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| Titel |
Short-term Variability of Indian Summer Monsoon Rainfall δ18O |
| VerfasserIn |
Midhun Madhavan, Lekshmy Palliyil Ravisankar, Ramesh Rengaswamy |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250106800
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| Publikation (Nr.) |
 EGU/EGU2015-6477.pdf |
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| Zusammenfassung |
| We present the first ever dataset of rainfall stable isotopologues (δ18O and δD) of Indian
Summer Monsoon with a high spatio-temporal resolution. ~260 daily rain samples were
collected from six different locations over Central and Northern India during June to
September (monsoon season), 2013. On a daily scale, significant linear negative correlations
between rainfall amount and its δ18O (“amount effect”) are observed at five out of six
locations, however the amount explains only ~7-23 % of total observed variability of daily
rainfall δ18O. There are two different moisture transport pathways to Central and
Northern India during the summer monsoon; the Arabian Sea and the Bay of Bengal
Branches. HYSPLIT back trajectory analysis suggests that the Arabian Sea component
is stronger during relatively enriched δ18O rain events compared δ18O depleted
rain events. A significant negative temporal trend in rainfall δ18O is observed at
four stations during the season. This is likely due to the shift in moisture transport
pathway from the Arabian Sea branch to the Bay of Bengal branch during the later
period of the season. These results suggest that δ18O of Indian Summer Monsoon
rainfall is highly sensitive to the circulation pattern. The new dataset will be useful to
validating isotope enabled General Circulation Models over Indian Monsoon region. |
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