MAJOR OCEAN CURRENTS AND UPWELLING ZONES ARE ACCOMPANIED BY SHARP SEA SURFACE TEMPERATURE (SST) FRONTS. HYDRODYNAMIC INSTABILITIES CAUSE THE FRONTS TO MEANDER AND SHED EDDIES WHILE OCEAN EDDIES FEED BACK ONTO THE MEAN FLOW THROUGH FLUXES OF MOMENTUM HEAT AND POTENTIAL VORTICITY. WITH HIGH RESOLUTION AND FREQUENT SAMPLING SATELLITE SCATTEROMETER OBSERVATIONS OVER THE PAST TWO DECADES REVEALED MARKED MESOSCALE OCEAN-ATMOSPHERE COUPLING (MOAC) OVER MEANDERING FRONTS AND EDDIES IN THE FORM OF SURFACE CURRENT DRAG AND SST MODULATIONS OF SURFACE WINDS. RECENT STUDIES SUGGEST THAT THE MOAC EFFECT PLAYS A MAJOR ROLE IN REGULATING MESOSCALE EDDY KINETIC ENERGY (EKE) AND HENCE THE MEAN OCEAN CURRENTS. HISTORICAL HINDCASTS WITH OCEAN MODELS FORCED BY OBSERVED WINDS REVEALED THAT LARGE-SCALE WIND FLUCTUATIONS DRIVE OCEAN CIRCULATION CHANGES IN THE EQUATORIAL PACIFIC AND KUROSHIO EXTENSION. AS THE RESOLUTION OF OCEAN MODELS INCREASES TO RESOLVE SHARP JETS AND EDDIES A DILEMMA EMERGES: THE MOAC EFFECT IN THE SCATTEROMETER-OBSERVED WINDS DOES NOT MATCH THE FRONTS AND EDDIES SIMULATED IN THE MODELS AS EDDIES ARE GENERATED SPONTANEOUSLY. WE PROPOSE TO DEVELOP A FILTER THAT ADJUSTS THE MOAC EFFECT TO MODEL-GENERATED EDDIES AND THEREBY ENABLES OCEAN-ATMOSPHERE INTERACTIONS ON THE MESOSCALE WHILE RETAINING LARGE-SCALE AND OROGRAPHICALLY INDUCED WIND VARIATIONS. THIS MOAC FILTER BUILDS ON OUR RECENT WORK THAT ESTABLISHED THE MOAC DEPENDENCY ON HORIZONTAL SCALE AND LARGE-SCALE WINDS. WE WILL PERFORM MULTI-DECADAL EDDY-RESOLVING OCEAN HINDCASTS BY FORCING THIS MOAC-ENABLED MODEL OF THE PACIFIC OCEAN WITH OUR SATELLITE-DERIVED WIND FORCING. WE WILL CONDUCT EDDY ENERGY AND FLUX ANALYSES TO STUDY HOW THE MOAC AFFECTS OCEAN EDDY PROPERTIES AND FEEDS BACK ON THE OCEAN MEAN FLOW IN THREE DYNAMICALLY DISTINCT REGIONS OF THE PACIFIC: THE EQUATORIAL FRONT KUROSHIO EXTENSION AND CALIFORNIA CURRENT SYSTEM. THE HINDCAST WILL BE CRITICALLY COMPARED TO INDEPENDENT OCEAN OBSERVATIONS (E.G. BY SATELLITE ALTIMETRY AND ARGO) TO STUDY THE DYNAMICS OF SUBSEASONAL TO DECADAL VARIABILITY IN THE OCEAN AND EVALUATE THE MOAC EFFECT. SATELLITE SCATTEROMETRY ALSO REVEALED UNPRECEDENTED DETAILS OF OROGRAPHICALLY INDUCED WIND JETS AND THEIR TEMPORAL VARIATIONS. THESE WIND JETS LEAVE MARKED IMPRINTS ON THE OCEAN CIRCULATION AND PLAY AN IMPORTANT ROLE IN EDDY GENERATION. WE PROPOSE TO STUDY INTERANNUAL MODULATIONS OF WIND JET-INDUCED OCEAN CURRENTS AND EDDY GENERATION TAKING ADVANTAGE OF THE HIGH RESOLUTION OFFERED BY SCATTEROMETRY AND THE MULTI-DECADAL EDDY RESOLVING OCEAN HINDCAST. OUR PROPOSED RESEARCH WILL DEEPEN PHYSICAL UNDERSTANDING OF WIND-DRIVEN OCEAN CIRCULATION VARIABILITY AND THE ROLE OF SHORT-SCALE OCEAN VECTOR WINDS THAT ARE POORLY RESOLVED BY TRADITIONAL WIND OBSERVATIONS THEREBY CONTRIBUTING TO THE PRIORITIES OF THE NASA OVWST CALL. THE MOAC FILTER FROM THE PROJECT ALONG WITH THE MOAC FILTERED SATELLITE WIND STRESS WILL BE MADE AVAILABLE FOR EASY IMPLEMENTATION IN OTHER EDDY-RESOLVING OCEAN MODELS. OUR PROPOSED RESEARCH THUS ADDRESSES A LONGSTANDING AND FUNDAMENTAL ISSUE IN SCATTEROMETRY: HOW SCATTEROMETER-DERIVED WINDS SHOULD BE UTILIZED TO FORCE OCEAN MODELS GIVEN THE MISMATCH OF THE OBSERVED MOAC IMPRINT TO THE MESOSCALE EDDIES THAT SPONTANEOUSLY ARISE IN OCEAN MODELS.