The Satellite Atmospheric Sounder IKFS-2: 2. Validation of the Temperature Sounding of the Atmosphere

Resumo

The validation of measurements of vertical temperature profiles by the IKFS-2 instrument (the Meteor-M no. 2 satellite) in cloudless conditions was based on the comparison with radiosonde measurements and data from NCEP GFS analysis. Vertical resolution matching is shown to decrease the root-mean-square (RMS) difference between the results provided by the two measurement methods by 0.2–1 K depending on the altitude in the atmosphere. When the vertical resolution is matched the absolute values of the mean differences between the satellite and the radiosonde measurements do not exceed 1 K and the mean square differences vary from 1.2 to 1.8 K, except for the surface layer, where they reach 2 K and 4 K, respectively. The RMS differences between the satellite temperature measurements and NCEP GFS data show worse agreement over the ground (up to 2 K against 1.2–1.5 K for sounders). In the 300–600 hPa pressure interval, the RMS difference between satellite and NCEP GFS data is less than 1 K over water surface but increases to 1.5–2 K over land. In the cloudless cases, the accuracy of sounding over water surface by IKFS-2 (when compared with the analysis results) approaches the accuracy displayed by IASI, which is functionally similar to IKFS-2.