We have analyzed the column-averaged CH4 concentration (xCH4) using scanning imaging absorption spectrometer for atmospheric chartography (SCIAMACHY) and compared the data with the bottom-up emission inventory datasets and other satellite-derived indices such as the land-surface water coverage (LSWC) and the normalized difference vegetation index (NDVI). The geographical distribution of high CH4 values corresponds to strong emissions from regions where rice is cultivated, as indicated in the inventory maps. The Pearson’s correlation coefficients (r) between xCH4 and the rice emission inventory data are observed to be greater than ~0.6 over typical rice fields, with outstanding r-values of ~0.8 in the Ganges Basin and the Sichuan Basin. This suggests that the emission of CH4 from rice cultivation mainly controls the seasonality of the CH4 concentration over such regions. The correlation between xCH4 and LSWC and NDVI are also as large as 0.6. In Southeast Asia, the r-values of xCH4 with bottom-up inventory data that includes all categories are not as high as those with the emission, as estimated from the rice category only. This is indicative of the relative importance of rice emissions among all other emission categories in Southeast Asia.
In addition, I would like to introduce our research activities under the project "Characterization and Quantification of global methane emissions by utilizing GOSAT and other satellite sensors" sponsored by Ministry of Environment Japan.
Professor Hayashida contributed to the Improved Limb Atmospheric Spectrometer (ILAS) Science Team as a leader of validation for aerosol extinction measurements. She has also worked on Stratospheric Aerosol and Gas Experiment (SAGE) II and other satellite sensors. She investigated the composition of Polar Stratospheric Clouds (PSCs) and their effects on chemical processes related to polar ozone destruction, by utilizing ILAS data. Her group also developed a new simple scheme to construct synoptic maps of chemical species by combining trajectory mapping with a photochemical box model (Chemical Species Mapping on Trajectories). She received Horiuchi Award from Japan Meteorological Society in 2002 for her scientific achievements. Later she extended her study to tropospheric ozone, focusing on the spatiotemporal variation of tropospheric ozone distribution.
She was a member of SPARC SSG from 2005 through 2008, and contributed to the joint scientific meeting of SPARC/IGAC in Kyoto, 2009 as one of the organizing committee members. Now, her most recent interest is methane emission from agriculture.