THE RANGE OF ESTIMATED EQUILIBRIUM CLIMATE SENSITIVITY (ECS) HAS REMAINED LARGELY UNCHANGED FOR NEARLY HALF A CENTURY. SUCH UNCERTAINTY HINDERS THE DEVELOPMENT OF POLICIES FOR MITIGATING AND ADAPTING TO FUTURE CHANGES IN CLIMATE. THE INABILITY TO MAKE SIGNIFICANT PROGRESS IN CONSTRAINING ECS REFLECTS IN PART THE LACK OF OBSERVATIONS WITH SUFFICIENT LONGEVITY AND FIDELITY TO ACCURATELY QUANTIFY THE RELEVANT RADIATIVE FEEDBACKS THAT DETERMINE ECS. IN THIS STUDY WE SEEK TO ADDRESS THIS PROBLEM USING "RADIATIVE KERNELS" TO DECOMPOSE INDIVIDUAL FEEDBACK CONTRIBUTIONS TO THE SURFACE AND TOP-OF-ATMOSPHERE (TOA) RADIATIVE FLUXES USING THE ~20 YEAR RECORD OF EOS/SNPP OBSERVATIONS. IN DOING SO WE AIM TO QUANTIFY THE STRENGTH AND THE SPATIAL/TEMPORAL CHARACTERISTICS OF THESE FEEDBACKS. THESE RESULTS WILL BE USED TO EVALUATE CMIP6 MODEL SIMULATIONS UNDER A VARIETY OF FORCING SCENARIOS TO BETTER UNDERSTAND THE IMPLICATIONS OF THE CHANGES OBSERVED BY EOS/SNPP FOR LONGER-TERM CLIMATE CHANGE. RADIATIVE KERNELS DESCRIBE THE DIFFERENTIAL RESPONSE OF RADIATIVE FLUXES TO INCREMENTAL CHANGES IN THE FEEDBACK VARIABLES (E.G. CLOUDS WATER VAPOR TEMPERATURE OR SURFACE ALBEDO) AND ENABLE ONE TO DECOMPOSE OBSERVED CHANGES IN SURFACE AND TOP-OF-ATMOSPHERE RADIATIVE FLUXES INTO CONTRIBUTIONS FROM THE INDIVIDUAL FEEDBACKS. PREVIOUS NASA FUNDING TO THE PI SUPPORTED THE DEVELOPMENT OF AN OBSERVATIONALLY BASED SET OF RADIATIVE KERNELS FROM CLOUDSAT/CALIPSO. ALTHOUGH MANY STUDIES HAVE INVESTIGATED CHANGES IN SUCH VARIABLES FROM EOS MEASUREMENTS WE STRIVE FOR A MORE HOLISTIC INTEGRATION THAT USES RADIATIVE KERNELS TO BETTER UNDERSTAND THE UNDERLYING CAUSE OF CHANGES IN TOA AND SURFACE RADIATIVE FLUXES OBSERVED BY CERES. BY INTEGRATING EOS MEASUREMENTS ACROSS MULTIPLE SENSORS AND PLATFORMS WE AIM TO QUANTIFY THE IMPLICATIONS OF THE CHANGES IN CLIMATE OBSERVED DURING THE EOS ERA ON THE RADIATIVE FEEDBACKS WITHIN THE CLIMATE SYSTEM. THE RESULTS FROM THIS ANALYSIS WILL BE USED TO EVALUATE AND HOPEFULLY BETTER CONSTRAIN THE REPRESENTATION OF FEEDBACK PROCESSES IN COUPLED OCEAN-ATMOSPHERE MODELS. SPECIFICALLY WE SEEK TO USE RADIATIVE KERNELS DEVELOPED FROM CLOUDSAT/CALIPSO IN COMBINATION WITH TEMPERATURE AND HUMIDITY PROFILES FROM AIRS SURFACE AND TOA RADIATIVE FLUXES FROM CERES AND CLOUD AEROSOL AND SURFACE ALBEDO PRODUCTS FROM MODIS TO QUANTIFY THE SURFACE AND TOA RADIATIVE FEEDBACKS. THE PROPOSED WORK WILL ALSO INCLUDE AN OBSERVATIONAL EVALUATION OF THE RADIATIVE KERNEL METHOD USING CERES AND DOE/ARM OBSERVATIONS. THE TASKS TO BE COMPLETED UNDER THIS PROPOSAL INCLUDE: * EVALUATE CLOUDSAT RADIATIVE KERNELS USING CERES AND DOE/ARM OBSERVATIONS. * DECOMPOSE THE CHANGES IN RADIATION BUDGET INTO CONTRIBUTIONS FROM INDIVIDUAL FEEDBACK VARIABLES USING CLOUDSAT KERNELS AND EOS/ SNPP RETRIEVALS. * COMPARE KERNEL-SIMULATED FLUX ANOMALIES TO CERES OBSERVATIONS. * ANALYZE THE TEMPORAL AND SPATIAL CHARACTERISTICS OF THE OBSERVED RADIATIVE FEEDBACKS. * COMPARE RADIATIVE FEEDBACKS DERIVED FROM EOS/SNPP WITH CMIP6 MODEL SIMULATIONS. BY DOCUMENTING THE STRENGTH OF RADIATIVE FEEDBACKS OBSERVED BY EOS/SNPP THE PROPOSED WORK DIRECTLY ADDRESSES THE PROGRAM PRIORITIES OF "MULTIMISSION AND MULTISENSOR INNOVATIVE RESEARCH THAT CAN BE USED TO QUANTIFY CHANGE CHARACTERIZE PROCESSES AND EXAMINE FUNCTION WITHIN THE EARTH SYSTEM OVER TIME."