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Winter crop CO 2 uptake inferred from CONTRAIL measurements over Delhi, India
Author(s) -
Umezawa Taku,
Niwa Yosuke,
Sawa Yousuke,
Machida Toshinobu,
Matsueda Hidekazu
Publication year - 2016
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 - 10.1002/2016gl070939
Subject(s) - environmental science , trace gas , atmospheric sciences , new delhi , metropolitan area , agriculture , climatology , geography , geology , archaeology
Recent studies have shown the impact of expanding agricultural activities on atmospheric CO 2 variations and the global carbon cycle. In this study, we show clear evidence of the measureable impact of Indian wintertime crops (mainly wheat) on the regional carbon budget using high‐frequency atmospheric CO 2 measurements by Comprehensive Observation Network for Trace gases by Airliners (CONTRAIL) over Delhi; this phenomenon is not detected by the existing network of surface CO 2 sites. While a general increase in the vertical profiles of CO 2 toward the ground in the boundary layer was observed throughout December–April, we frequently observed sharp decreases below 2 km during January–March. Seasonal circulations during these 3 months indicated influences from neighboring croplands (with patchy urban areas) located upwind. We conclude that the observed CO 2 decrease is attributable to active uptake by the crops grown in winter and that the uptake exceeds in magnitude the urban CO 2 emissions from the Delhi metropolitan area.