Validation of Atmospheric Infrared Sounder (AIRS) temperature, water vapor, and ozone retrievals with matched radiosonde and ozonesonde measurements and forecasts

An evaluation of the temperature, water vapor, and ozone profile retrievals from the AIRS data is performed with more than three years of collocated radiosondes (RAOBs) and ozonesonde (O 3 SND) measurements. The Aqua-AIRS version 4.0 retrievals, global RAOB and O 3 SND measurements, forecast data from the NCEP_GFS, ECMWF, and the NOAA- 16 ATOVS retrievals are used in this validation and relative performance assessment. The results of the inter-comparison of AIRS temperature, water vapor and ozone retrievals reveal very good agreement with the measurements from RAOBs and O 3 SND s. The temperature RMS difference is close to the expected product goal accuracies, viz. 1 o K in 1 km layers for the temperature and close to 15% in 2-km layers for the water vapor in the troposphere. The AIRS temperature retrieval bias is a little larger than the biases shown by the ATOVS, NCEP_GFS, and ECMWF forecasts. With respect to the ozone profile retrieval, the retrieval bias and RMS difference with O 3 SNDs is less than 5% and 20% respectively for the stratosphere. The total ozone from the AIRS retrievals matches very well with the Dobson/Brewer station measurements with a bias less than 2%. Overall, the analysis performed in this paper show a remarkable degree of confidence in the AIRS retrievals.