Retrieval of Atmospheric Water Vapor Density With Fine Spatial Resolution Using Three-Dimensional Tomographic Inversion of Microwave Brightness Temperatures Measured by a Network of Scanning Compact Radiometers

Quantitative precipitation forecasting is currently limited by the paucity of observations on sufficiently fine temporal and spatial scales. Three-dimensional water vapor fields can be retrieved with improved spatial coverage from measurements obtained using a network of scanning microwave radiometers. To investigate this potential, an observation system simulation experiment was performed in which synthetic examples of retrievals using a network of radiometers were compared with results from the Weather Research and Forecasting model at a grid scale of 500 m. These comparisons show that the 3-D water vapor field can be retrieved with an accuracy of better than 15%-20%. A ground-based demonstration network of three compact microwave radiometers was deployed at the Atmospheric Radiation Measurement Southern Great Plains site in Oklahoma. Results using these network measurements demonstrated the first retrieval of the 3-D water vapor field in the troposphere at fine spatial and temporal resolutions.