Lidar for calibration/validation of microwave sounding instruments

摘要

Several lidar campaigns have been performed in support of calibration/validation of DMSP SSM/T-2 microwave water vapor sensors. Calibration capabilities were demonstrated by performing radiative transfer calculations based on water vapor profiles measured by lidar. The calculations agreed with collocated SSM/T-2 atmospheric channel measurements to better than 1K RMS, whereas discrepancies were frequently greater than 2 K for radiative transfer based on conventional AIR and Vaisala radiosonde profiles. The improved capability is attributed to the new ability to measure water vapor from 8 to 14 km altitude. Conventional radiosondes tend to be unresponsive to water vapor at the low temperatures typical of altitudes above 8 km.