Atmospheric Temperature and Water Vapor Retrievals from GOSAT Thermal Infrared Spectra and Initial Validation with Coincident Radiosonde Measurements

摘要

References(27) Cited-By(1) Supplementary materials(1) Atmospheric temperature and water vapor profiles are retrieved from thermal infrared spectral radiances measured with the Thermal And Near infrared Sensor for carbon Observation-Fourier Transform Spectrometer (TANSO-FTS). An initial validation of these retrievals was carried out with dedicated radiosonde measurements over the land and the ocean. Comparisons are made between measurements that are matched closely in both time (one hour) and space (110 km). The differences in individual matchups for water vapor and temperature are within 50% and 3 K, respectively, in most regions of the vertical profile. For the water vapor retrieval, the mean difference from radiosonde data is less than 20%, and the standard deviation of the difference is smaller than 25% for both land and ocean scenes. For the temperature retrieval, the comparison with the radiosonde profiles indicates that the mean difference is better than 1.5 K with 1.2 K standard deviation. We find that uncertainty in surface emissivity could make water vapor and temperature retrievals in the lower troposphere difficult. We also demonstrate a negative correlation between the water vapor in the atmospheric column and the precision of the retrievals.