THE INTERTROPICAL CONVERGENCE ZONE IN THE EASTERN PACIFIC OCEAN FRESH POOL (EPFP) FUELS A COMPLEX SEASONAL CYCLE OF UPPER-OCEAN SALINITY STRATIFICATION AND CURRENTS IN RESPONSE TO BOTH WIND AND PRECIPITATION-EVAPORATION. STRONG HORIZONTAL AND VERTICAL SALINITY GRADIENTS EXIST AS A RESULT OF THE PRESENCE OF FRONTS EDDIES AND FILAMENTS FRESHENING FROM LOCAL PRECIPITATION AND THE SUBSEQUENT ADVECTION OF SURFACE FRESHWATER ANOMALIES. THESE MULTI-SCALE PROCESSES ACT TO STRENGTHEN THE UPPER-OCEAN SALINITY STRATIFICATION CREATING MIXED LAYERS THAT ARE CHARACTERIZED BY SALT-STRATIFIED BARRIER LAYERS AND INVERSIONS. SEA SURFACE TEMPERATURE (SST) ANOMALIES ARE EXPECTED TO BE MEDIATED BY THE PRESENCE OF SALINITY STRATIFICATION SINCE FLUXES OF HEAT FRESHWATER AND MOMENTUM INTO THE OCEAN BECOME TRAPPED IN A THINNER SURFACE LAYER IN ADDITION TO REDUCED ENTRAINMENT COOLING THROUGH THE BASE OF THE MIXED LAYER. THIS SUGGESTS A COMPELLING LINK BETWEEN UPPER-OCEAN SALINITY STRATIFICATION AND AIR-SEA INTERACTION SUCH AS OCCURS THROUGH SST-WIND COUPLING ACROSS A WIDE SPECTRUM OF TEMPORAL AND SPATIAL SCALES WITHIN THE EPFP. UNDERSTANDING THE COMPLEX COUPLED RESPONSE OF THE SALINITY STRATIFICATION IN THE EPFP TO WIND AND BUOYANCY FORCING IS A KEY OBJECTIVE OF THE SPURS-2 EXPERIMENT AND THIS PROPOSAL. OUR HYPOTHESIS IS THAT THE SHALLOW MIXED LAYERS CAUSED BY THE UPPER-OCEAN SALINITY STRATIFICATION PROVIDE A FAVORABLE ENVIRONMENT FOR AIR-SEA INTERACTION TO CONTRIBUTE TO THE WARM SSTS AND FRESHWATER POOLS OF THE EPFP. THE PROPOSED EFFORT ADDRESSES THE LARGE-SCALE AND PROCESS (AIR-SEA INTERACTION UPPER-OCEAN STRATIFICATION) THEMES OF THE SPURS-2 PROCESSES AND SYNTHESIS SOLICITATION AND ADDRESSES THE RESEARCH QUESTION CONCERNING THE CHARACTERIZATION AND PHYSICAL PROCESSES RESPONSIBLE FOR THE EPFP (Q1). OUR LARGE-SCALE ANALYSIS WILL ALSO PROVIDE GUIDANCE FOR UNDERSTANDING HOW THE OCEAN RESPONDS TO CHANGES IN THERMAL AND FRESHWATER FORCING ASSOCIATED WITH A CHANGING CLIMATE (Q2) AND IMPROVEMENT OF MODELS (Q4). THE PROPOSED EFFORT WILL INVOLVE A MULTI-PRONGED APPROACH. FIRST WE WILL CHARACTERIZE THE SURFACE TO PYCNOCLINE SALINITY STRATIFICATION AND QUANTIFY ITS RELATIONSHIP TO IN SITU AND REMOTELY SENSED SST SEA SURFACE SALINITY (SSS) VELOCITY AND AIR-SEA FLUXES OBSERVED DURING THE SPURS-2 FIELD PROGRAM TO UNDERSTAND THE MECHANISMS BY WHICH STRUCTURES OF SALINITY STRATIFICATION SUCH AS BARRIER LAYERS AND INVERSIONS CAN DEVELOP. SECOND WE WILL CONDUCT A REGIONAL ANALYSIS OF AIR-SEA FLUXES AND THEIR RELATIONSHIP TO SALINITY STRATIFICATION IN THE EPFP FROM MEASUREMENTS MADE BY SATELLITES ARGO FLOATS SAILDRONES AND DRIFTERS. IN THE PROCESS WE WILL DETERMINE HOW REPRESENTATIVE THE SHIPBOARD AND MOORED SPURS-2 MEASUREMENTS ARE OF THE SURROUNDING REGIONAL AREA AND ASSESS HOW WELL THE GENERAL GLOBAL OBSERVING SYSTEM ASSETS (ARGO FLOATS DRIFTERS ETC.) COMPUTED AIR-SEA FLUXES AND REMOTELY SENSED SSS AND SST FIELDS CAPTURE THE FEEDBACKS BETWEEN THE ATMOSPHERE THE OCEAN SURFACE AND INTERIOR. FINALLY WE WILL USE THE DATA-ASSIMILATING SIMULATIONS FROM A REGIONAL OCEAN MODELING SYSTEM TO BETTER UNDERSTAND THE MULTI-SCALE PROCESSES THAT MIGHT BE IMPORTANT TO SALINITY STRATIFICATION. OUR OVERARCHING LEGACY WILL BE TO DOCUMENT THE TEMPORAL AND SPATIAL SAMPLING REQUIREMENTS OF THE REMOTELY SENSED AND IN SITU OCEAN OBSERVING NETWORK IN THE EPFP NEEDED TO BETTER CAPTURE THE RELATIONSHIP OF UPPER-OCEAN SALINITY STRATIFICATION AND AIR-SEA INTERACTION. OUR PROJECT CONTRIBUTES TO A DATASET OF SHIPBOARD AND MOORED SALINITY PROFILES FOCUSED AROUND THE CENTRAL SPURS SITE AT 10 DEGN 125DEGW AS WELL AS PRODUCES A UNIFIED UPPER-OCEAN DATASET OF SALINITY STRATIFICATION FOR THE BROADER EPFP CONSTRUCTED FROM ARGO DRIFTERS AND SAILDRONES THAT WILL BE LINKED TO REGIONAL REMOTE-SENSED SST SSS PRECIPITATION AND WIND. THE RESEARCH WILL SUPPORT A POST-DOC AT SCRIPPS INSTITUTION OF OCEANOGRAPHY AND REPRESENTS A COLLABORATIVE EFFORT BETWEEN MANY SPURS-2 PIS.