3:00 PM - 3:15 PM
[AAS12-06] Rabi-crop CO2 uptake inferred from CONTRAIL measurements over Delhi, India
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.