Julia Sander, Matthew Garvert, E. Orlandi, Patricia de Rosnay, Federico Fierli, Christophe Peugeot, Mathieu Nuret, Françoise Guichard, Olivier Bock, Philip P. Harris, Bertrand Decharme, Xuefeng Cui, Gianpaolo Balsamo, Aaron Boone, Jean-Luc Redelsperger, Nicole Asencio, Jean-Philippe Lafore, Andrew P. Morse, J.-C. Bergès, Sarah C. Jones, Miguel Ángel Gaertner, Benjamin Lamptey, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Hydrosciences Montpellier (HSM), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), LAboratoire de Recherche en Géodésie (LAREG), Ecole nationale des sciences géographiques (ENSG), Institut géographique national [IGN] (IGN)-Institut géographique national [IGN] (IGN), University of Liverpool, Universidad de Castilla-La Mancha (UCLM), National Center for Atmospheric Research [Boulder] (NCAR), Università degli Studi di Ferrara (UniFE), Institute for Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Istituto di Scienze dell'Atmosfera e del Clima (ISAC), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Centre for Medium-Range Weather Forecasts (ECMWF), Centre for Ecology and Hydrology (CEH), Natural Environment Research Council (NERC), Pôle de recherche pour l'organisation et la diffusion de l'information géographique (PRODIG (UMR_8586 / UMR_D_215 / UM_115)), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-AgroParisTech-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Météo France-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Ecoles nationale des sciences géographiques (ENSG), University of Ferrara [Ferrara], Institut für Meteorologie und Klimaforschung (IMK), Karlsruher Institut für Technologie (KIT), Institut de Recherche pour le Développement (IRD)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Université Panthéon-Sorbonne (UP1)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), 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), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universidad de Castilla-La Mancha = University of Castilla-La Mancha (UCLM), Università degli Studi di Ferrara = University of Ferrara (UniFE), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)
An evaluation of precipitation and evapotranspiration simulated by mesoscale models is carried out within the African Monsoon Multidisciplinary Analysis (AMMA) program. Six models performed simulations of a mesoscale convective system (MCS) observed to cross part of West Africa in August 2005. Initial and boundary conditions are found to significantly control the locations of rainfall at synoptic scales as simulated with either mesoscale or global models. When initialized and forced at their boundaries by the same analysis, all models forecast a westward-moving rainfall structure, as observed by satellite products. However, rainfall is also forecast at other locations where none was observed, and the nighttime northward propagation of rainfall is not well reproduced. There is a wide spread in the rainfall rates across simulations, but also among satellite products. The range of simulated meridional fluctuations of evapotranspiration (E) appears reasonable, but E displays an overly strong zonal symmetry. Offline land surface modeling and surface energy budget considerations show that errors in the simulated E are not simply related to errors in the surface evaporative fraction, and involve the significant impact of cloud cover on the incoming surface shortwave flux. The use of higher horizontal resolution (a few km) enhances the variability of precipitation, evapotranspiration, and precipitable water (PW) at the mesoscale. It also leads to a weakening of the daytime precipitation, less evapotranspiration, and smaller PW amounts. The simulated MCS propagates farther northward and somewhat faster within an overall drier atmosphere. These changes are associated with a strengthening of the links between PW and precipitation.