2013 年 33 巻 2 号 p. 137-149
During the 3.5-years of operation of the Greenhouse gases Observing SATellite (GOSAT), the GOSAT Data Handling Facility (DHF) of National Institute for Environmental Studies (NIES) has been producing many of the standard data products from the observation data of the two sensors, the Thermal And Near-infrared Sensor for carbon Observation (TANSO) - Cloud and Aerosol Imager (CAI) and the TANSO - Fourier Transform Spectrometer (TANSO-FTS). The standard data products, CAI Level 1B/1B+, FTS Short Wavelength Infra Red (SWIR) Level 2 (column amounts of CO2 and CH4, including column-averaged dry air mole fraction, XCO2 and XCH4), FTS Thermal Infra Red (TIR) Level 2 (profiles of CO2 and CH4 concentrations), CAI Level 2 (cloud flag), FTS Level 3 (global map of XCO2 and XCH4), and CAI Level 3 (global radiance and global reflectance), have been provided to General Users (GU). In addition, CAI Level 3 Normalized Difference Vegetation Index (NDVI) and Level 4A (CO2 flux) and Level 4B (global 3-dimensional CO2 concentration) have been released to GU since late 2012.
Since the FTS SWIR Level 2 data have been accumulated more than three years, seasonal variation and annual trends of XCO2 and XCH4 are shown for more than three years. In 2012, the versions up of FTS Level 1B, CAI Level 1B, CAI Level 2 cloud flag, and FTS SWIR Level 2 were done, and the data quality of the new version has been significantly improved for each of them. By using the new version of the FTS SWIR Level 2 product, the higher level products (Level 4A and Level 4B products) have been produced and released.