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Role of Antarctic circumpolar wave in modulating the extremes of Indian summer monsoon rainfall

Prabhu, A and Mahajan, PN and Khaladkar, RM and Chipade, MD (2010) Role of Antarctic circumpolar wave in modulating the extremes of Indian summer monsoon rainfall. Geophysical Research Letters, 37 (14).

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Sea ice extent (SIE) over different sectors of Antarctica displays intra-seasonal and inter-annual variability. It is reflected in different atmospheric and oceanic parameters, which are characterized as the manifestation of Antarctic circumpolar wave (ACW). Due to its large areal extent, ACW is linked to the global climate. Another global phenomenon, which is instrumental for the well being of vast population of the Asian sub-continent, is the Indian summer monsoon season (June-September). The quantum of all India summer monsoon rainfall (AISMR) received during the season decides the overall economic health of the country with the extremes causing disastrous situation, in either way. In the present study, the cases of the excess monsoon and drought years of the recent decades are considered to determine the possible role played by the ACW in influencing the monsoon rainfall. The correlation analyses, carried out for a period of 26 years from 1980 to 2005, show that the SIE over the Bellingshausen and Amundsen Sea Sector (BASS) during the austral summer (October-December) has an inverse relationship with the AISMR of the following year. Further, it is revealed that the sea surface temperature and the upper tropospheric meridional transport of heat over the southeast Pacific, during the period preceding the monsoon season, show contrasting behavior with respect to the extremes of AISMR. These parameters bring out the role of both the oceanic and the atmospheric modes of the ACW in modulating the AISMR. The study has a potential application in forecasting of the monsoon rainfall a few months in advance.

Item Type: Article
Additional Information: Copyright of this article belongs to American Geophysical Union
Uncontrolled Keywords: Amundsen Sea; Antarctic circumpolar wave; Antarctica; Austral summers; Correlation analysis; Global climates; Indian summer monsoon; Indian summer monsoon rainfall; Interannual variability; Inverse relationship; Meridional transport; Monsoon rainfall; Monsoon season; Oceanic parameters; Potential applications; Sea ice extent; Sea surface temperatures; Summer monsoon rainfall; Well being, Atmospheric temperature; Oceanography; Rain; Sea ice; Weather forecasting, Atmospheric thermodynamics, annual variation; Antarctic Circumpolar Wave; correlation; drought; meridional circulation; monsoon; rainfall; sea ice; sea surface temperature; troposphere; weather forecasting, Amundsen Sea; Bellingshausen Sea; Southern Ocean
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 29 May 2015 09:20
Last Modified: 29 May 2015 09:20

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