DUST IS A MAJOR TYPE OF AEROSOLS IN THE ATMOSPHERE AND A KEY COMPONENT OF THE EARTH SYSTEM. DUST CAN INTERACT WITH THE SOLAR AND TERRESTRIAL RADIATION CLOUD MICROPHYSICS AND HYDROLOGICAL CYCLES DECREASE THE SURFACE ALBEDO WHEN DEPOSITED ONTO SNOW/ICE PROVIDE NUTRIENTS FOR THE TERRESTRIAL AND OCEANIC BIOGEOCHEMISTRY AND IMPACT ATMOSPHERIC CHEMISTRY. THE SIMULATION OF DUST AEROSOL IN GLOBAL CLIMATE MODELS (GCMS) IS HOWEVER NOT WELL CONSTRAINED AND THE MODELED EMISSION AND BURDEN ARE ASSOCIATED WITH LARGE UNCERTAINTIES. THIS PROPOSAL AIMS AT IMPROVING THE DUST AEROSOL MODELING CAPABILITIES IN GCMS AND REDUCING THE UNCERTAINTY OF DUST AEROSOL RADIATIVE FORCING ON CLIMATE BY TAKING ADVANTAGE OF THE CLOUD-AEROSOL LIDAR AND INFRARED PATHFINDER SATELLITE OBSERVATION (CALIPSO) CLOUDSAT AND OTHER ATRAIN SATELLITE MEASUREMENTS. THE FIRST OBJECTIVE OF THIS PROPOSAL IS TO DEVELOP A NEW CLIMATOLOGICAL (~10 YEARS) DATASET OF 3-DIMENSIONAL (3-D) DUST AEROSOL DISTRIBUTIONS WITH AN IMPROVED DETECTION OF OPTICALLY THIN DUST LAYERS WHICH IS CRITICAL FOR STUDYING DUST-CLOUD INTERACTIONS. THE SECOND OBJECTIVE OF THE PROPOSAL IS TO USE THE NEW 3-D DATASET TO EVALUATE THE SPATIAL DISTRIBUTION SEASONAL CYCLE AND INTERANNUAL VARIABILITY OF DUST AEROSOL SIMULATED BY THE NCAR COMMUNITY EARTH SYSTEM MODEL/COMMUNITY ATMOSPHERE MODEL VERSION 5 (CESM-CAM5) AND THE NASA GODDARD EARTH OBSERVING SYSTEM MODEL VERSION 5 (GEOS-5). MODEL PERFORMANCE WILL BE ASSESSED AND WEAKNESSES BE IDENTIFIED. AS A THIRD OBJECTIVE WE WILL MAKE IMPROVEMENTS TO THE DUST AEROSOL REPRESENTATION IN CESM-CAM5 AND GEOS-5 WITH THE INCLUSION OF SUBGRID SURFACE WIND VARIABILITY FOR DUST EMISSION AND IMPROVE THE TREATMENT OF TRANSPORT AND SCAVENGING OF AEROSOLS IN CONVECTIVE CLOUDS. FINALLY THE CESM-CAM5 AND GEOS-5 MODELS WITH UPDATED DUST AEROSOL CAPABILITIES WILL BE USED TO STUDY DUST AEROSOL DIRECT AND INDIRECT EFFECTS ON CLIMATE. THIS PROPOSAL WILL PROVIDE AN IMPROVED TOOL FOR FUTURE STUDIES OF THE AEROSOL-EARTH SYSTEM INTERACTIONS AND FEEDBACKS ASSOCIATED WITH DUST AEROSOL. THE NEW DUST REPRESENTATION WILL BE USED IN THE GEOS-5 MODELING AND DATA ASSIMILATION SYSTEM TO PRODUCE AEROSOL RE-ANALYSIS FOR THE NASA S NUMERICAL WEATHER FORECAST AND AIR QUALITY STUDIES. THIS PROPOSAL DIRECTLY SUPPORTS SEVERAL OF THE NASA S CLOUDSAT AND CALIPSO RESEARCH THEMES. SPECIFICALLY IT PROVIDES PHENOMENOLOGICAL STUDIES OF FUNDAMENTAL AEROSOL PROCESSES AND EVOLUTION AS WELL AS AEROSOL INDIRECT EFFECTS AND VERTICAL TRANSPORT THIS PROPOSAL UTILIZES OBSERVATIONS THAT ARE AIMED AT DEVELOPMENT AND VALIDATION OF AEROSOL PARAMETERIZATIONS FOR REGIONAL GLOBAL AND CLIMATE MODELS IT DEVELOPS A NEW DATASET OF THE 3-D AEROSOL CLIMATOLOGIES SPATIAL CORRELATIONS AND TRENDS WITH USE OF CALIPSO AND CLOUDSAT PRODUCTS.