Spatial variability of ENSO-based monsoon rainfall in the coastal region of southeastern India

ABSTRACT

Climate variability during El Niño and La Niña events is believed to synch with the monsoon fluctuation globally. Studying these phenomena is crucial for predicting meteorological factors like temperature and precipitation. This study investigates the spatial variability of southwest monsoon rainfall (SMR) due to El Niño and La Niña on the southeastern coast of India. Monthly average rainfall data for the coastal districts of Tamil Nadu, Andhra Pradesh, and Odisha from 1970 to 2020 were analyzed. The analysis revealed that the El Niño Southern Oscillation (ENSO) had a distinct impression on these districts. Results showed that during El Niño, Tamil Nadu and Andhra Pradesh received below-normal rainfall with an 82% probability, while above-normal rainfall occurred during La Niña, with probabilities of 65 and 70%, respectively. In Odisha, the probability of below-normal rainfall during El Niño is 41%, and above-normal rainfall during La Niña was 40%. However, the impact on Odisha was insignificant and did not align with conventional ENSO patterns. This study improves understanding of rainfall variability along the southeastern coast of India, highlighting the need for regional climate forecasting. These insights can aid policymakers in developing drought management and flood preparedness strategies, providing a valuable resource for enhancing climate prediction models.