WE PROPOSE TO INVESTIGATE THE GLOBAL INTERNAL TIDE-DRIVEN OCEAN MIXING BY COMBINING TWO COMPLEMENTARY TECHNIQUES: SATELLITE ALTIMETRY AND HYBRID COORDINATE OCEAN MODEL (HYCOM) SIMULATIONS. THE RESULTS WILL BE COMPARED WITH FIELD MEASUREMENTS MADE BY SHIPBOARD MICROSTRUCTURE AND CTD INSTRUMENTS. INTERNAL TIDES PROVIDE ABOUT HALF OF THE REQUIRED POWER FOR DIAPYCNAL MIXING IN THE OCEAN INTERIOR AND THUS PLAY AN IMPORTANT ROLE IN MODULATING THE GLOBAL OCEAN CIRCULATION AND CLIMATE. DESPITE DECADES OF FIELD MEASUREMENTS OCEAN MIXING REMAINS A CHALLENGING PROBLEM IN PHYSICAL OCEANOGRAPHY. WE HAVE CONSTRUCTED GLOBAL INTERNAL TIDE MAPS USING MULTI-YEAR MULTI-SATELLITE ALTIMETER DATA AND A NOVEL PLANE-WAVE FIT METHOD. LONG-RANGE INTERNAL TIDES ARE OBSERVED TO PROPAGATE OVER THOUSANDS OF KM FROM ENERGETIC GENERATION SITES IDENTIFIED BY EGBERT AND RAY (2000 2001). HYCOM IS A GLOBAL HIGH-RESOLUTION NUMERICAL MODEL WITH BOTH TIDAL AND ATMOSPHERIC FORCING AND WILL BE USED TO ESTIMATE THE INCOHERENT INTERNAL TIDES MISSED BY SATELLITE ALTIMETRY. BY COMBINING THESE TWO TECHNIQUES WE ARE ABLE TO MAP INTERNAL TIDE DISSIPATION FROM SPACE BY ADDRESSING THESE THREE MAJOR CHALLENGES: (1) INCOHERENT INTERNAL TIDES (2) INTERFERENCE OF MULTIPLE INTERNAL TIDAL WAVES AND (3) TEMPORAL VARIABILITY. WE HAVE FOUR SPECIFIC RESEARCH OBJECTIVES. (1) WE WILL COMPUTE THE ENERGY AND FLUX OF GLOBAL OPEN-OCEAN INTERNAL TIDES FROM SATELLITE ALTIMETRY AND HYCOM. OUR CALCULATIONS WILL INCLUDE THE FOUR LARGEST TIDAL CONSTITUENTS (M2 S2 O1 AND K1) AND THE TWO LOWEST BAROCLINIC MODES. (2) WE WILL QUANTIFY HOW MUCH INTERNAL TIDAL ENERGY REACHES AND LEAVES THE COASTAL REGIONS. (3) WE WILL QUANTIFY WHERE INTERNAL TIDES DISSIPATE IN THE GLOBAL OCEAN USING THE GLOBAL MAPS OF INTERNAL TIDE ENERGY FLUXES FROM SATELLITE ALTIMETRY AND HYCOM. (4) WE WILL INVESTIGATE THE SEASONALITY OF INTERNAL TIDES AND DISSIPATION. THIS PROPOSAL RESPONDS TO THE SOLICITATION OF THE NASA PO PROGRAM TO EXPAND OUR SPATIAL AND TEMPORAL ESTIMATES OF OCEAN MIXING. THE COMBINATION OF SATELLITE ALTIMETRY AND HYCOM OFFERS A NOVEL APPROACH TO TRACK LONG-RANGE INTERNAL TIDES FROM SPACE COMPLEMENTING PREVIOUS EFFORTS BY FIELD MEASUREMENTS. THIS PROPOSAL WILL IMPROVE OUR UNDERSTANDING OF THE SPATIAL AND TEMPORAL VARIATIONS OF INTERNAL TIDE AND OCEAN MIXING. IT WILL LEAD TO IMPROVED GLOBAL INTERNAL TIDE MODELS THAT ARE MUCH NEEDED BY NASA S NEXTGENERATION ALTIMETER SWOT. THE NEW KNOWLEDGE OF INTERNAL TIDES AND MIXING IS USEFUL TO THE NASA-SUPPORTED PROJECT ECCO2 WHICH IS INCORPORATING THE TIDE AND INTERNAL TIDE COMPONENTS.