Validation of the version 5 Goddard Earth Observing System (GEOS-5) using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)

This dissertation compares the Planetary Boundary Layer (PBL) height produced by the Goddard Earth Observing System-version 5 (GEOS-5) model with Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Part of GEOS-5 is an Atmosphere Global Circulation Model (GCM). Developers are uncertain of the precision of model PBL height predictions (i.e. climatology), since there are limited direct observations of the PBL height. Validation of the PBL height serves as a diagnostic on whether the physics and dynamics packages are correct in the model. Thus, verification is needed. For the first time ever, PBL heights have been derived from CALIPSO using a new hybrid standard deviation algorithm, which in some cases is more sensitive than traditional approaches (i.e. Haar wavelet method). Observations made at the UMBC Elastic Lidar Facility (ELF) have been used to determine the validity of the satellite-derived PBL estimate. This is the first global observational study of PBL heights using CALIPSO with match-ups to the GEOS-5 MERRA model. Extensive comparisons between the model output and satellite observations in the western Hemisphere and over Africa gave model-measurement correlation coefficients between 0.47 - 0.73. Comparisons have been performed for regions over land and water using clouds, aerosols and mixed cloud-aerosol features to detect the PBL. The present study provides insight of PBL height variances in the GEOS-5 model. A case over the Equatorial Pacific indicates that PBL heights from the GEOS-5 model are greater than 25%, on average, than the satellite-derived PBL parameter. PBL height biases in the Equatorial Pacific may be related to the General Circulation Model (GCM) coupling scheme implemented in GEOS-5.