Interannual Indian rainfall variability and Indian ocean sea surface temperature anomalies

Gabriel Andres Vecchi, D. E. Harrison

Research output: Chapter in Book/Report/Conference proceedingChapter

49 Scopus citations

Abstract

It is shown that interannual variations in Indian continental rainfall during the southwest monsoon can be usefully represented by two regional rainfall indices. Indian rainfall is concentrated in two regions, each with strong mean and variance in precipitation: the Western Ghats (WG) and the Ganges-Mahanadi Basin (GB) region. Interannual variability of rainfall averaged over each of the two regions (WG and GB) is uncorrelated; however, the rainfall over these two regions together explains 90% of the interannual variance of All-India rainfall (AIR). The lack of correlation between WG and GB rainfall suggests that different mechanisms may account for their variability. During the period 1982-2001, rainfall variability over each of these two regions exhibits distinct relationships to Indian Ocean SST: warm SSTA over the western Arabian Sea at the monsoon onset is associated with increased WG rainfall (r = 0.77), while cool SSTA off of Java and Sumatra is associated with increased GB rainfall (r = −0.55). The connection between SSTA and AIR is considerably weaker, and represents the superposition of that associated with each region. We find the relationship with WG rainfall is robust, while that with GB results from a single exceptional year. Each region also exhibits distinct relationships to El Niño SSTA indices.

Original languageEnglish (US)
Title of host publicationEarth?s Climate
Subtitle of host publicationThe Ocean-Atmosphere Interaction, 2004
EditorsS.P. Xie, J.A. Carton, C. Wang
PublisherBlackwell Publishing Ltd.
Pages247-259
Number of pages13
ISBN (Electronic)9781118665947
ISBN (Print)9780875904122
DOIs
StatePublished - Jan 1 2004

Publication series

NameGeophysical Monograph Series
Volume147
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779

All Science Journal Classification (ASJC) codes

  • Geophysics

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