Observed rainfall changes in the past century (1901-2019) over the wettest place on Earth

• Published in: Environmental research letters Vol. 16; no. 2; pp. 24018 - 24031
• Main Authors: Kuttippurath, J, Murasingh, S, Stott, P A, Sarojini, B Balan, Jha, Madan K, Kumar, P, Nair, P J, Varikoden, H, Raj, S, Francis, P A, Pandey, P C
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.02.2021
• Subjects: Agricultural production; Annual rainfall; Climate change; climate indices; Drinking behavior; Drinking water; Environmental impact; Groundwater; Groundwater runoff; Human influences; Land cover; Land use; land use and land cover; monsoon rainfall; Ocean temperature; Rain gauges; Rainfall; rainfall analysis; Rainfall measurement; Resource management; Runoff; Soil moisture; Surface runoff; trend detection; Water resources; India
• ISSN: 1748-9326; 1748-9326
• DOI: 10.1088/1748-9326/abcf78

Changes in rainfall affect drinking water, river and surface runoff, soil moisture, groundwater reserve, electricity generation, agriculture production and ultimately the economy of a country. Trends in rainfall, therefore, are important for examining the impact of climate change on water resources for its planning and management. Here, as analysed from 119 years of rainfall measurements at 16 different rain gauge stations across northeast India, a significant change in the rainfall pattern is evident after the year 1973, with a decreasing trend in rainfall of about 0.42 ± 0.024 mm dec−1. The wettest place of the world has shifted from Cherrapunji (CHE) to Mawsynram (MAW) (separated by 15 km) in recent decades, consistent with long-term rainfall changes in the region. The annual mean accumulated rainfall was about 12 550 mm at MAW and 11 963 mm at CHE for the period 1989-2010, as deduced from the available measurements at MAW. The changes in the Indian Ocean temperature have a profound effect on the rainfall in the region, and the contribution from the Arabian Sea temperature and moisture is remarkable in this respect, as analysed with a multivariate regression procedure for the period 1973-2019. The changes in land cover are another important aspect of this shift in rainfall pattern, as we find a noticeable reduction in vegetation area in northeast India in the past two decades, implying the human influence on recent climate change.