Evaluation of the distribution of subtropical free tropospherichumidity in AMIP-2 simulations using METEOSAT water vaporchannel data

• Published in: Geophysical Research Letters
• Main Authors: Brogniez, Hélène, Roca, Rémy, Picon, Laurence
• Other Authors: Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2005
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; South Atlantic Ocean
• Online Access: https://hal.science/hal-00159814; https://hal.science/hal-00159814/document; https://hal.science/hal-00159814/file/Brogniez_et_al-2005-Geophysical_Research_Letters-2.pdf; https://doi.org/10.1029/2005GL024341

In the framework of the Atmospheric ModelIntercomparison Project (AMIP) phase 2, we haveestablished a diagnostic of the free tropospheric humidity(FTH) distribution using METEOSAT data over the 1984–1995 period for 14 climate models. The methodology ofevaluation follows a two step ‘‘model-to-satellite’’ approach.First the raw METEOSAT ‘‘Water Vapor’’ radiances aresimulated from the model profiles of temperature andhumidity using the RTTOV-7 radiative transfer model.Second, the radiances are converted into FTH using thesame coefficients as in the satellite product offering a directcomparison. The analysis is focused on the dry subtropicalareas observed by METEOSAT: the Eastern Mediterraneanand the tropical South Atlantic Ocean. Most of the modelsreproduce the observed seasonal cycle both in terms ofphasing and magnitude, despite an overall moist bias. A fewmodels are in close agreement with the satellite data. Themagnitude of the satellite estimated inter-annual variability isalso generally captured by models. Again, a small subsetof models shows close agreement with the observations.This comparison suggests general improvements of themodels with respect to the AMIP-1 simulations.