CR 30:13-19 (2005)  -  doi:10.3354/cr030013

Influence of Eurasian snow cover in spring on the Indian Ocean Dipole

Hongxi Pang1,*, Yuanqing He1,2, Aigang Lu1, Jingdong Zhao1, Bo Song1, Baoying Ning1, Lingling Yuan1

1Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, PR China
2Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100029, PR China

ABSTRACT: The Indian Ocean Dipole (IOD) shows a significant negative correlation with the extent of Eurasian snow cover in spring. The anomalies in the land–sea temperature contrast, which are induced by the anomalies of Eurasian snow cover in spring, reverse the patterns of convection activity anomalies over the western and eastern tropical Indian Ocean in summer. Moreover, for heavier and lighter than normal Eurasian snow cover in spring, anomalies in the vertical zonal circulation over the tropical Indian Ocean (Walker circulation) and in the vertical meridional circulation between the Indian Ocean and the Eurasian continent (Hadley circulation) occur in summer. The Walker and Hadley circulation anomalies probably play an important role in the occurrence and duration of IOD events. Eurasian snow cover in spring is presumably one of the factors that trigger IOD events. These results provide a basis for further investigation of the mechanisms linking snow cover, the Indian monsoon, atmospheric circulation, and sea surface temperature.

KEY WORDS: Eurasian snow cover · Indian Ocean Dipole · Ocean–atmosphere coupling · Atmospheric circulation anomalies

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