CLOUDS HAVE IMPORTANT RADIATIVE EFFECTS ON THE ATMOSPHERE-OCEAN SYSTEM. IN PARTICULAR CLOUDS INFLUENCE LARGE-SCALE ATMOSPHERIC DYNAMICS THROUGH HEATING OR COOLING OF THE ATMOSPHERE AND INFLUENCE SEA-SURFACE-TEMPERATURE (SST) THROUGH THEIR EFFECTS ON THE SURFACE ENERGY BUDGET. PREDICTING THE CLOUD RESPONSE TO GLOBAL WARMING IS THEREFORE OF GREAT SOCIETAL IMPORTANCE BECAUSE CLOUDS MAY CHANGE IN A WAY THAT EITHER AMPLIFIES OR ENHANCES GLOBAL WARMING BY REDUCING OR INCREASING THE AMOUNT OF RADIATION THAT EARTH SHEDS TO SPACE (A POSITIVE OR NEGATIVE FEEDBACK RESPECTIVELY). YET THE CLOUD FEEDBACK REMAINS THE GREATEST SOURCE OF UNCERTAINTY IN GLOBAL WARMING PROJECTIONS. OBSERVATIONAL RECORDS PROVIDE AN OPPORTUNITY TO STUDY CLOUD FEEDBACKS THAT OPERATE IN THE NATURAL SYSTEM ON INTERANNUAL TO DECADAL (LESS THAN 1 YEAR TO 10 YEAR) TIME SCALES WHICH MAY LEAD TO A GREATER UNDERSTANDING OF HOW CLOUD FEEDBACKS SHOULD OPERATE IN GLOBAL CLIMATE SIMULATIONS. PREVIOUS STUDIES HAVE FOUND THAT CLOUD FEEDBACKS HAVE AN IMPORTANT ROLE IN ASSOCIATION WITH EXTRATROPICAL ATMOSPHERIC VARIABILITY AS WELL AS IN ASSOCIATION WITH TROPICAL SST VARIABILITY. HOWEVER IT IS UNCLEAR WHETHER CLOUD FEEDBACKS ARE IMPORTANT IN THE FORCING OF TROPICAL SST VARIABILITY BY EXTRATROPICAL ATMOSPHERIC VARIABILITY WHICH IS AN IMPORTANT PATHWAY WHEREBY EXTRATROPICAL PROCESSES AFFECT TROPICAL CLIMATE. THE GOAL OF THE PROPOSED RESEARCH PROJECT IS TO IMPROVE OUR UNDERSTANDING OF THE ROLE OF CLOUDS IN THE FORCING OF INTERANNUAL TO DECADAL TROPICAL SST VARIABILITY BY EXTRATROPICAL ATMOSPHERIC VARIABILITY IN THE NORTHERN HEMISPHERE. THE WORK WILL HAVE TWO PARTS. IN THE FIRST PART I WILL DIAGNOSE CLOUD RADIATIVE EFFECTS (CRE) ASSOCIATED THE MODES OF VARIABILITY THAT "BRIDGE" EXTRATROPICAL ATMOSPHERIC VARIABILITY TO INTERANNUAL TO DECADAL TROPICAL SST VARIABILITY IN THE NORTHERN HEMISPHERE. I WILL USE CRE FROM REMOTELY-SENSED PRODUCTS THAT SPAN MULTIPLE DECADES (1980-2017) AS WELL AS SST FIELDS FROM REANALYSIS PRODUCTS TO DO SO. IN THE SECOND PART I WILL DIRECTLY TEST THE ROLE OF CLOUD FEEDBACKS IN THE FORCING OF TROPICAL SST VARIABILITY BY EXTRATROPICAL ATMOSPHERIC VARIABILITY BY USING GLOBAL CLIMATE MODEL SIMULATIONS THAT HAVE CLOUD FEEDBACKS DISABLED. IN SUMMARY THE PROPOSED RESEARCH PROJECT FITS APPROPRIATELY WITH NASA'S MISSION BECAUSE 1) A RANGE OF NASA PRODUCTS INCLUDING REMOTELY-SENSED CLOUD OBSERVATIONS AND REAANLYSIS PRODUCTS ARE ESSENTIAL TO THE SUCCESS OF THE PROJECT 2) IMPROVED UNDERSTANDING OF THE PROCESSES THAT CONTRIBUTE TO DECADAL TROPICAL SST VARIABILITY MAY LEAD TO IMPROVED DECADAL GLOBAL CLIMATE PREDICTIONS AND REGIONAL CLIMATE PREDICTIONS INCLUDING NORTH AMERICAN DROUGHT AND CHANGES IN HURRICANES AND RAINFALL OVER THE NORTHERN CONTINENTS 3) IMPROVED UNDERSTANDING OF THE PROCESSES THAT CONTRIBUTE TO FORCING OF TROPICAL SST VARIABILITY BY EXTRATROPICAL ATMOSPHERIC VARIABILITY MAY LEAD TO GREATER UNDERSTANDING OF HOW THIS PATHWAY MAY CHANGE IN RESPONSE TO GLOBAL WARMING AND 4) IMPROVED UNDERSTANDING OF CLOUD FEEDBACKS IN THE REAL ATMOSPHERE MAY ELUCIDATE HOW THEY SHOULD OPERATE IN UNFORCED GLOBAL CLIMATE SIMULATIONS AND IN TURN GLOBAL WARMING SIMULATIONS