Dr. Wielicki's research has focused on clouds and their role in the Earth's radiative energy balance for over 30 years. He currently is the science team lead for the CLARREO (Climate Absolute Radiance and Refractivity Observatory) mission designed to serve as an in-orbit calibration reference to help reflected solar instruments increase accuracy by a factor of 5 to 10 and infrared instruments by a factor of 3 to 5. The primary goal is to reduce uncertainty about decadal climate change. Dr. Wielicki also served as Principal-Investigator on the CERES Investigation through 2008 and as a Co-Investigator on the NASA Cloudsat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) missions. Cloudsat and CALIPSO are centered on cloud studies and will fly in formation with the CERES instrument and other instruments on the Aqua platform.
In the 1980s, Dr. Wielicki was a Co-investigator on the Earth Radiation Budget Experiment and developed a new Maximum Likelihood Estimation (MLE) method for determination of the cloud condition in each ERBE field of view. This method enabled the development of the first estimates of cloud radiative forcing (CRF) by distinguishing individual observations as clear, partly-cloudy, mostly-cloudy, or overcast. This measurement became a standard of comparison for global climate models. The poor ability of global climate models to reproduce the ERBE cloud radiative forcing measurements was a key element in the designation of the "role of clouds and radiation" as the highest priority of the U.S. Global Change Research Program.
Dr. Wielicki was also a Principal Investigator on the First International Satellite Cloud Climatology Experiment (ISCCP) Regional Experiment (FIRE) and served as FIRE Project Scientist from 1987 to 1994. His research used Landsat satellite data to provide the first definitive validation of the accuracy of satellite derived cloud fractional coverage. More recently, he has demonstrated the surprising non-gaussian distributions of cloud optical depth present in broken boundary layer cloud fields, and has shown the large bias these distributions can cause in global climate model estimates of both solar and thermal infrared fluxes.
Throughout his career, Dr. Wielicki has pursued extensive theoretical radiative transfer studies of the effects of non-planar cloud geometry on the calculation of radiative fluxes, as well as on the retrieval of cloud properties and top of atmosphere radiative fluxes from space-based observations. Dr. Wielicki received his B.S. degree in Applied Math and Engineering Physics from the University of Wisconsin - Madison in 1974 and his Ph.D. degree in Physical Oceanography from Scripps Institution of Oceanography in 1980.