Spatial variability of north east monsoon rainfall over Peninsular India during strong, weak and normal NEMR years

摘要

North East Monsoon Rainfall (NEMR) is classified as strong, weak and normal depending on the strength of the NEM rainfall using Peninsular India (PI) monthly rainfall data and its behavior is examined during contrasting NEMR years. The sub divisions Kerala, Tamil Nadu and Coastal Andhra Pradesh contribute maximum rainfall to the cumulative PI NEMR and South Interior Karnataka and Rayalseema contribute the least, whether it is a strong or weak NEM. Analysis shows that the rainfall pattern is substantially different in all six sub divisions between strong and weak NEMR years and the difference is statistically significant as confirmed by the Wilcoxon Mann-Whitney rank sum test. Composite analysis shows that more rainfall is received in all the six sub divisions in comparison to the Long Period Average (LPA) during years of strong NEMR, and vice-versa during years of weak NEMR. Correlation analysis between PI NEMR and the sub divisional NEMR indicates that the sub divisions Tamil Nadu (TLN), Rayalseema (RLS), South Interior Karnataka (SIK) and Coastal Andhra Pradesh (CAP) have strong positive correlation whereas Kerala (KER) and Coastal Karnataka (COK) rainfall shows moderate correlation.