OBJECTIVESTWO NEW TYPES OF INFRARED IMAGING RADIOMETERS DESIGNED FOR THE ACCURATE MEASUREMENTS OF SEA-SURFACE TEMPERATURE (SST) ARE COMPONENTS OF TWO NEW SERIES OF EUROPEAN EARTH OBSERVATION SATELLITES. THE FIRST IS THE SEA AND LAND SURFACE TEMPERATURE RADIOMETER(SLSTR) ON THE CONSTELLATION OF SENTINEL-3 SATELLITES AND THE SECOND IS THE METIMAGE SENSOR ON THE EUROPEAN ORGANIZATION FOR THEEXPLOITATION OF METEOROLOGICAL SATELLITES (EUMETSAT) POLAR SYSTEM-SECOND GENERATION (EPS-SG). THE FIRST SLSTR WAS LAUNCHED IN FEBRUARY 2016 AND THE SECOND IS PLANNED FOR LAUNCH IN 2017. THE SECOND PAIR OF SENTINEL-3S WILL BE LAUNCHED IN THE 2020S. THE FIRST METIMAGE RADIOMETER WILL BE LAUNCHED IN 2021. IT IS EXPECTED THAT THESE NEW SENSORS ESPECIALLY THE SLSTRS WILL BE MORE ACCURATE THAN THOSE CURRENTLY ON ORBIT AND OBJECTIVE OF THIS RESEARCH IS TO DETERMINE THE ACCURACIES OF THE SLSTR SSTS USING COMPARISONSWITH MEASUREMENTS TAKEN BY HIGH-ACCURACY SHIPBOARD INFRARED RADIOMETERS. THIS APPROACH BUILDS ON OUR EXPERTISE DEVELOPED OVER MANY YEARS IN ASSESSING AND IMPROVING THE ACCURACIES OF MODIS AND VIIRS SSTS ON US SATELLITES. SUBSEQUENT COMPARISONS BETWEEN SLSTR MEASUREMENTS AND THOSE OF THE MODISS AND VIIRS WILL LEAD TO IMPROVEMENTS IN THE ACCURACY OF THE SSTS DERIVED FROM MODISS AND VIIRS. FOR MOST OF THE DURATION OF THIS PROJECT METIMAGE WILL BE UNDERGOING DESIGN REFINEMENTS AND THE PI WILL HAVETHE OPPORTUNITY TO INFLUENCE THE FINAL CHARACTERISTICS OF THE INSTRUMENT; THE FIRST METIMAGE WILL BE LAUNCHED IN THE FINAL YEAR OF THE PROJECT ALLOWING US TO CONDUCT THE INITIAL ASSESSMENT OF ITS ACCURACY.METHODSBUILDING ON THE PROVEN APPROACH OF DETERMINING THE ACCURACIES OF SSTS DERIVED FROM THE MODISS AND VIIRS ON US POLAR ORBITING SATELLITES AND IMPROVING THE METHODS USED TO DERIVE THE SSTS FROM THE SATELLITE MEASUREMENTS WE WILL COMPARE THE MEASUREMENTS OF THE SLSTR WITH THOSE OF SHIPBOARD RADIOMETERS. THE SHIPBOARD RADIOMETERS ARE VERY WELL CALIBRATED AND PROVIDE IMPORTANT REFERENCE DATA FOR THIS TASK. THE RADIOMETERS ARE INSTALLED ON CRUISE SHIPS COMMERCIAL SHIPS AND RESEARCH VESSELS. WE WILL THAN MAKECOMPARISON BETWEEN THE SLSTR DATA AND THE MEASUREMENTS OF MODIS AND VIIRS WITH THE INTENTION OF LEARNING HOW TO IMPROVE THE ACCURACIES MODIS AND VIIRS SSTS THROUGHOUT THE GLOBAL OCEANS.SIGNIFICANCESEA-SURFACE TEMPERATURE IS VERY IMPORTANT IN STUDYING THE OCEAN ATMOSPHERE AND THE CLIMATE SYSTEM. SST IS ALSO USED ON WEATHER FORECASTING MODELS. THE MOST STRINGENT ACCURACY REQUIREMENT FOR SATELLITE-DERIVED SST IS FOR CLIMATE RESEARCH; IT IS AN ESSENTIAL CLIMATE VARIABLE. THE GENERATION OF CLIMATE DATA RECORDS (CDRS) OF SATELLITE-DERIVED SSTS REQUIRES THE COMBINATION OF MEASUREMENTSFROM MANY SATELLITE SENSORS. THE SHIPBOARD RADIOMETERS HAVE CALIBRATIONS THAT ARE TRACEABLE TO NATIONAL TEMPERATURE STANDARDS AND USING THEIR DATA TO DETERMINE THE ACCURACIES OF THE SATELLITE SSTS PROVIDES THE MECHANISM FOR GENERATING SST CDRS FROM MULTIPLE SATELLITE INSTRUMENTS. THE RESEARCH PROPOSED HERE IS A CRITICAL STEP IN INCORPORATING THE MEASUREMENTS FROM THE NEW SENSORS (SLSTRS AND METIMAGES) WITH THOSE THAT ARE ALREADY WELL ESTABLISHED (MODISS AND VIIRS). THUS THIS IS AN IMPORTANT STEP IN GENERATINGCDRS OF SST FROM MULTIPLE SATELLITE RADIOMETERS.