WE PROPOSE TO USE EXISTING MODELS AND A SUITE OF OBSERVATIONS FROM ORBITAL SUB-ORBITAL AND GROUND-BASED PLATFORMS TO ASSESS AND IMPROVE PREDICTIVE CAPABILITIES FOR ATMOSPHERIC OZONE AND TO BETTER QUANTIFY HOW CLIMATE CHANGE WILL AFFECT BOTH THE RECOVERY OF THE OZONE LAYER AND ENHANCEMENTS IN SURFACE OZONE. OUR INVESTIGATION IS FOCUSED ON THREE TASKS:1) ASSESS THE REPRESENTATION OF CHEMISTRY WITHIN CCMS (COUPLED CHEMISTRY AND CLIMATE MODELS) AND DEVELOP A PROCEDURE WHEREBY METRICS RESULTING FROM THE CHEMICAL EVALUATION CAN BE USED AS WEIGHTS FOR COMBINING THE OZONE TRENDS FROM VARIOUS CCMS IN A MULTI-MODEL WEIGHTED MEAN 2) QUANTIFY THE ROLE OF VERY SHORT LIVED (VSL) CHLOROCARBONS ON THE STRATOSPHERIC CHLORINE BUDGET BY ANALYZING OBSERVATIONS OF CLO IN THE LOWERMOST STRATOSPHERE (LMS) AND EVALUATING THE IMPACT OF VSL HALOGENS (BROMINE AND CHLORINE) ON OZONE TRENDS 3) IMPROVE THE REPRESENTATION OF NOX WITHIN THE EPA CMAQ (ENVIRONMENTAL PROTECTION AGENCY COMMUNITY MULTISCALE AIR QUALITY) MODEL TO IMPROVE SOURCE RECEPTOR RELATIONS OF POLLUTION AND SURFACE OZONE IN THE EASTERN US AND TO EVALUATE THE THEORETICAL UNDERSTANDING OF THE OBSERVED DEPENDENCE OF SURFACE OZONE AND TEMPERATURE (THE CLIMATE PENALTY FACTOR) THE SUCCESSFUL COMPLETION OF THE FIRST TASK WILL CONTRIBUTE TOWARDS THE REDUCTION OF CONSIDERABLE UNCERTAINTY IN THE TIME OF RECOVERY OFSTRATOSPHERIC OZONE TO PARTICULAR LEVELS FOUND BY CURRENT CCM PREDICTIONS. THE SECOND TASK TOGETHER WITH OUR ONGOING EVALUATION OF BROMINE CHEMISTRY IN THE UTLS REGION (SUPPORTED BY THE ROSES 2009 ACMAP CALL) WILL CONTRIBUTE TOWARDS CRITICAL EVALUATION OF THE PHOTOCHEMISTRY OF OZONE IN A REGION WHERE TRENDS ARE NOT WELL UNDERSTOOD. THE THIRD TASK WILL CONTRIBUTE TOWARDS IMPROVEMENT OF THERELIABILITY OF STATE IMPLEMENTATION PLANS (SIPS) REQUIRED FOR AN ANTICIPATED CHANGE IN THE EPA SURFACE OZONE STANDARD AND WILL PROVIDE A THEORETICAL COMPLEMENT TO OUR PRIOR QUANTIFICATION OF THE CLIMATE PENALTY FACTOR.