Remote Detection of Cloud Base Heights Using CloudSat and CALIPSO

摘要

This thesis study focuses on the evaluation of cloud base height from a pair of space-based remote sensing systems. The first satellite, CloudSat, is a 94-GHz cloud profiling radar (CPR) utilizing a wavelength capable of penetrating thick hydrometeor layers. The second satellite, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite, is an active lidar designed to detect optically thin hydrometeor layers. The 2BGEOPROF- Lidar product combines data from these two synergistic observing platforms to provide a complete profile of the vertical structure of clouds in the atmosphere. For this research, 2B-GEOPROF-Lidar cloud base height measurements were validated against cloud base height measurements from a combined suite of ground-based sensors at four Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) sites. Cloud base height measurements validated within 480 meters, the vertical resolution of the CPR, were deemed accurate assessments. Differences in cloud base height exceeding 720 meters were labeled as significant outliers. Significant outliers were further investigated to find trends in radar reflectivity and cloud mask data from CloudSat and total attenuated backscatter from CALIPSO. The combined CloudSat / CALIPSO cloud base assessment proved accurate in 73% of the cases studied.