WE PROPOSE TO QUANTIFY THE STRATOSPHERIC IMPACT ON TROPOSPHERIC OZONE INTERANNUAL VARIABILITY AND TRENDS SINCE 1990 AND THE CONTRIBUTIONS OF STRATOSPHERIC AND ANTHROPOGENIC EFFECTS ON TROPOSPHERIC OZONE RADIATIVE FORCING AND ON REGIONAL AIR QUALITY. WE ARE RESPONDING TO AREA A OF ROSES-2016 ANNOUNCEMENT NNH16ZDA001N WHICH CALLS FOR STUDIES CONCERNING THE EVOLUTION OF TROPOSPHERIC OZONE AND THEIR IMPACTS ON CLIMATE AND AIR QUALITY AND USE OF AURA DATA TO TRACK CHANGES IN STRATOSPHERIC AND TROPOSPHERIC COMPOSITION DETERMINE THE EXCHANGE OF TRACER GASES WITHIN THE TROPOSPHERE BETWEEN THE STRATOSPHERE AND TROPOSPHERE AND ESTIMATE THE TRANSPORT PROPERTIES OF THE STRATOSPHERE AND UPPER TROPOSPHERE. WE PROPOSE TO CARRY ON AN INTEGRATED ANALYSIS USING THE SUITE OF DATA DERIVED FROM AURA (TES AND MLS O3 MERRA-2 ASSIMILATION OF OMI/MLS THE COMBINED TES/MLS CO MLS H2O OMI NO2) OZONESONDE MEASUREMENTS AND A SERIES OF MODEL SIMULATIONS WITH THE GLOBAL MODELING INITIATIVE (GMI) STRATOSPHERE-TROPOSPHERE CHEMICAL MECHANISM AND MERRA-2 METEOROLOGY INCLUDING A STRATOSPHERIC OZONE TRACER. OUR ANALYSIS INCLUDES THE ENTIRE TROPOSPHERE WITH A FOCUS ON STRATOSPHERE-TROPOSPHERE EXCHANGE (STE) EFFECTS ON UPPER TROPOSPHERIC AND NEAR SURFACE OZONE. WE SPECIFICALLY PROPOSE (A) TO QUANTIFY THE SPATIAL DISTRIBUTION AND VERTICAL EXTENT OF IMPACTS OF STE ON TROPOSPHERIC OZONE AND ASSOCIATED INTERANNUAL VARIATIONS AND TRENDS; (B) TO QUANTIFY OZONE RADIATIVE FORCING SINCE 1990 DUE TO STE CHANGES AND ITS RELATIVE IMPORTANCE TO RADIATIVE FORCING FROM ANTHROPOGENIC OZONE; (C) TO IDENTIFY GLOBAL HOTSPOTS OF DEEP STE EVENTS AND THEIR IMPACT ON REGIONAL AIR QUALITY. THIS PROJECT WILL GREATLY IMPROVE OUR UNDERSTANDING OF THE VERTICAL EXTENT OF STE IMPACTS ON INTERANNUAL VARIATIONS AND TRENDS OF TROPOSPHERIC OZONE AS WELL AS RESULTING VARIATIONS IN RADIATIVE FORCING OF THE CLIMATE SYSTEM. THEREFORE THE SUCCESSFUL COMPLETION OF THIS RESEARCH CAN BE EXPECTED TO IMPROVE OUR ABILITY TO PREDICT THE FUTURE EVOLUTION OF RADIATIVE FORCING FROM OZONE IN A CHANGING CLIMATE. IN ADDITION THE INSIGHTS GAINED FROM MODEL ANALYSIS WILL BENEFIT THE ONGOING ATMOSPHERIC TOMOGRAPHY MISSION (ATOM) WHICH SYSTEMATICALLY MEASURES VERTICAL PROFILES OF REACTIVE GASES AND AEROSOL MEASURE SPANNING THE PACIFIC OCEAN AND ATLANTIC OCEAN ESPECIALLY IN AREAS CONSIDERED REMOTE AND CLEAN.