Japan Geoscience Union Meeting 2016

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Symbol A (Atmospheric and Hydrospheric Sciences) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS12] Atmospheric Chemistry

Wed. May 25, 2016 1:45 PM - 3:15 PM 303 (3F)

Convener:*Hitoshi Irie(Center for Environmental Remote Sensing, Chiba University), Toshinobu Machida(National Institute for Environmental Studies), Hiroshi Tanimoto(National Institute for Environmental Studies), Yoko Iwamoto(Faculty of Science Division I, Tokyo University of Science), Chair:Kengo Sudo(Graduate School of Environmental Studies, Nagoya University)

3:00 PM - 3:15 PM

[AAS12-06] Rabi-crop CO2 uptake inferred from CONTRAIL measurements over Delhi, India

*Taku Umezawa1, Yosuke Niwa2, Yousuke Sawa2, Toshinobu Machida1, Hidekazu Matsueda2 (1.National Institute for Environmental Studies, 2.Meteorological Research Institute)

Keywords:CO2, rabi crop, aircraft measurements

Recent studies propose that growing agriculture has altered atmospheric CO2 variations and the global carbon cycle. In this study, we show a clear evidence of significant impact of Indian wintertime (rabi) agriculture (mainly wheat) on the regional carbon budget based on high-frequency atmospheric CO2 measurements onboard commercial airliners over Delhi, India. While a general increasing gradient toward the ground was observed throughout December–April, we have frequently observed sharp decreases near the ground during January–March. In this period, CO2 concentration at altitudes below 2 km was at seasonal stagnation. Meteorology in the season infers influence from neighboring croplands with patchy urban areas located upwind. We conclude that the observed CO2 decrease is attributable to active uptake by rabi-crop growing in the season and that the uptake is comparable in magnitude to urban CO2 emissions from the Delhi metropolitan area.