Validation of ILAS-II version 1.4 O3, HNO3, and temperature data through comparison with ozonesonde, ground-based FTS, and lidar measurements in Alaska



[1] Version 1.4 data from the Improved Limb Atmospheric Spectrometer-II (ILAS-II) were validated through comparison with profile data measured by several instruments at Poker Flat (65.1°N, 147.5°W), Alaska. The height profiles of O3 and HNO3 provided by ILAS-II were compared with those retrieved from spectra measured by a ground-based Fourier transform infrared spectrometer (FTS). The O3 and HNO3 abundances measured by ILAS-II and FTS in the 17–35 km altitude range agreed within the precision of the two measurements. The O3 volume mixing ratios measured by ILAS-II above (below) 20 km were 10% lower (higher) than those from the FTS measurements. The HNO3 values from ILAS-II and FTS agreed to within 10% above 17 km. The O3 profiles obtained from electrochemical concentration cell (ECC) ozonesondes launched from Fairbanks (64.8°N, 147.9°W) were also compared to ILAS-II data. The ILAS-II ozone abundance agreed with the ozonesonde values. Comparison of mesospheric and upper stratospheric temperature data obtained by ILAS-II and Rayleigh lidar indicated that the temperature derived from ILAS-II was significantly higher (lower) than that from lidar at about 60 (40) km.