DOI: 10.1007/s00382-012-1617-4
Scopus记录号: 2-s2.0-84884699524
论文题名: Influence of Eurasian snow on Indian summer monsoon in NCEP CFSv2 freerun
作者: Saha S.K. ; Pokhrel S. ; Chaudhari H.S.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2013
卷: 41, 期: 2017-07-08 起始页码: 1801
结束页码: 1815
语种: 英语
英文关键词: Eurasian snow
; Indian summer monsoon
; NCEP CFS
英文摘要: The latest version of the state-of-the-art global land-atmosphere-ocean coupled climate forecast system of NCEP has shown considerable improvement in various aspects of the Indian summer monsoon. However, climatological mean dry bias over the Indian sub-continent is further increased as compared to the previous version. Here we have attempted to link this dry bias with climatological mean bias in the Eurasian winter/spring snow, which is one of the important predictors of the Indian summer monsoon rainfall (ISMR). Simulation of interannual variability of the Eurasian snow and its teleconnection with the ISMR are quite reasonable in the model. Using composite analysis it is shown that a positive snow anomaly, which is comparable to the systematic bias in the model, results into significant decrease in the summer monsoon rainfall over the central India and part of the Equatorial Indian Ocean. Decrease in the summer monsoon rainfall is also found to be linked with weaker northward propagation of intraseasonal oscillation (ISO). A barotropic stationary wave triggered by positive snow anomaly over west Eurasia weakens the upper level monsoon circulation, which in turn reduces the zonal wind shear and hence, weakens the northward propagation of summer monsoon ISOs. A sensitivity experiment by reducing snow fall over Eurasian region causes decrease in winter and spring snow depth, which in turn leads to decrease in Indian summer monsoon rainfall. Results from the sensitivity experiment corroborate with those of composite analysis based on long free run. This study suggests that further improvements in the snow parametrization schemes as well as Arctic sea ice are needed to reduce the Eurasian snow bias during winter/spring, which may reduce the dry bias over Indian sub-continent and hence predictability aspect of the model. © 2012 Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54767
Appears in Collections: 过去全球变化的重建
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作者单位: Indian Institute of Tropical Meteorology, Pune, 411008, India
Recommended Citation:
Saha S.K.,Pokhrel S.,Chaudhari H.S.. Influence of Eurasian snow on Indian summer monsoon in NCEP CFSv2 freerun[J]. Climate Dynamics,2013-01-01,41(2017-07-08)