Update on Validation of GOSAT and GOSAT-2 FTS SWIR L2 Products

Abstract:

The Greenhouse gases Observing SATellite (GOSAT), launched on 23 Jan. 2009, is the world's first satellite dedicated to measuring the concentrations of the two major anthropogenic greenhouse gases, carbon dioxide (CO₂) and methane (CH₄), from space. Column-averaged dry air mole fractions of CO₂, CH₄, and water vapor (H₂O) (denoted as XCO₂, XCH₄ and XH₂O) are retrieved from the Short-Wavelength InfraRed (SWIR) spectral data observed with the Thermal And Near-infrared Sensor for carbon Observation - Fourier Transform Spectrometer (TANSO-FTS) onboard GOSAT. The present NIES full physics SWIR retrieval algorithm (Ver. 02.90) for land high-gain soundings showed small biases and standard deviations, by comparing with data of the Total Carbon Column Observing Network (TCCON) (version GGG2014): -0.35 ppm and 2.19 ppm for XCO₂, -2.2 ppb and 13.4 ppb for XCH₄, and -0.8% and 32.3% for XH₂O, respectively. Retrievals from the GOSAT TANSO-FTS SWIR spectra are already being used for scientific research applications for 11 years.

GOSAT-2, a successor of GOSAT, was launched on 29 Oct. 2018, and is now in operation. In addition to XCO₂, XCH₄, and XH₂O, XCO (column-averaged dry air mole fraction of carbon monoxide) is retrieved from GOSAT-2 TANSO-FTS-2 SWIR spectra. The FTS-2 SWIR L2 products retrieved by the full physics and proxy algorithms have been released to researchers belonging to the GOSAT series Research Announcement.

In this presentation, we focus on current status of the GOSAT and GOSAT-2 products and validation for the GOSAT and GOSAT-2 FTS-2 SWIR L2 products using the TCCON data, as well as related validation activities.