Extreme local recycling of moisture via wetlands and forests in North-East Indian subcontinent: a Mini-Amazon

• Published in: Scientific reports Vol. 13; no. 1; pp. 521 - 10
• Main Authors: Ganguly, Akash, Oza, Harsh, Padhya, Virendra, Pandey, Amit, Chakra, Swagatika, Deshpande, R D
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 10.01.2023; Nature Publishing Group UK; Nature Portfolio
• Subjects: Convection; Environmental Monitoring; Evaporation; Forests; Monsoons; Precipitation; Rain; Rainfall; Recycling; Seasons; Transpiration; Water availability; Wetlands; Wind
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-27577-5

Moisture recycling in precipitation is an important hydrological process, accounting for ~ 67% globally. North-east India, home to the world's wettest place, boasts vast wetlands and forest-cover. Despite its proximity to the coast, we find locally recycled moisture to be the primary annual source of rainfall (~ 45%). During the pre-monsoon season, the enriched δ O (~ - 0.7 ‰) and high d-excess (~ 14 ‰) are ascribed to enhanced transpiration, owing to atmospheric instability which causes Nor'westers. During the Monsoon season, oceanic flux provides increased surficial moisture, enabling deep-localised convection via evaporation. Significant localised recycling, even during the Monsoon season is estimated (~ 38%), with predominantly high d-excess in precipitation during latter half of the monsoon with increased moisture contribution from floods in Brahmaputra (high d-excess). The increasing δ O and d-excess during the post-monsoon season is associated with progressively lesser rainout history and increased localized recycling (~ 67%). In light of the dwindling wetlands and forest-cover, our study highlights their indispensable role in governing regional hydro-meteorology and water availability.