This research will use CERES, MODIS and CALIPSO measurements synergistically to provide an observation-based assessment of the influence of aerosols and ice clouds on the Earth's radiation budget. CALIPSO will provide critical new information needed to improve current estimates of the clear-sky direct radiative effect (DRE) of aerosols. Current techniques based on passive instruments suffer from surprisingly large uncertainties due cloud clearing algorithms and a lack of aerosol height information. By using CERES, MODIS and CALIPSO measurements in a synergistic manner, uncertainties due to cloud-clearing errors will be reduced and improved aerosol DRE estimates over both ocean and land will be derived. Aerosol height information from CALIPSO, together with radiative fluxes from CERES, will be used to determine the LW direct radiative effect of aerosols, particularly in regions of desert dust. By merging CALIPSO and MATCH aerosol type information with radiative fluxes from CERES and MODIS, estimates of the aerosol DRE by aerosol type will be generated. CERES, MODIS and CALIPSO data will also be used to study the radiative effect of ice clouds. Current passive techniques have difficulty determining the height of thin ice clouds and often completely miss the cirrus altogether. CALIPSO will provide unprecedented information on cirrus that, combined with CERES and MODIS, will lead to a far better understanding of how ice clouds influence the Earth�s radiation budget. Results from this investigation will provide the modeling community with highly relevant global data to validate and improve climate models.
