10:45 AM - 11:00 AM
[AAS04-07] Methane emission estimate from South Asia: AMASA project
Keywords:methane, greenhose gas, Asia
GOSAT is the first satellite that is dedicated to greenhouse-gas-monitoring. The onboard Sensor TANSO-FTS (Fourier Transform Spectrometer) is designed to measure CO2 and CH4. GOSAT has collected data for about 8 years, and validation studies revealed sufficient reliability of GOSAT data for CH4 cycling in the Earth’s environment (e.g., Morino et al., 2011, Inoue et al., 2014, Ono et al., 2015). The essential merit of satellite observation is wide spatial coverage. We found very high concentrations of CH4 over Asia in GOSAT data, which seem to be connected to the high CH4 emissions from this region. However, the connection is not straightforward because of complicated transport mechanisms. In particular, at the foothills of Himalaya Mountains, upwelling wind lift the CH4 up to mid- and upper-troposphere during the monsoon season, resulting in the high columnar concentrations that can be observed from GOSAT (Chandra et al., 2017, paper in preparation). We are also conducting field measurements of atmospheric CH4 at ground-based stations in Karnal, Sonepat, Nainital, and Comilla. Combined use of those satellite-based and ground-based measurements can give us spatial structure of CH4 distribution, which would improve the emission estimate using an inverse analysis system.
To develop an emission mitigation proposal, we are conducting rice field experiments at the Tamilnadu Rice Research Institute, India by managing rice cultivars, water table and soil properties. The preliminary results suggest that CH4 emission from rice cultivation can be reduced by half when applying proper cultivation managements. Based on these new findings, we are pursuing an appropriate mitigation proposal to reduce CH4 emissions from South Asia.
Ono, A. et al., Comparison of GOSAT SWIR and Aircraft Measurements of XCH4 over West Siberia,
SOLA, 11, 160-164, doi:10.2151/sola.2015-036, 2015.
Inoue, M. et al., Validation of XCH4 derived from SWIR spectra of GOSAT TANSO-FTS with aircraft measurement data, Atmos. Meas. Tech., 7, 2987-3005, doi:10.5194/amt-7-2987-2014, 2014.
Morino, I. et al.: Preliminary validation of column-averaged volume mixing ratios of carbon dioxide and methane retrieved from GOSAT short-wavelength infrared spectra, Atmos. Meas. Tech., 4, 1061-1076, doi:10.5194/amt-4-1061-2011, 2011.