Article ID: 2024.012
The Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW) will be launched in the Japanese fiscal year 2024. The Total Anthropogenic and Natural emissions mapping SpectrOmeter-3 (TANSO-3), one of the instruments onboard GOSAT-GW, is an imaging grating spectrometer that measures backscattered sunlight, from which the column-averaged dry-air mole fractions of carbon dioxide (XCO2) and methane (XCH4) and the total and tropospheric vertical column densities (VCDs) of nitrogen dioxide (NO2) will be derived (TANSO-3 Level 2 products). TANSO-3 will have two observation modes: Wide Mode, with a ~900 km swath width and a ~10 km footprint size; and Focus Mode, with ~90 km × 90 km observation areas and a < 3 km footprint size. The TANSO-3 Level 2 products will be validated primarily with data from global ground-based remote sensing networks. Total Carbon Column Observing Network (TCCON) and COllaborative Carbon Column Observing Network (COCCON) data will be used to validate XCO2 and XCH4, while Pandonia Global Network (PGN) and Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) data will be used for NO2 VCD. Airborne in situ measurements, satellite measurements other than GOSAT-GW, and simulated concentration fields from atmospheric transport models will complement the ground-based data. In order to validate the Focus Mode data in urban areas, it is crucial to evaluate small-scale spatial gradients in XCO2, XCH4, and NO2 VCD. Therefore, we are developing an urban operational observation network in the Tokyo metropolitan area, Japan, by deploying co-located EM27/SUN (COCCON instruments) and Pandora (PGN instruments) spectrometers.
