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Stable isotope evidence for moisture sources in the asian summer monsoon under present and past climate regimes
Author(s) -
Aggarwal Pradeep K.,
Fröhlich Klaus,
Kulkarni Kshitij M.,
Gourcy Laurence L.
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl019911
Subject(s) - precipitation , climatology , intertropical convergence zone , moisture , monsoon , environmental science , range (aeronautics) , east asian monsoon , water content , isotope , stable isotope ratio , longitude , geology , atmospheric sciences , latitude , geography , meteorology , materials science , composite material , physics , geotechnical engineering , geodesy , quantum mechanics
Stable isotope compositions of present day precipitation in the 70°E–160°W longitude range reveal a strong correlation with moisture source and transport patterns and are not correlated with the amount of precipitation, contrary to existing interpretations. Spatially and temporally variable moisture sources and cyclonic circulation result in more depleted isotope values (δ 18 O ∼ −5 to −7‰) in the 100°E–170°E range. Oceanic moisture with minimal continental loss or input results in comparatively enriched δ 18 O values (∼−2 to −4‰) in the 70°E–100°E range and east of 170°E. Isotope compositions of dated groundwater archives from the Philippines, Vietnam, Thailand and Bangladesh, reflecting past isotopic composition of precipitation, indicate that this distinction in moisture regimes was preserved during the last glacial period and strongly suggest that there was no significant shift in the summer Inter‐Tropical Convergence Zone (ITCZ) in this region.