THE OCO MISSIONS' PRIMARY OBJECTIVES ARE TO MAKE GLOBAL OBSERVATIONS OF CARBON DIOXIDE (CO2) IN THE ATMOSPHERE TO IMPROVE OUR UNDERSTANDING OF THE VARIOUS PROCESSES CONTROLLING ATMOSPHERIC CO2. EXCHANGES BETWEEN THE ATMOSPHERE TERRESTRIAL BIOSPHERE AND OCEAN REMAIN ESSENTIAL CONTROLS THAT ARE DYNAMICALLY RESPONDING TO THE HUMAN PERTURBATION TO THE SYSTEM. THIS PROPOSAL FOCUSES ON THE ANTHROPOGENIC INPUT THAT DRIVES THE LONG-TERM GROWTH OF CO2 AND IS THE ROOT CAUSE OF THE LARGE ATMOSPHERIC PERTURBATION. THE ABILITY OF SPACE-BASED OBSERVATIONS TO DETECT ELEVATED CO2 ASSOCIATED WITH URBAN REGIONS HAS NOW BEEN WELL ESTABLISHED. THE QUESTION OF GREATEST SCIENTIFIC AND SOCIETAL RELEVANCE IS LINKING THESE OBSERVATIONS TO QUANTIFICATION AND ATTRIBUTION OF ANTHROPOGENIC EMISSIONS AND CHANGES IN ANTHROPOGENIC EMISSIONS OVER TIME. MAJOR OBSTACLES HINDERING WIDESPREAD QUANTIFICATION OF ANTHROPOGENIC URBAN EMISSIONS CENTER ON LIMITED OBSERVATIONS ERRORS IN TRANSPORT REPRESENTATION AND THE VARIABLE AND OFTEN LARGE ROLE OF THE URBAN/EXURBAN BIOSPHERE. THIS PROPOSAL TARGETS THESE THREE KEY AREAS OF UNCERTAINTY BY LEVERAGING MORE OCO-2 AND OCO-3 DATA (AS AVAILABLE) EXPLICIT ASSESSMENT AND IMPROVEMENT OF TRANSPORT VIA REMOTE SENSING OBSERVATIONS OF AEROSOLS AND DIRECT BIOSPHERE REPRESENTATION LEVERAGING THE SIF PRODUCT FROM OCO-2 AND OCO-3. BY ADVANCING THE SCIENCE IN THIS MANNER THIS PROPOSAL WILL LEAD TO QUANTIFICATION OF ANTHROPOGENIC EMISSIONS IN EXPANDING DOMAINS (FROM THE MIDDLE EAST TO REGIONS IN MID-LATITUDES WITH SIGNIFICANT VEGETATION) AND THE ADVANCE OF TECHNIQUES TO QUANTIFY EMISSIONS IN REGIONS OF THE GLOBE WHERE SURFACE OBSERVATIONS ARE NOT FEASIBLE. THIS CAPABILITY WILL BE KEY IN OUR UNDERSTANDING OF THE RAPIDLY EVOLVING GLOBAL CARBON CYCLE AS WELL AS TRACKING ANTHROPOGENIC EMISSIONS.