DOI: 10.1007/s00382-015-2880-y
Scopus记录号: 2-s2.0-84946771991
论文题名: Downscaling GISS ModelE boreal summer climate over Africa
作者: Druyan L.M. ; Fulakeza M.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 47, 期: 11 起始页码: 3499
结束页码: 3515
语种: 英语
英文关键词: Dynamic downscaling
; Regional climate models
; West African monsoon
英文摘要: The study examines the perceived added value of downscaling atmosphere–ocean global climate model simulations over Africa and adjacent oceans by a nested regional climate model. NASA/Goddard Institute for Space Studies (GISS) coupled ModelE simulations for June–September 1998–2002 are used to form lateral boundary conditions for synchronous simulations by the GISS RM3 regional climate model. The ModelE computational grid spacing is 2° latitude by 2.5° longitude and the RM3 grid spacing is 0.44°. ModelE precipitation climatology for June–September 1998–2002 is shown to be a good proxy for 30-year means so results based on the 5-year sample are presumed to be generally representative. Comparison with observational evidence shows several discrepancies in ModelE configuration of the boreal summer inter-tropical convergence zone (ITCZ). One glaring shortcoming is that ModelE simulations do not advance the West African rain band northward during the summer to represent monsoon precipitation onset over the Sahel. Results for 1998–2002 show that onset simulation is an important added value produced by downscaling with RM3. ModelE Eastern South Atlantic Ocean computed sea-surface temperatures (SST) are some 4 K warmer than reanalysis, contributing to large positive biases in overlying surface air temperatures (Tsfc). ModelE Tsfc are also too warm over most of Africa. RM3 downscaling somewhat mitigates the magnitude of Tsfc biases over the African continent, it eliminates the ModelE double ITCZ over the Atlantic and it produces more realistic orographic precipitation maxima. Parallel ModelE and RM3 simulations with observed SST forcing (in place of the predicted ocean) lower Tsfc errors but have mixed impacts on circulation and precipitation biases. Downscaling improvements of the meridional movement of the rain band over West Africa and the configuration of orographic precipitation maxima are realized irrespective of the SST biases. © 2015, Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53437
Appears in Collections: 过去全球变化的重建
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作者单位: NASA/Goddard Institute for Space Studies, 2880 Broadway, New York, NY, United States; Department of Applied Physics and Math, Columbia University, 2880 Broadway, New York, NY, United States; Center for Climate Systems Research, Columbia University, 2880 Broadway, New York, NY, United States
Recommended Citation:
Druyan L.M.,Fulakeza M.. Downscaling GISS ModelE boreal summer climate over Africa[J]. Climate Dynamics,2016-01-01,47(11)