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The Effect of Monsoon Circulation on the Stable Isotopic Composition of Rainfall
Author(s) -
Midhun M.,
Lekshmy P. R.,
Ramesh R.,
Yoshimura Kei,
Sandeep K. K.,
Kumar Samresh,
Sinha Rajiv,
Singh Ashutosh,
Srivastava Shalivahan
Publication year - 2018
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2017jd027427
Subject(s) - environmental science , climatology , monsoon , moisture , atmospheric sciences , speleothem , bay , east asian monsoon , monsoon of south asia , geology , oceanography , meteorology , geography , archaeology , cave
Understanding the factors that control the variability of oxygen isotopic ratios (δ 18 O) of Indian Summer Monsoon (ISM) rainfall (δ 18 O p ) is of vital importance for the interpretation of δ 18 O p derived from climate proxies (e.g., speleothem and tree ring cellulose) of this region. Here we demonstrate the importance of moisture transport pathways on spatiotemporal variations of ISM δ 18 O p using a new set of daily observations from central and northern India and previously reported data aided by simulations from an isotope‐enabled General Circulation Model. 18 O‐depleted rain events are characterized by a higher number of air parcel back trajectories through the Bay of Bengal branch of moisture transport, while those through the Arabian Sea branch are associated with 18 O enriched rain events. This effect is observed on intraseasonal to interannual timescales in the long‐term observations at New Delhi as well. Thus, the shift in moisture transport regimes must be considered when interpreting δ 18 O p from climate proxies of the ISM region.