The Megacities Carbon Project is developing, testing, and improving robust methods for assessing carbon emissions and monitoring the atmospheric trends of carbon attributed to the world’s largest cities.
Cities Produce 70% of All Fossil-Fuel CO2 Emissions
A 10-km-resolution map indicates the distribution and intensity of fossil fuel CO2 emission sources. The regions with greatest emission intensity are indicated by red and black (urbanized areas and associated large power plants). The black circles indicate a vision for future surface measurement networks concentrated within the 23 existing megacities. Blue circles indicate the 14 additional megacities projected to exist by 2025. The dashed rectangles indicate the fields of regard of three remote-sensing instruments that if hosted on geostationary satellites would offer sustained, wall-to-wall mapping of nearly every emission source. The satellite and surface network data, integrated with improved high-resolution emission estimates would provide a robust system for assessing and informing policies. Map: (EDGAR version 4.0) 2009.
Megacities observing system for Los Angeles
In-situ sensors located around the LA basin provide continuous, high accuracy measurements of greenhouse gas (GHG) mixing ratios of CO2, CH4, and CO. A remote-sensing instrument on Mt. Wilson provides multiple scans per day of the basin to measure slant-column mixing ratios. Another remote-sensing instrument at Caltech provides continuous daytime measurements of column mixing ratios. Aircraft and mobile laboratories provide infrequent but intensive measurements of mixing ratios. Satellites are beginning to provide remote-sensing measurements of LA. Other instruments (not shown) measure winds and boundary layer height.
Monitoring Urban Greenhouse Gas Emissions from Space
From right to left: NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite provides nearly global coverage that periodically samples the CO2 over a subset of cities. The Japanese Space Agency's GOSAT satellite makes observations for a subset of cities with coarser resolution than OCO-2. NASA's OCO-3 payload on the International Space Station (status TBD) includes a "city-mode" that would have the ability to map most of the world's cities and power plants on a regular basis. Finally, the next generation of remote-sensing instruments, if deployed on 3 satellites in geostationary orbits would provide near-continuous, complete mapping of nearly every urban area on earth.
Los Angeles Basin Onroad CO2 Emissions
Preliminary estimate of annual on-road CO2 emissions for 2010 for the five counties of the LA megacity. The lower left figure is a zoomed-in view of southern LA county ( local neighborhood roads are not shown). This is based on annual average weekly traffic data from Southern California Association of Governments (SCAG) and modeled annual CO2 emissions for different road types from US Environmental Protection Agency’s (EPA) National Mobile Inventory Model (NMIM). The annual county-specific CO2 emissions are allocated to each road segment based on its type and annual vehicle miles travelled (VMT). VMT is the number of vehicles on a particular road segment multiplied by the road length.
Tracking the Carbon Emissions of Megacities
This animation shows a global map of fossil-fuel CO2 emissions for the year 2010 derived from satellite imagery of night-lights and other data (courtesy Tom Oda - CSU/NOAA in collaboration with NIES). A global urban carbon monitoring system would combine surface measurement networks in the world's largest cities (highlighted here) and satellite observations of nearly all urban areas. The surface grid squares illustrate the surface footprint of future geostationary satellites that could be focused on the 2-3% of land surface area producing the majority of emissions. Animation courtesy: NASA's Goddard Space Flight Center, Conceptual Image Lab.
Satellites Observe CO2 from Los Angeles
The following animation illustrates the collection of Orbiting Carbon Observatory (OCO-2) "target mode" data over Caltech in Pasadena. Caltech is one of 19 sites around the world that track the sun to collect up-looking measurements of CO2 to validate OCO-2 remote sensing measurements and link them to international standards of CO2. During a Target Mode pass, the spacecraft points towards Caltech from far away, and with a small sweeping motion, stays focused on the target (Caltech) as the spacecraft moves overhead and past the target over a period of about 15 minutes. The animation shows that a large portion of the LA basin is sampled - with the most dense, overlapping sets of data collected around Caltech.