Simultaneous measurements of atmospheric water vapor with MIR, Raman lidar and rawinsondes

Abstract

Simultaneous measurements of atmospheric water vapor were made by millimeter-wave imaging radiometry (MIR), Raman lidar and rawinsondes. Three types of rawinsonde sensor packages (AIR, Vaisala and VIZ) were carried by the same balloon. The measured water vapor profiles from Raman lidar and the Vaisala, VIZ and AIR sondes are used in the radiative transfer calculations. The resultant brightness temperatures are compared with those measured from the MIR at all six frequencies (89, 150, 183.3/spl plusmn/1, 183.3/spl plusmn/3, 183.3/spl plusmn/7, and 220 GHz). The results show that the MIR measured brightness temperatures agree well (within /spl plusmn/2 K) with those calculated from the Raman lidar and Vaisala measurements. The brightness temperatures calculated from the AIR sondes differ from the MIR measurements by as much as 10 K. The discrepancy and its implication are discussed in detail. >