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

Abstract

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.