Validation of AIRS V6 Temperature Profiles and Surface-Based Inversions over Antarctica using Concordiasi Dropsonde Data

The 2010 Concordiasi field experiment took place over Antarctica from September to December, 2010. During Concordiasi, for the first time, thirteen NCAR Driftsonde systems were launched from McMurdo station, ascended to the stratosphere, and then drifted with the winds. The Driftsonde provides a unique platform to release dropsondes that measure the atmosphere from the lower stratosphere to the surface in otherwise difficult to reach parts of the globe. A total of 639 soundings were obtained and provided unprecedented high quality profiles over Antarctica, especially over Antarctic continent where upper air observations are scarce and satellite retrievals are challenging. This study uses temperature profiles and Surface-based inversion (SBI) properties derived from Concordiasi high-resolution dropsonde data to validate the Advanced InfraRed Sounder (AIRS) newest version (Version 6) data. Previous study (Wang et al. 2013) found that the satellite data including AIRS Version 5 can reproduce temperature profiles reasonably well, but have consistent cold biases with larger magnitudes over Land. AIRS V6 data are evaluated here. AIRS V6 averaging kernel is applied to the dropsonde data, which properly accounts for the vertical resolution of the AIRS algorithm and enables a more 'apples-to-apples' comparison between the sonde and AIRS retrievals. AIRS V6 is superior than V5 data in both systematic and random errors of temperature profiles, and land-ocean contrast in biases comparing to the dropsonde data. AIRS V6 can detect 78% of SBIs seen by the dropsonde data and agree with the dropsonde data on the SBI depths for most of cases. However, AIRS V6 systematically underestimates the SBI intensities as a result of its warmer surface temperature. The results are very encouraging for future usage of AIRS data to study Antarctic SBIs, which play an important role in Antarctic climate. Wang, J., T. Hock, S. A. Cohn, C. Martin, N. Potts, T. Reale, B. Sun and F. Tilley, 2013: Unprecedented upper air dropsonde observations over Antarctica from the 2010 Concordiasi Experiment: Validation of satellite-retrieved temperature profiles. Geophys. Res. Lett., 40, DOI: 10.1002/grl.50246.