The Megacities Carbon Project (MCP) is an interagency pilot activity being established in Los Angeles and Paris (and potentially Sao Paulo) with the overarching goal of developing and testing robust techniques for monitoring distributions and trends of anthropogenic carbon emissions attributed to the world�??s megacities and characterizing the carbon dynamics spanning their complex urban-suburban-rural landscapes (megacities.jpl.nasa.gov). The LA measurement network currently being deployed consists of 16 monitoring stations offering continuous in-situ and daylight remote- sensing observations of atmospheric CO2, carbon monoxide (CO), and/or methane (CH4) mixing ratios. The four objectives of the proposed work are to: (1) complete, integrate, test, and validate the LA megacity observational network and modeling framework �?? resulting in an urban test-bed that supports the research goals of this task and others by the broader community; (2) apply the test-bed to characterize the spatio- temporal nature of the urban dome of total CO2 and FFCO2 concentrations (secondary goal: CH4) spanning the complex urban-suburban-agricultural-rural landscape, (3) apply the test-bed and existing satellite observations to evaluate the joint application of those assets and future remote-sensing of CO2 and CO and in-situ 14C observations to monitor urban FFCO2 emissions, and (4) apply the test-bed to test hypotheses regarding emission ratios in space and time across the domain as well as between in- situ point measurements and remotely-sensed column measurements (to enable future independent testing of bottom-up inventories).