Climate prediction modelling for northeast monsoon pattern over coastal tamil nadu with global and local parameters

Abstract

Monsoons are abundant seasonal rainfall caused by the consistent seasonal winds that switch their direction with astonishing frequency. The Indian subcontinent receives rainfall from two monsoons, namely the Southwest monsoon and the Northeast monsoon. While the majority of India benefits from the Southwest monsoon, Tamil Nadu and especially the Coastal districts of Tamil Nadu receive a maximum share of its rainfall from the Northeast monsoon. During this season, the coastal community of Tamil Nadu encounters severe cyclonic storms causing floods and the lack of uniform during this season leads to drought. The study focuses on analyzing the inter-annual trend between El Nino Southern Oscillation - Northeast monsoon rainfall as well as ENSO-Southwest monsoon rainfall for the years from 1971-2020. Projection of Northeast monsoon extremities in the Coastal Tamil Nadu till mid-century (2050) was derived from Coupled model inter comparison project phase 5 simulations for Representative Concentration Pathways 4.5 and 8.5 scenarios. The bias-corrected sea surface temperature data from the models were used to calculate the Oceanic Nino Index for the historical period (1971-2020), which was then compared to the observed data. The same is also used for Northeast monsoon extremities validation and evaluation. The dependence of excess and deficit rainfall directly on the El Nino and La Nina events, respectively during the last five decades is evident from the obtained results. Even though a direct relationship exists between El Nino Southern Oscillation and Northeast monsoon rainfall, there are years in which the observed rainfall pattern cannot be explained satisfactorily based on El Nino Southern Oscillation alone. Thus, additional parameters are required to provide a proper explanation for the years during which exceptions occur. newline