The Indian summer monsoon rainfall (ISMR) during June to September contributes most of the annual rainfall over India and plays an important role in Indian agriculture and thus the economy. It exhibits high spatio-temporal variabilities forced from both internal and external factors, which are important for better understanding and prediction of ISMR. Since the internal factors, mainly in the form of intraseasonal oscillations set a limit to the predictability, the major focus is given to the external forcing factors including the coupled air–sea interactions, sea surface temperature variations, snow cover, etc. This paper mainly aims to review the results of recent research analysis on ISMR variability and the major climate factors that determine the variability. Focus is given on the contributions from the coupled ocean–atmosphere processes in the Indian and Pacific Oceans to the ISMR variability [(primarily the El Niño Southern Oscillation (ENSO)] and Indian Ocean Dipole (IOD). Several studies were carried out in recent decades to explore the ISMR variabilities and their influences from tropical oceans. The studies, which focused the impact of ENSO and IOD on the ISMR variability have been considered in exploring their relationships and observed changes in recent decades. In the backdrop of varying relationship of ISMR with ENSO and IOD in the regional scale, it is important to study further the regional teleconnection of ISMR variabilities with oceanic factors, especially from the Indian and Pacific Ocean basin.

中文翻译：

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印度夏季风降雨量、变率及其与 ENSO 和 IOD 关系的综述

6 月至 9 月期间的印度夏季风降雨量 (ISMR) 占印度全年降雨量的大部分，对印度农业乃至经济发挥着重要作用。它表现出受内部和外部因素影响的高时空变异性，这对于更好地理解和预测 ISMR 很重要。由于内部因素，主要以季节内振荡的形式限制了可预测性，主要关注外部强迫因素，包括海气耦合、海面温度变化、积雪等。 本文主要旨在回顾最近关于 ISMR 变异性和决定变异性的主要气候因素的研究分析结果。