THIS PROPOSAL ADDRESSES THE NASA DATA FOR OPERATION AND ASSESSMENT CALL A.29 JOINT CENTER FOR SATELLITE DATA ASSIMILATION. THE OBJECTIVE OF THIS PROPOSAL IS TO IMPROVE THE ASSIMILATION OF AEROSOL-AFFECTED RADIANCES INTO NUMERICAL WEATHER PREDICTION (NWP) MODELS WITHIN THE GRIDPOINT STATISTICAL INTERPOLATION (GSI) SYSTEM. THIS PROPOSAL OBJECTIVE WILL BE ACCOMPLISHED BY PROVIDING COMPREHENSIVE NEAR GLOBAL AEROSOL INFORMATION FROM OUR NASA SHORT-TERM PREDICTION RESEARCH AND TRANSITION CENTER (SPORT) AEROSOL OPTICAL DEPTH (AOD) COMPOSITE PRODUCT INTO THE COMMUNITY RADIATIVE TRANSFER MODEL (CRTM) IN AN EFFORT TO SIMULATE ACCURATE AEROSOL-AFFECTED RADIANCES FOR ASSIMILATION INTO NWP MODELS. PREVIOUS RESEARCH HAS CONCLUSIVE EVIDENCE THAT COARSE MODE DUST PARTICLES POSSESS STRONG SCATTERING AND ABSORBING PROPERTIES AT INFRARED WAVELENGTHS WHICH AFFIRMS THE IMPORTANCE OF ACCOUNTING FOR THESE PARTICLES WHEN SIMULATING INFRARED RADIANCES. HOWEVER THEIR IMPACT ON SIMULATED INFRARED RADIANCES IS CURRENTLY IGNORED WHICH CAN LEAD TO THE ASSIMILATION OF UNREPRESENTATIVE INFRARED RADIANCES INTO NUMERICAL MODELS AND SUBSEQUENT ERRORS IN THE MODEL ANALYSIS AND FORECAST. THIS PROPOSED RESEARCH AIMS TO ADVANCE IMPROVEMENTS WITH CURRENT OPERATIONAL DATA ASSIMILATION SYSTEMS BY IMPLEMENTING THE FRAMEWORK FOR THE ASSIMILATION OF AEROSOL-AFFECTED RADIANCES INTO THESE SYSTEMS BY COMPLETING THE FOLLOWING KEY OBJECTIVES: 1) DIAGNOSE THE ABILITY OF THE CURRENTLY ADOPTED AEROSOL MODULES IN THE CRTM IN SIMULATING THE SATELLITE INFRARED RADIANCE IN THE PRESENCE OF COARSE DUST PARTICLES. 2) QUANTIFY THE OVERALL IMPACT OF DUST AEROSOLS ON THE SIMULATED INFRARED RADIANCES FROM THE CRTM AND DETERMINE WHETHER ADDITIONAL AEROSOL INFORMATION INTO THE CRTM LEADS TO A REDUCTION IN RADIATIVE TRANSFER MODEL ERROR. 3) DIAGNOSE WHETHER THE ASSIMILATION OF AEROSOL-AFFECTED RADIANCES LEADS TO A REDUCTION IN ERRORS IN THE MODEL ANALYSIS AND FORECAST FIELDS (E.G. TEMPERATURE AND WATER VAPOR). TO SUCCESSFULLY COMPLETE THESE KEY OBJECTIVES WE WILL VALIDATE THE CRTM AEROSOL MODULE BY SIMULATING DUST AEROSOLAFFECTED RADIANCES FOR INTENSIVE CASE STUDIES WHERE THE RETRIEVALS OF AEROSOL PROPERTY PROFILES FROM THE ACTIVE SENSORS ONBOARD THE CLOUD- AEROSOL LIDAR AND INFRARED PATHFINDER SATELLITE OBSERVATIONS (CALIPSO) AND CLOUD-AEROSOL TRANSPORT SYSTEM (CATS) WILL BE USED AS INPUT INTO THE CRTM. AFTER VALIDATING THE CRTM AEROSOL MODULE WE WILL CONDUCT THREE EXPERIMENTAL SIMULATIONS FOR EACH DUST CASE CONSISTING OF A CONTROL RUN (CTRL) THAT NEGLECTS THE PRESENCE OF AEROSOLS AND TWO EXPERIMENTAL RUNS WHERE AEROSOL INFORMATION IS INPUT INTO THE CRTM. THE FIRST EXPERIMENTAL RUN (EXP-GEOS) USES 3-D AEROSOL MASS CONCENTRATIONS FROM THE GLOBAL GODDARD EARTH OBSERVING SYSTEM MODEL VERSION 5 (GEOS-5) AS INPUT INTO THE CRTM WHILE THE SECOND EXPERIMENTAL RUN (EXP-SPORT) USES 3- D CONCENTRATIONS CALCULATED FROM OUR SPORT AOD COMPOSITE PRODUCT. THE SIMULATED INFRARED RADIANCES FROM EACH EXPERIMENT WILL BE THOROUGHLY DIAGNOSED AGAINST OBSERVATIONS FROM PASSIVE SATELLITE SENSORS TO VERIFY WHETHER THE ADDITIONAL AEROSOL INFORMATION CAN LEAD TO A REDUCTION IN FORWARD MODEL ERROR. WE WILL THEN USE THE CURRENT OPERATIONAL GEOS-5/GSI FRAMEWORK TO ASSIMILATE THE INFRARED RADIANCES AND CONDUCT 24-HOUR FORECASTS FOR EACH EXPERIMENT. THE MODEL ANALYSIS AND FORECAST FIELDS PARTICULARLY THE TEMPERATURE WATER VAPOR AND WIND FIELDS WILL BE EXTENSIVELY VERIFIED AGAINST RADIOSONDE MEASUREMENTS. WE HYPOTHESIZE THAT THE USE OF ADDITIONAL AEROSOL INFORMATION IN CRTM WILL REDUCE FORWARD MODELING ERROR FOR INFRARED RADIANCES AND SUBSEQUENTLY REDUCE BIASES IN THE TEMPERATURE AND MOISTURE ANALYSIS FIELDS OF THE MODEL ULTIMATELY LEADING TO AN INCREASE IN FORECAST SKILL. OVERALL THIS WORK WILL DETERMINE THE FRUITFULNESS OF ASSIMILATING AEROSOL-AFFECTED INFRARED RADIANCES IN OPERATIONAL MODELS AND PAVE THE WAY FOR FUTURE ADVANCES IN DATA ASSIMILATION METHODOLOGIES.