THE SUB-MESOSCALE OCEAN DYNAMICS EXPERIMENT (S-MODE) IS A FIVE-YEAR MISSION DESIGNED TO TEST THE HYPOTHESIS THAT SUBMESOSCALE OCEAN DYNAMICS MAKE IMPORTANT CONTRIBUTIONS TO VERTICAL EXCHANGE OF CLIMATE AND BIOLOGICAL VARIABLES IN THE UPPER OCEAN. S-MODE WAS COMPETITIVELY SELECTED FOR FUNDING IN RESPONSE TO ROSES 2017 SOLICITATION NNH17ZDA001N UNDER NASA S EARTH VENTURE SUBORBITAL-3 PROGRAM. A MAJOR DIFFICULTY IN SIMULATING EARTH S CLIMATE SYSTEM IS THAT THERE ARE INTERACTIONS ACROSS SCALES SO THAT THE LARGE TIME AND SPACE SCALES CAN BE SENSITIVE TO PROCESSES ON SMALL SCALES. AS THE COMPUTATIONAL RESOLUTION OF GLOBAL OCEAN MODELS HAS IMPROVED SCIENTISTS HAVE BEGUN TO SUSPECT THAT KILOMETER-SCALE EDDIES AND FRONTS CALLED SUBMESOSCALE VARIABILITY HAVE A NET EFFECT ON OCEAN-ATMOSPHERE HEAT EXCHANGE THAT IS LARGER THAN THE HEATING FROM THE GREENHOUSE EFFECT. STATEOF- THE-ART COMPUTER MODELS AGREE IN PREDICTING THAT THESE EDDIES HAVE IMPORTANT LONG-TERM EFFECTS ON THE UPPER-OCEAN BUT THEIR PREDICTIONS ARE SENSITIVE TO RELATIVELY SMALL DETAILS IN MODEL PHYSICS AND IMPLEMENTATION. THE RESOLUTION AND DETAIL OF THESE SIMULATIONS HAS SURPASSED OUR ABILITY TO GROUND TRUTH THEM WITH SPACEBORNE OR IN SITU SENSORS. THERE IS THUS A PRESSING NEED FOR A COMPREHENSIVE BENCHMARK DATA SET ON THESE SUBMESOSCALE MOTIONS TO ADDRESS THIS IMPORTANT SOURCE OF UNCERTAINTY IN SIMULATING THE GLOBAL OCEAN. TESTING THIS HYPOTHESIS WILL REQUIRE COORDINATED APPLICATION OF NEWLY-DEVELOPED IN SITU AND REMOTE SENSING TECHNIQUES AND IT WILL PROVIDE AN UNPRECEDENTED VIEW OF THE PHYSICS OF SUBMESOSCALE EDDIES AND FRONTS AND THEIR EFFECTS ON VERTICAL TRANSPORT IN THE UPPER OCEAN. S-MODE WILL USE MEASUREMENTS FROM A NOVEL COMBINATION OF PLATFORMS AND INSTRUMENTS ALONG WITH DATA ANALYSIS AND MODELING TO TEST THE HYPOTHESIS. IN A REGION EXTENDING 300KM OFFSHORE OF SAN FRANCISCO S-MODE WILL COLLECT SIMULTANEOUS MEASUREMENTS USING SEVERAL AIRBORNE INSTRUMENTS INCLUDING THE NASA DOPPLERSCATT INSTRUMENT THE NASA PRISM INSTRUMENT THE SCRIPPS INSTITUTION OF OCEANOGRAPHY MASS INSTRUMENT AND THE UCLA MOSES INSTRUMENT. IN CONJUNCTION WITH THE MEASUREMENTS FROM AIRCRAFT (THE NASA AFRC KING AIR B200 THE NASA JSC G-V AND A COMMERCIAL TWIN OTTER DHC-6) IN SITU DATA WILL BE OBTAINED USING SURFACE DRIFTERS WAVE-PROPELLED AUTONOMOUS VEHICLES LAGRANGIAN FLOATS THAT FOLLOW THE 3D FLOW VERTICALLY PROFILING AUTONOMOUS UNDERWATER VEHICLES AND A UNOLS RESEARCH VESSEL. THIS PROPOSAL SETS OUT THE WORK AND BUDGET FOR THE BAER INSTITUTE PERSONNEL IN SUPPORTING THE SMODE MISSION. PERSONNEL FROM BAER INSTITUTE WILL PLAY INTEGRAL ROLES IN THE FIELD DEPLOYMENT MANAGEMENT (FDM) TEAM FROM NASA AMES RESEARCH CENTER S EARTH SCIENCE PROJECT OFFICE (ESPO). THE FDM TEAM WILL WORK WITH THE LEAD PRINCIPAL INVESTIGATOR FROM WOODS HOLE OCEANOGRAPHIC INSTITUTION TO MANAGE THE INVESTIGATION IMPLEMENT THE FIELD DEPLOYMENTS AND COORDINATE RELEVANT ASPECTS OF PROGRAMMATIC REPORTING AT INVESTIGATION STATUS REVIEWS.