Atmospheric Temperature and Absolute Humidity Profiles over the Beaufort Sea and Amundsen Gulf from a Microwave Radiometer

Abstract

Radiometrics MP-3000A microwave radiometric profiler (MWRP) provided high temporal resolution atmospheric profiles for temperature and absolute humidity up to 10 km, while 113 radiosondes were launched (and 68 were used in the analysis) over sea ice and the open ocean during the 2008 Circumpolar Flaw Lead System Study and the 2009 ArcticNet Cruise in the western Canadian High Arctic. The profiles were categorized by season and by the underlying sea ice concentrations. The MWRP was validated against the radiosonde data, focusing on the lower 2 km, which are generally influenced by the nature of the underlying surface. Root-mean-square (RMS) differences for temperature averaged 1.79 K through the lowest 2 km for the winter season, 1.81 K for spring, 2.51 K for summer, and 2.47 K for fall. Average biases of +0.99, +1.19, +2.13, and +2.08 K, respectively, indicate that the MWRP measurements were colder than the raobs for the lower 2 km. The RMS difference for absolute humidity averaged 0.25 g m?3 in the lowest 2 km during the winter season, 0.32 g m?3 for spring, 0.74 g m?3 for summer, and 0.37 g m?3 for fall. Average biases of +0.08 g m?3 for profiles over and sea ice concentration, +0.26 g m?3 for profiles over concentrations, and +0.16 g m?3 over and concentrations indicated that the MWRP measurements were slightly drier than the raobs for the lower 2 km. An estimate of the vertical resolutions indicated that it was as coarse as the height measured; however, the structure apparent in the profiles and the verification statistics suggest a higher vertical resolution, at least in the lowest 2 km.