ANALYSIS OF VARIATION OF RAINFALL TRENDS AND PATTERNS OVER THE INDIAN SUBCONTINENT

Abstract

Rainfall plays a pivotal role in anyregion's agricultural productivity, water resources management, and overall socio-economic development. Hence an understanding of the changing patterns and trends of rainfall is crucial for effective planning, resource allocation, and climate change adaptation strategies. To conduct this study, long-term monthly rainfall for a period of 121 years (1901-2021) from India meteorological department across the Indian subcontinent were collected and analyzed. A detailed analysis of monthly, annual, seasonal and non-seasonal rainfall was carried out. The findings reveal significant changes in rainfall trends and patterns over the Indian subcontinent. Both inter-annual and intra-seasonal variability were observed, highlighting the complex nature of rainfall dynamics in the country. The study also examined the impact of climate phenomena such as El Niño (dry) and La Niña (wet) on the rainfall patterns, emphasizing their influence on the interannual variability using the SPI as an indicator.The yearly SPI analysis revealed that 61 years were wet where the rainfall was more than the normal rainfall out of which 17 years were very wet leading to flood like situations. A more detailed analysis of dry and wet months in the monsoon season was done in order to have an idea regarding the availability of rainfall during the monsoon months for crop planning and irrigation scheduling. All the monsoon months witnessed water scarcity conditions in 50%-60% of the total 121 years’ time period. The results of this research contribute to a better understanding of rainfall dynamics in the Indian subcontinent, aiding scientists, water resource managers, and climate scientists in making informed decisions. Moreover, the findings highlight the need for further research and the development of potent climate models to accurately predict future rainfall trends in the face of climate change.