detailed analysis of cloud regime transitions along the cross section from the subtropics to the tropics for the season June–July–August of 1998 is presented. This GPCI study confirms many of the typical weather and climate prediction model problems in the representation of clouds: underestimation of clouds in the stratocumulus regime by most models with the corresponding consequences in terms of shortwave radiation biases; overestimation of clouds by the 40-yr ECMWF Re-Analysis (ERA-40) in the deep tropics (in particular) with the corresponding impact in the outgoing longwave radiation; large spread between the different models in terms of cloud cover, liquid water path and shortwave radiation; significant differences between the models in terms of vertical cross sections of cloud properties (in particular), vertical velocity, and relative humidity. An alternative analysis of cloud cover mean statistics is proposed where sharp gradients in cloud cover along the GPCI transect are taken into account. This analysis shows that the negative cloud bias of some models and ERA-40 in the stratocumulus regions [as compared to the first International Satellite Cloud Climatology Project (ISCCP)] is associated not only with lower values of cloud cover in these regimes, but also with a stratocumulus-to-cumulus transition that occurs too early along the trade wind Lagrangian trajectory. Histograms of cloud cover along the cross section differ significantly between models. Some models exhibit a quasi-bimodal structure with cloud cover being either very large (close to 100%) or very small, while other models show a more continuous transition. The ISCCP observations suggest that reality is in-between these two extreme examples. These different patterns reflect the diverse nature of the cloud, boundary layer, and convection parameterizations in the participating weather and climate prediction models.
- Published
- 2011
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