Comparison of near-infrared and thermal infrared cloud phase detections

[1] We compare the results of the cloud thermodynamic phase detections that use (1) the ratio of the near-infrared and visible bands or (2) the brightness temperature difference of two thermal infrared bands. We find that the brightness temperature difference algorithm using the Moderate Resolution Imaging Spectroradiometer (MODIS) bands is generally consistent with the expectations based on the retrieval of the cloud top radiative temperature. On the other hand, the band ratio method, which uses near-infrared and visible bands, assigns considerably more ice phase compared to the brightness temperature difference method and leads to discrepancies with the expectations based on the cloud top radiative temperature. When the cloud phase algorithm, developed originally for the Department of Energy Multispectral Thermal Imager research satellite, is applied to the MODIS imagery, the cloud phase assignments are close to the brightness temperature difference results and are in better agreement with the expectations based on the cloud top radiative temperature.