Publication
Controls on Stable Water Isotopes in Monsoonal Precipitation Across the Bay of Bengal: Atmosphere and Surface Analysis
Publisher:
American Geophysical Union (AGU)
Date:
07-03-2023
DOI:
10.1029/2022GL102229
Abstract: Stable hydrogen isotopes in monsoonal precipitation (δD p ) at three sites (Port Blair, Barisal and Darjeeling) reveal the factors governing δD p variations over a south‐north gradient across the Bay of Bengal. We found that the δD p at each site continuously decreases from May to September and these trends become more pronounced from south to north. The decreasing trends of downstream δD p closely follow the decreasing trends of upstream stable hydrogen isotopes in water vapor (δD v ), which indicates that upstream δD v properties shape initial spatiotemporal patterns of the downstream δD p (“shaping effect”). Additionally, our results demonstrate that, during moisture transport, upstream vertical air motions (convection and downward motion) and topographic relief magnify the litude of the decreasing trends of downstream δD p (“magnifying effect”). Our findings imply that upstream δD v properties and relevant atmospheric and topographical conditions along the moisture transport pathway need to be considered collectively to better interpret paleoclimate records.