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Topics in 2016



Winter-crop CO2 uptake found over Delhi, India

An edited version of this paper was published by AGU. Copyright (2016) American Geophysical Union.

Recent studies have shown the impact of expanding agricultural activities on atmospheric CO2 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 CO2 measurements by Comprehensive Observation Network for Trace gases by Airliners (CONTRAIL) over Delhi; this phenomenon is not detected by the existing network of surface CO2 sites. While a general increase in the vertical profiles of CO2 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 CO2 decrease is attributable to active uptake by the crops grown in winter and that the uptake exceeds in magnitude the urban CO2 emissions from the Delhi metropolitan area.


Examples of CO2 vertical profiles over DEL for flights when (a) a decrease and (b) an increase toward the ground were observed. Red lines are spline fits to the measurements. Also shown are profiles of potential temperature (light blue, top axis). The estimated CBL height is shown as the horizontal dashed line and the data points below and above it are colored in black and gray, respectively.


Reference



JpSAC Young Researcher Award for Dr. Yosuke Niwa

Dr. Yosuke Niwa was awarded for the 12th Yound Researcher Award from the Japan Society of Atmospehric Chemistry (JpSAC) for his outstanding research on inversion analysis of CO2 Flux based on the global atmospheric transport model NICAM-TM. The award was presented at the 2016 annual JpSAC meeting in Sapporo, Japan.