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Communication incl. Poster: BibTeX citation key:  DjiotangTchotchou
Djiotang Tchotchou, L. A. & Mkankam Kamga, F. 2009. Sensitivity of the simulated African Monsoons of summer 1993 to convective parameterization schemes in RegCM3. Work presented at Third International AMMA Conference, July 20—24, at Ouagadougou, Burkina Faso.
Added by: roussot 2009-11-05 13:57:33
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Categories: Monsoon system and its variability, Weather to Climatic modelling and forecasting
Keywords: Clouds - Convection, Modelling
Creators: Djiotang Tchotchou, Mkankam Kamga
Publisher: African Monsoon Multidisciplinary Analyses (Ouagadougou, Burkina Faso)
Collection: Third International AMMA Conference

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Abstract
In this study, the International Center for Theoretical Physics Regional Climate Model version (RegCM3) was used to simulate the African summer monsoon during the rainy season 1993. Four different convection and cumulus parameterization schemes of Anthes Kuo (AK), Grell and Fristish Chappell (GFC), Grell and Arakawa Schubert (GAS) and MIT-Emmanuel (EM) were used to study the sensitivity of monsoon to cumulus effects. The model was integrated from a period of five months, starting from 1 May 1993 to 30 September 1993 using the European Centre for Medium-Range-Weather Forecast (ECMWF) Reanalysis data ( ERA40) as input boundary conditions. The 6 hourly reanalysis data were used to provide the lateral boundary conditions, and the observed weekly Reynolds Sea Surface Temperature interpolated to 6h was used as the lower boundary forcing. The results show that GFC and EM schemes were able to capture the diurnal cycle of precipitation and the zonal averages of stratiform rain fraction as observe in Tropical Rainfall Measuring Mission (TRMM) although there was overestimation of rainfall amount. GAS and AK have patched rainfall patterns over continental areas as opposed to the observed zonal pattern. However, the spatial distribution of rainfall was found to be shifted about 3°– 5° northward for all schemes and its quantity was different in all the schemes. The AK scheme underestimated the rainfall. The GAS scheme captures well the maximum as shown by observation. The GFC and EM schemes reproduce well the rainband although theirs overestimations amount. It was found that the northward shift of the rainband is accompanied by the northward shift of the African Easterly Jet (AEJ). Simulated rainfall and AEJ position depend on the soil moisture via soil albedo.
Added by: roussot