THE MADDEN-JULIAN OSCILLATION (MJO) REMAINS A MAJOR CHALLENGE FOR BOTH GLOBAL AND REGIONAL MODELS DUE TO OUR INCOMPLETE UNDERSTANDING OF IT. NASA'S CYCLONE GLOBAL NAVIGATION SATELLITE SYSTEM (CYGNSS) MISSION WILL PROVIDE A VITAL PIECE OF INFORMATION IN MJO DYNAMICS: NEAR SURFACE WINDS UNDER ALL WEATHER CONDITIONS WITH A HIGH TEMPORAL AND SPATIAL RESOLUTION. THE WORK PROPOSED HEREIN WILL INVESTIGATE THE IMPACT OF CYGNSS DATA ON SIMULATING THE STRUCTURE AND PROPAGATION OF MJO USING BOTH A REGIONAL MODEL AND A CLOUD-RESOLVING MODEL. SINCE CYGNSS WILL NOT BE LAUNCHED UNTIL 2016 WE WILL TAKE ADVANTAGE OF THE HIGH-QUALITY DATASET FROM THE RECENTLY FINISHED DYNAMICS OF THE MADDEN-JULIAN OSCILLATION (DYNAMO OCTOBER 1 2011 ~ FEBRUARY 8 2012) FIELD CAMPAIGN.THE PROPOSED REGIONAL MODEL FOR THIS STUDY IS THE COUPLED-OCEAN-ATMOSPHERE-WAVE-SEDIMENT TRANSPORT (COAWST) MODELING SYSTEM. THIS SYSTEM COUPLES THE WEATHER RESEARCH AND FORECASTING (WRF; ATMOSPHERE) MODEL THE SIMULATING WAVES NEARSHORE (SWAN; WAVE) MODEL AND THE REGIONAL OCEAN MODELING SYSTEM (ROMS; OCEAN) VIA THE MODEL COUPLING TOOLKIT (MCT). THE CLOUD RESOLVING MODEL IS THE GODDARD CUMULUS ENSEMBLE (GCE) MODEL. WE PLAN TO FOCUS ON THE TWO WELL-OBSERVED MJO EVENTS DURING DYNAMO CAMPAIGN PERIOD IN OCTOBER AND NOVEMBER 2011. THE FULLY COUPLED COAWST MODEL WILL BE USED TO SIMULATE THESE EVENTS AND THE SIMULATED STORM STRUCTURE SURFACE FLUXES SURFACE WIND AND WAVE HEIGHTS WILL BE COMPARED WITH OBSERVATIONS DURING THE DYNAMO CAMPAIGN. THE FORWARD MODEL DEVELOPED BY CYGNSS TEAM WILL BE APPLIED TO THE SWAN WAVE MODEL OUTPUT IN ORDER TO PRODUCE SYNTHETIC CYGNSS DATA FOR GENERAL PRE-LAUNCH STUDIES. IN THIS PROPOSED STUDY THIS DATASET WILL BE USED TO NUDGE THE NEAR SURFACE WINDS IN THE CLOUD-RESOLVING MODEL IN ORDER TO STUDY IMPACT OF CYGNSS DATA ON MODEL RESULTS. THE SURFACE WIND AND AIR-SEA INTERACTIONS PLAY CRUCIAL ROLES IN MJO DEVELOPMENT AND PROPAGATION. THE COAWST MODELING SYSTEM AND THE GCE CLOUD-RESOLVING MODEL EACH HAS ITS UNIQUE ABILITY TO ADDRESS SOME OF THE KEY QUESTIONS RELATED TO THESE TOPICS. FOREXAMPLE THE NESTED COAWST MODEL HAS A LARGE DOMAIN AND FULLY INTERACTIVE ATMOSPHERE OCEAN AND WAVE COMPONENTS. IT WILL BE USED TO STUDY HOW INCLUDING OCEAN/WAVE COMPONENT CAN AFFECT SIMULATED SURFACE FLUXES LOW-LEVEL CONVERGENCE AND WATER VAPOR BUDGET AND HOW THESE FACTORS INFLUENCE MJO STRUCTURES AND STRENGTHS. THE HIGH-RESOLUTION GCE MODEL WILL BE USED TO STUDY THE BUILDING BLOCKS OF ORGANIZED TROPICAL CONVECTION: THE INDIVIDUAL MESOSCALE CONVECTIVE SYSTEMS. THE EMPHASIS WILL BE ON DYNAMICS OF CONVECTION AND ITS ASSOCIATED DOWNDRAFT SURFACE OUTFLOW AND COLD POOL AS WELL AS THEIR INTERACTIONS WITH THE OCEAN SURFACE EVAPORATION AND WAVE DRAG. THE DYNAMO DATA WILL PROVIDE GOOD CONSTRAINTS ON THESE MODEL SENSITIVITY STUDIES. FURTHERMORE COAWST MODEL AND THE GCE MODEL SHARE THE SAME OCEAN SURFACE FLUX SCHEME. THIS SCHEME WILL BE IMPROVED USING DYNAMO CASES AND DATA. THE IMPROVED SURFACE FLUX SCHEME WILL BE IMPLEMENTED IN THE NASA UNIFIED WRF AND SENSITIVITY TESTS WILL BE CARRIED OUT. THIS POTENTIALLY CAN LEAD TO BETTER MJO REPRESENTATION IN THE WRF FORECAST MODEL.THIS PROPOSAL ADDRESSES NASA ROSES 2013 A.22 PROPOSAL CALL'S RESEARCH THEME ON "IMPROVE UNDERSTANDING OF THE EVOLUTION AND CHARACTERISTICS OF THE MJO" "INCREASE UNDERSTANDING OF THE PROCESSES THAT LEAD TO ORGANIZATION OF CONVECTION ON LARGE SCALES" AND "BETTER CHARACTERIZATION OF THE DYNAMICS OF DEEP CONVECTIVE COLD POOLS SURFACE GUSTINESS AND OCEAN SURFACE EVAPORATION" USING CYGNSS DATA PRODUCTS.