Association of the Indian summer monsoon rainfall variability with the geophysical parameters over the Arctic region



A study is carried out to understand whether the Indian summer monsoon rainfall variability is associated with the geophysical parameters over the Arctic region. The correlation analyses of the satellite-derived sea ice data for 29 years indicate that out of 9 sectors of the Arctic region, the Kara and Barents Seas sector's Sea Ice Extent (KBS SIE) during October has a strong relationship with the All-India Summer Monsoon Rainfall (AISMR) in the following year. This relationship is more pronounced for the extreme cases, which are identified as the drought or the excess monsoon years. Moreover, the composites of certain geophysical parameters over the Arctic also behave in tandem with the monsoon rainfall. In order to test the relationship of these geophysical parameters with the monsoon rainfall, a case of the recent drought of 2009 is independently evaluated. The results obtained in this study bring out that KBS SIE and some other parameters of the Arctic region can be used as potential predictors in the long-range forecasting of AISMR with a lead period of more than six months. A table indicating the qualitative forecast of the monsoon rainfall is presented on the basis of some parameters of the Arctic region. The mean sea level pressure anomaly tendency over northwest Europe during winter, which is one of the predictors used for forecasting the AISMR, is significantly correlated with the KBS SIE during the preceding October. As such, with the knowledge of October KBS SIE, this parameter can also be foreseen a few months in advance. Copyright © 2011 Royal Meteorological Society