THE IMPACT OF LARGE-SCALE ATMOSPHERIC CIRCULATIONS AND ANOMALIES ON INDIAN MONSOON DROUGHTS AND FLOODS AND ON WORLD GRAIN YIELDS - A STATISTICAL-ANALYSIS

large-scale atmospheric circulations and anomalies have been shown to have a significant impact on seasonal weather over many parts of the world. In this paper we have made a statistical analysis of the impact of large-scale atmospheric features such as El Nino/Southern Oscillation (ENSO), stratospheric quasi-biennial wind oscillation (QBO) and Eurasian snow cover on Indian monsoon droughts and floods. The impact of ENSO and Indian monsoon droughts and floods on grain yields has been analyzed statistically by using world-wide grain yield data. It is found that an ENSO event is generally associated with a drought in the Indian monsoon followed by low grain yield over south Asia and Australia and high grain yields over the North-American prairies. Implications of this analysis for estimating world grain yields in advance are considered.