A Miniaturized Water Vapor Profiling Radiometer for Network-based 3-D Measurements of the Tropospheric Water Vapor Field

Knowledge of the temporal and spatial distribution of water vapor and liquid water in the troposphere is fundamental for short- and medium-range prediction of precipitation and severe weather. Current measurements of these quantities in the troposphere are limited by optical extinction in clouds (lidar), in temporal resolution (radiosondes), in spatial resolution (GPS networks) and in spatial coverage (microwave radiometers). In order to facilitate three-dimensional (3-D) measurements of tropospheric water vapor with good temporal and spatial resolution, a new Miniaturized Water Vapor profiling Radiometer (MWVR) has been developed at Colorado State University and the University of Massachusetts Amherst. This new radiometer takes advantage of recent advances in Monolithic Microwave and Millimeter-wave Integrated Circuit (MMIC) technology to reduce substantially the mass, volume, power consumption and cost of passive microwave instruments. A second MMIC-based radiometer is under development to distinguish cloud liquid water from water vapor. A network of scanning MWVRs is planned to demonstrate 3-D measurements of both water vapor and cloud liquid water in near-real time. Microwave radiometers deployed on ground-based and airborne platforms perform extensive measurements to calibrate and validate satellite sensors such as the DMSP SSM/I, NASA’s TMI on TRMM, Navy/NPOESS WindSat, NOAA’s AMSU-A and AMSU-B, and NASA’s AMSR-E on Aqua. In addition, microwave radiometers are used for fundamental investigations to study the relationship of physical properties of the scene, i.e. land, atmosphere and oceans, to the brightness temperature