WE WILL USE CYGNSS WIND SPEED AND DERIVED SURFACE FLUX FIELDS THE COMPLEMENTARY IMERG PRECIPITATION DATASET AND CLOUD SYSTEM RESOLVING SIMULATIONS TO UNDERSTAND THE ROLE OF WIND-INDUCED FLUX VARIABILITY IN THE DESTABILIZATION AND PROPAGATION OF THE MADDEN-JULIAN OSCILLATION (MJO) AND BOREAL SUMMER INTRASEASONAL OSCILLATION (BSISO). THIS WORK EXTENDS THE BODY OF RESEARCH CONDUCTED BY THE PIS SUGGESTING AN IMPORTANT ROLE FOR WIND-INDUCED FLUXES IN DESTABILIZING THE MJO INCLUDING ON A PREDECESSOR NASA CYGNSS PROJECT. THE WORK WILL BE ORGANIZED BY THREE SPECIFIC HYPOTHESES: 1) WIND-INDUCED SURFACE FLUXES ARE IMPORTANT TO THE DESTABILIZATION OF THE MJO AND BSISO 2) WIND-INDUCED SURFACE FLUXES ARE IMPORTANT FOR SLOWING THE EASTWARD PROPAGATION OF THE MJO AND NORTHWARD PROPAGATION OF THE BSISO AND 3) COUPLING BETWEEN WIND-INDUCED SURFACE FLUXES AND CONVECTIVE SYSTEMS ON THE MESOSCALE CONTRIBUTES TO VARIATIONS IN CONVECTIVE ORGANIZATION DURING MJO/BSISO EVENTS. TO ADDRESS HYPOTHESES 1 AND 2 SURFACE HEAT FLUXES DERIVED FROM CYGNSS WIND SPEED OBSERVATIONS WILL BE USED TO DETERMINE THE MAGNITUDE AND PHASE RELATIONSHIP OF INTRASEASONAL FLUX ANOMALIES RELATIVE TO PRECIPITATION ASSESSING THEIR RELATIVE IMPORTANCE COMPARED TO OTHER TERMS IN THE MJO MOIST STATIC ENERGY AND MOISTURE BUDGETS INCLUDING RADIATIVE FEEDBACKS AND HORIZONTAL ADVECTION. WORK WILL ALSO BE CONDUCTED TO CHARACTERIZE VARIABILITY IN THE WIND SPEED DIURNAL CYCLE AND THE RESULTING MODULATION OF SURFACE FLUXES BETWEEN MJO SUPPRESSED AND ENHANCED PHASES QUANTIFYING THEIR CONTRIBUTIONS TO MJO PROPAGATION. MODEL SENSITIVITY TESTS USING SPECTRAL WEAK TEMPERATURE GRADIENT METHODS WITH A CLOUD SYSTEM RESOLVING MODEL (CSRM) IN WHICH INTRASEASONAL FLUX VARIABILITY FOR KEY MJO EVENTS IS REMOVED WILL CONFIRM THE IMPORTANCE OF SURFACE FLUX VARIABILITY TO MJO CONVECTION. LEVERAGING REGIONAL BSISO SIMULATIONS CONDUCTED AS PART OF THE ONR PISTON SCIENCE TEAM WE WILL EXTEND THESE SIMULATIONS TO EXAMINE THE SENSITIVITY OF BSISO DESTABILIZATION AND PROPAGATION TO REMOVING INTRASEASONAL SURFACE FLUXES AND OCEANIC AND LAND SURFACE DIURNAL CYCLE INFLUENCE ON THESE FLUXES. TO ADDRESS HYPOTHESIS 3 THE RELATIONSHIP BETWEEN MESOSCALE VARIABILITY IN WIND SPEED DERIVED FLUXES AND COMPLEMENTARY PRECIPITATION ESTIMATES ALONG CYGNSS SWATHS WILL BE STATISTICALLY EXAMINED TO ASSESS THE ROLE OF SURFACE FLUX FEEDBACKS IN SUPPORTING MESOSCALE ORGANIZATION DURING MJO EVENTS AND AS A MEANS TO VALIDATE CSRM REPRESENTATION OF THIS RELATIONSHIP. SENSITIVITY TESTS WITH A CSRM USING SPECTRAL WTG METHODS WILL THEN BE USED TO ASSESS THE IMPORTANCE OF MESOSCALE FLUX VARIABILITY TO CONVECTIVE ORGANIZATION AND MJO DESTABILIZATION BY SPATIALLY HOMOGENIZING TIME-VARYING SURFACE FLUXES IN THE MODEL. THIS WORK WILL HELP ASSESS THE IMPORTANCE OF LOCAL WIND VARIABILITY FOR SUPPORTING THE MCS BUILDING BLOCKS OF THE MJO.