Influence of El Nino/southern oscillation, Pacific decadal oscillation, and local sea-surface temperature anomalies on peak season monsoon precipitation in India

摘要

Many modeling and empirical studies have revealed that summer monsoon precipitation in India is significantly affected by El Nino/Southern Oscillation (ENSO) as well as by sea-surface temperatures (SSTs) in the Arabian Sea, Bay of Bengal, and Indian Ocean. Recently, the impact of the Pacific decadal oscillation (PDO) on Indian rainfall has been the focus of research. In this investigation, we collect monthly rainfall data for 18 grid cells covering India and develop statistical indices of ENSO, PDO, and local SSTs over the period 1925-1998. We find that ENSO reduces precipitation in southern India while having a small impact over most of the country. The PDO appears to amplify the ENSO signal in southern India, while local SSTs were directly related to monsoon precipitation totals in the southern peninsula region. While the associations are often statistically significant, the combination of ENSO, PDO, and SSTs explains less than 20% of the variance in monsoon rainfall throughout India. [References: 39]