Tomographic retrieval of cloud liquid water fields from a single scanning microwave radiometer aboard a moving platform – Part 1: Field trial results from the Wakasa Bay experiment

摘要

Tomographic methods offer great potential for retrieving three-dimensionalspatial distributions of cloud liquid water from radiometric observations bypassive microwave sensors. Fixed tomographic systems require multipleradiometers, while mobile systems can use just a single radiometer. Part 1(this paper) examines the results from a limited cloud tomography trial witha single-radiometer airborne system carried out as part of the 2003 AMSR-Evalidation campaign over Wakasa Bay of the Sea of Japan. During this trial,the Polarimetric Scanning Radiometer (PSR) and Microwave Imaging Radiometer(MIR) aboard the NASA P-3 research aircraft provided a useful dataset fortesting the cloud tomography method over a system of low-level clouds. We dotomographic retrievals with a constrained inversion algorithm using threeconfigurations: PSR, MIR, and combined PSR and MIR data. The liquid waterpaths from the PSR retrieval are consistent with those from the MIRretrieval. The retrieved cloud field based on the combined data appears to bephysically plausible and consistent with the cloud image obtained by a cloudradar. We find that some vertically-uniform clouds appear at high altitudesin the retrieved field where the radar shows clear sky. This is likely due tothe sub-optimal data collection strategy. This sets the stage for Part 2 ofthis study that aims to define optimal data collection strategies usingobservation system simulation experiments.