Validation of Atmospheric Infrared Sounder temperature and water vapor retrievals with matched radiosonde measurements and forecasts

Abstract

[1] An evaluation of the temperature and moisture profile retrievals from the Atmospheric Infrared Sounder (AIRS) data is performed using more than 2 years of collocated data sets. The Aqua-AIRS retrievals, global radiosonde (RAOB) measurements, forecast data from the National Center for Environmental Prediction Global Forecasting System (NCEP_GFS), the European Center for Medium Range Forecast (ECMWF), and the operational retrievals from the NOAA 16 satellite Advanced TIROS Operational Vertical Sounder (ATOVS) instrument are used in this validation. Using RAOB observations as the reference, bias and RMS differences are computed for ''sea,'' ''land,'' and ''all'' categories for the AIRS retrievals and other collocated data sets. The results of the intercomparison reveal that temperature and water vapor retrievals from the AIRS are in very good agreement with the RAOBs. The RMS difference for clear-only cases over ''sea'' and ''all'' categories is close to the expected goal accuracies, namely, 1°K in 1 km layers for the temperature and better than 15% in 2-km layers for the water vapor in the troposphere. The overall RMS difference for the cloud-cleared cases is also close to the expected product goal accuracy except for a slight degradation at the surface. When AIRS and ATOVS retrievals are compared with the RAOBs, the AIRS temperature retrievals show an improvement over ATOVS of at least 0.5°K for all the accepted cases. Both the ECMWF and the NCEP_GFS forecasts match the RAOB temperatures within 1°K and water vapor within 14%. With respect to biases, the AIRS final retrieval shows a larger bias with the RAOBs relative to ATOVS, NCEP_GFS, and ECMWF. The bias is highly influenced by a larger bias contribution from ''land'' samples and shows a month-to-month and annual variation that correlates with the CO 2 variations. This coupling suggests a need to include CO 2 and possibly other trace gas climatologies in the AIRS initial guess to partially mitigate the effects in the final physical retrieval.

A 6-year global cloud climatology from the Atmospheric InfraRed Sounder AIRS and a statistical analysis in synergy with CALIPSO and CloudSat

“…These atmospheric profiles were retrieved from cloud-cleared AIRS radiances within each AMSU footprint. Validations with radiosonde data from the NOAA-NESDIS operational meteorological database archive (Divakarla et al, 2006) and with Atmospheric Radiation Measurement (ARM) data (Tobin et al, 2006) have shown that the accuracy is close to 1 K in 1 km layers for temperature and better than 15% in 2 km layers for water vapour. For the cloud property retrieval we have collocated the AIRS L2 standard products (version 5) with a subset of AIRS L1B radiance measurements which have been downloaded from the NASA data pool (http://mirador.gsfc.nasa.gov).…”

Intercomparison of AIRS and HIRDLS stratospheric gravity wave observations

“…The clearest field of view in the 3 × 3 block is selected, and a single cloud-cleared infrared spectrum for the block is computed (Cho and Staelin, 2006). Validation of AIRS operational retrievals for the troposphere provide an accuracy which is near the anticipated absolute accuracy of 1 K root mean square over a 1 km layer Divakarla et al, 2006;. A root mean square deviation of 1.2 and 1.7 K is found in the troposphere and lower stratosphere, respectively, by comparing AIRS with radiosondes .…”

A microwave satellite water vapour column retrieval for polar winter conditions

“…Reanalysis data sets include the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim product (Dee et al, 2011), the National Centers for Environmental Prediction (NCEP; Kalnay et al, 1996) product, the Arctic System Reanalysis (ASR; Bromwich et al, 2010), and the Japanese 55 year Reanalysis (JRA-55; Kobayashi et al, 2015). Satellite products included were the Atmospheric Infrared Sounder (AIRS) Divakarla et al, 2006), Microwave Integrated Retrieval System (MIRS) (Boukabara et al, 2010), MH08 retrieval, and PLDC16 retrieval. AIRS satellite data included three different products: infrared measurements, microwave measurements (using AMSU-A), and combined (infrared and microwave) measurements.…”