December 1, 2014

  • Join us for our "Understanding the carbon emissions of cities" event this week at the UN climate summit (COP-20) in Lima, Peru. The event is scheduled for 4pm (Lima time) on Friday December 5. For those attending COP-20, the event will be held at the US Center. It will also be recorded and posted to the US Center's Youtube page afterwards (probably by Monday). Riley Duren, Philippe Ciais, Maria de Fatima Andrade, James Whetstone, and Kevin Gurney will describe motivations for urban carbon monitoring, progress with the efforts in Los Angeles, Paris and Sao Paulo, opportunities for expansion to other cities around the world, and how to apply improved carbon data to addressing stakeholder needs.

November 5, 2014

  • Busy week! Our new sites at California State University Fullerton (CSUF) and University of California Irvine (UCI) are coming online. We also began automated air flask sampling at the Granada Hills, USC, and CSUF sites. This sustained sampling program will continue for about 2 years, likely moving to different sites around the basin.

September 2, 2014

  • The Megacities Carbon Project has been selected as a "Project to Watch" for the Big Data Climate Challenge at the UN Climate Summit in NYC on Sept 23. "The Big Data Climate Challenge is a global competition hosted by United Nations Global Pulse, an initiative of the Secretary-General on big data.....The “Projects to Watch” were chosen to highlight particularly innovative uses of big data in emerging topics and geographic regions."

July 25, 2014

  • Present your work at the AGU Fall Meeting in San Francisco Dec 2014! "Quantifying and Attributing Greenhouse Gas Emissions from Urban Systems and Other Complex Areas" (session ID 1961) Abstract deadline is Aug 6, 2014. Submit abstracts at the following link For questions please contact the conveners: Riley Duren, Jocelyn Turnbull, Jim Butler, Irene Xueref-Remy.

July 17, 2014

  • The Compton tower site is now operating. [We'll update the network configuration page shortly]

April 18, 2014

  • Our new measurement site at USC is now operating. This facility provides critical sampling of air in LA's "urban core" and also serves as a testbed for evaluating roof-top sensing methods. Many thanks to Professor Jefferey Sellers (Political Science and Environmental Studies), Halli Bovia (Office of Sustainability) and George Huber (Facilities Management Services) for all their help! [We'll update the network configuration page shortly]

Dec 4, 2013

  • Please join us at the Fall Meeting of the American Geophysical Union in San Francisco for our sessions on Dec 12 and 13 on "Measuring and Modeling the Greenhouse Gas Emissions of Cities and Localized Rural Sources" (A44F, A57J, and A53E). There will be 35 talks including efforts in LA and 10 other cities.

Oct 29, 2013

  • We're busy with site visits and measurement campaigns in preparation for installing monitoring stations at Cal State Fullerton, USC, Compton, and San Clemente Island. Meanwhile initial data analysis and calibration system setup continue for some of the new operating stations (e.g., Granada Hills). Work is also progressing on the Hestia-LA high resolution CO2 emissions data set.

Aug 6, 2013

  • The new Total Column Carbon Observing Network (TCCON) site (previously at JPL) is now operating at NASA Dryden north of Los Angeles and a set of vertical profiles have been flown with the NASA DC-8. Nice work by Jim Podolske et al! We now have two TCCON sites for the LA megacity: one at Caltech within the urban core and one at the Dryden background site. The sites will also be important for urban and ex-urban observations by NASA's Orbiting Carbon Observatory (OCO-2).

July 17, 2013

  • Present your work at the AGU Fall Meeting in San Francisco Dec 2013! Session A042: Measuring and modeling the greenhouse gas emissions of cities and localized rural sources. There will be invited talks on the urban projects in LA, Indianpolis, and Paris and an update on field campaigns to address CH4 emissions from natural gas production. Abstract deadline is Aug 6, 2013. Abstract website For questions please contact the conveners: Riley Duren, Jocelyn Turnbull, Jim Butler, Irene Xueref-Remy.

July 6, 2013

  • The Granada Hills tower site has been installed and is undergoing checkout. Great work by the Earth Networks team!

May 10, 2013

  • The San Bernardino tower site has been installed and is undergoing checkout. Great progress by Marc Fischer, Ying Hsu, Sally Newman and their team. Meanwhile site surveys and instrument preparations continue towards installation at the Pomona, San Fernando Valley, south Los Angeles, Anaheim/Orange County, and San Clemente sites.

March 1, 2013

  • Please join us at our session at the 2013 AGU Meeting of the Americas: GC04. Measuring the carbon emissions of megacities on May 16 in Cancun, Mexico. Scientific program Representatives from the LA, Paris, Sao Paulo and Indianapolis teams will present talks. For questions please contact the conveners: Riley Duren, Kevin Gurney, and Paulo Artaxo.

Nov 20, 2012

  • Please join us at the upcoming AGU Fall Meeting in San Francisco on Friday, Dec 7 for sessions GC51B and GC53G: Monitoring the Greenhouse Gas Emissions of Cities and Localized Rural Sources Using Observations. See scientific program for list of talks, locations and times For questions please contact the conveners: Riley Duren, Jim Butler, Irene Xueref-Remy.

October 15, 2012

  • Congratulations to Chip Miller, Yuk Yung, Paul Wennberg and other members of the JPL and Caltech team for the recent selection of their technical development project "Developing Space-based Strategies to Monitor Megacity GHG Emissions". The activity is supported by the Keck Institute for Space Studies and will focus on the Los Angeles megacity. For more information see

October 1, 2012

  • Phase 1 of our Planetary Boundary Layer (PBL) campaign has been underway since the first week of August including remote-sensing instruments and in-situ sensing using rawinsondes. Please refer to our Intensive Campaigns page for more information.

August 8, 2012

  • Eric Kort's summer students at JPL recently completed the first phase of their NASA DEVELOP project "Greenhouse Gas Reduction Assessments by Current and Future NASA EOS"
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In the News

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Artist Concepts

Videos illustrating some of the key concepts for the Megacities Carbon Project.
megacities emmisions animation
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

Los Angeles Observational Network
Los Angeles Observational Network

This animation shows a perspective view of the Los Angeles basin looking north. Yellow columns represent continuous measurements of atmospheric carbon from commercial gas analyzers on radio towers and roof-tops. The California Laboratory for Atmospheric Remote Sensing (CLARS) on Mt Wilson uses reflected sunlight to track carbon across the basin.

Aircraft periodically sample the air coming in and out of the megacity domain. Satellites such as NASA's Orbiting Carbon Observatory-2 will sample the "urban domes" of carbon dioxide of Los Angeles and other megacities around the world. Animation courtesy: NASA's Goddard Space Flight Center, Conceptual Image Lab

California Laboratory for Atmospheric Remote Sensing
California Laboratory for Atmospheric Remote Sensing

One of the sites in the Megacities monitoring network for Los Angeles is the California Laboratory for Atmospheric Remote Sensing (CLARS) located on Mt Wilson. From an altitude of nearly 6000 ft, CLARS makes frequent scans during daylight hours across the LA basin. In this animation, the CLARS telescope mirror points sequentially to different pre-programmed points to sample sunlight scattering off the Earth's surface. The CLARS spectrometer splits the light from each reflection point into a spectrum (like colors in a rainbow) to reveal the unique "fingerprints" of carbon dioxide, methane and other gases in the atmosphere. The lines in the spectrum are due to absorption from the various gases - analysis of which is used to reveal the concentration of a given gas in a column of air for a given location. CLARS serves as a prototype for a future geostationary satellite instrument that may someday serve as a "carbon weather satellite" - providing frequent wall-to-wall mapping of greenhouse gases across entire cities and broader regions. Animation courtesy: NASA's Goddard Space Flight Center, Conceptual Image Lab

Megacities observing system for Los Angeles
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.

CO2 Simulations

Computer simulations illustrating the impact of emissions, meteorology and other factors on atmospheric CO2.

Concentrations of carbon dioxide (CO2) and other greenhouse gases in the atmosphere are constantly changing in response to surface sources and sinks that emit and remove carbon but equally important, in response to atmospheric circulation including the effect of winds and the vertical motion of the atmosphere that scientist call the planetary boundary layer. So interpreting measurements of concentrations of these gases and relating them to emissions requires careful treatment of atmospheric circulation. Scientist use models of the atmosphere both to predict atmospheric CO2 concentrations based on emission data sets (such as the Hestia-LA product) and/or to transform concentration measurements into flux estimates using a process called “inverse modeling”.

Examples of model outputs are shown here for 3 scales: urban, continental, and global.

Urban CO2 Simulation
Urban CO2 Simulation

The following video first shows fossil fuel CO2 emissions data at 1 km, hourly resolution for the LA Megacity from the Hestia project ( for 3 days in September 2011 (assuming linear scaling from 2002). The video then shows a model simulation that predicts the resulting enhancements (over background levels) of surface atmospheric CO2 concentrations for the same period at 1.3km, hourly resolution. Driven by JPL's Weather Research and Forecasting (WRF)-Greenhouse Gas (GHG)/Vegetation Photosynthesis and Respiration Model (VPRM) framework for Southern California. These products are preliminary, still undergoing validation and are intended strictly for educational purposes. Credit: Kevin Gurney (ASU); Sha Feng, Zhijin Li, Henry Kline, JPL.

Continental CO2 simulation
Continental CO2 simulation

Model simulation of surface atmospheric fossil fuel CO2 concentrations for the month of January 2010,with hourly time steps, and 0.5 degree x 0.625 degree (about 50x60) resolution. Assumes fossil fuel CO2 emissions are perfectly separated from the total CO2 fluxes. The color scale ranges from 400-480. Red indicates peak values of CO2, higher than 480 parts per mission (ppm). Concentrations smaller than the current global average (about 400 ppm) have been made transparent here to show the earth's surface. Driven by NASA's Carbon Monitoring System Flux framework. Credit: Richard Weidner, Meemong Lee, JPL.

Global CO2 Simulation
Global CO2 Simulation

Model simulation of surface atmospheric CO2 concentrations for the week of May 17-23, 2013,with hourly time steps, and 0.25 degree x 0.3125 degree (about 25km x 31 km) resolution. Driven by NASA's Carbon Monitoring System Flux framework. Credit: Richard Weidner, Meemong Lee, JPL.

High Resolution CO2 emissions data

Examples of high-resolution CO2 emissions data - illustrating the utility of space-time resolved data sets.
Hestia urban scale CO2 emissions data

Hestia ( combines extensive public database “data-mining” with traffic simulation and building-level energy-consumption modeling. Its high-resolution maps clearly identify CO2 emission sources. A preliminary version of the Hestia data set has been developed for the LA megacity and will be released shortly. Meanwhile the following images illustrate the utility of this data set.

Figures 1-3 courtesy Kevin Gurney, Risa Patarasuk, Yang Song (ASU). Figure 4 courtesy Preeti Rao (JPL).

Hestia coverage
Figure 1 This map shows the 5 counties of the Los Angeles megacity covered by the Hestia data set. Hestia classifies buildings by 3 major types: commercial, residential, and industrial. Each of these building types are further divided into sub-classes such as offices, retails, apartments, single family housing, apparel, wood products, etc.
Hestia classifications
Figure 2 Building classification for Hestia-LA at the parcel level for a small sample area in LA County. Commercial and residential buildings are divided into two age groups (pre-1980 and post-1979). Commercial buildings have a total of 22 classes (11 classes and 2 age groups). Residential buildings have a total of 8 classes (4 classes and 2 age groups). Industrial buildings have 21 classes and no age group separation. The industrial buildings were classified according to the NAICS (North American Industry Classification System).
Hestia emissions map
Figure 3 Preliminary estimate of CO2 emissions at the building footprint level in 2002 for a small area in LA County. For LA County, the building footprint data is available online. The carbon emissions are estimated based on the natural gas consumption, not electricity consumption (emissions from electricity generation are covered in separate power plants layer). The natural gas consumption values were derived from CBECS (Commercial Buildings Energy Consumption Survey and RECS (Residential Energy Consumption Survey) and data from the Vulcan Project . The results indicated that large offices, apartment complexes of 5 or more units, and industrial buildings tend to have the highest carbon emissions.
On road emissions map
Figure 4 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.

Satellite observations of LA

Examples of initial urban CO2 observations of Los Angeles from NASA's Orbiting Carbon Observatory.

One of the objectives of the Megacities Carbon Project is to test new scientific methods and technologies for tracking greenhouse gas emissions. One such emerging technology is offered by a new generation of satellites capable of measuring the carbon dioxide (CO2) emissions of cities from space. The following graphics illustrate how enhanced levels of CO2 in the atmosphere over Los Angeles are "seen" by NASA's Orbiting Carbon Observatory (OCO-2) (launched in July 2014).

Graphics courtesy: Henry Kline, Sha Feng, Zhijin Li, Annmarie Eldering, and John Howard (JPL).

surface co2 concentrations

The first image is a snapshot of patterns of surface CO2 concentrations over Los Angeles. The colors indicate the relative intensity of local CO2 compared to average background CO2 levels (about 400 parts per million or ppm, and rising). In this example, CO2 ranges from 3 ppm (purple) to nearly 30 ppm (lime) with the most intense levels over Pasadena. In reality the CO2 concentrations over LA are constantly changing in response to emissions and motion of the atmosphere (and can often exceed 70 ppm in different locations).

OCO-2: Normal Operations
OCO-2: Normal Operations

Since OCO-2 was designed to study the global carbon cycle it spends most of its time uniformly sampling the globe in either "nadir" or "glint" mode (learn more about OCO modes here). The following animation illustrates a single nadir-mode pass from OCO-2 over the Los Angeles basin - capturing a slice of the LA CO2 pattern. In this way OCO-2 will collect 8 footprints of data across the 10km wide swath, with orbit tracks that move east and west through the seasons.

OCO-2: Target Mode
OCO-2: Target Mode

The following animation illustrates the collection of 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.

OCO-2: Target Mode (cont.)
OCO-2: Target Mode (cont.)

This video illustrates how the spacecraft "wiggles" to perform Target mode observations (in this example, for the ground site at Lamont, Oklahoma).

OCO-3: City Mode
OCO-3: City Mode

OCO-3 is an instrument being assembled from spare parts from the OCO-2 mission and additional equipment for future deployment on the International Space Station (launch status: TBD). OCO-3 is intended to continue the OCO-2 CO2 data record for carbon cycle science but also has an additional capability enabled by a more flexible pointing system: City Mode. OCO-3 would allow regular sampling of more of the world's cities and power plants (over 80% of fossil-fuel CO2 emission sources every month) than available with OCO-2. OCO-3 would also provide broader mapping of each city's CO2 footprint as shown here for Los Angeles.

California Laboratory for Atmospheric Remote Sensing

Examples of greenhouse gas data from the CLARS remote sensing instrument on Mt Wilson.

A ground-based remote sensing instrument located at the California Laboratory for Atmospheric Remote Sensing (CLARS) on Mount Wilson has been mapping CO2, CH4 and other important trace gases across the Los Angeles megacity since 2010. The figures below show how column-averaged concentrations of CO2 vary across the LA basin in both space and time. Both figures show data collected on May 29, 2010 (left: 8:30 am, right: 1:30 pm). The combined effects of atmospheric motion (particularly the peak growth of the planetary boundary layer around midday) and localized emissions account for the observed transition between the relatively "flat" distribution seen in the morning compared to the strong gradient in the afternoon. The goals of CLARS are to derive high spatio-temporal top-down greenhouse gas emissions in the megacity, and to serve as a testbed for a potential future geostationary satellite mission (the Global Carbon Process Investigation). Courtesy: Stanley P. Sander (stanley.p.sander at and Clare Wong (clare.wong at See our publications page for papers on CLARS by Wong et al (2014) and Fu et al (2014).

Timelapse video of LA

Examples of LA's "urban metabolism".
USC Downtown LA timelapse

This time-lapse video was created from hourly snapshots from a webcam at our monitoring site at USC. Looking north towards the downtown LA skyline we can watch a “month in the life” (August 2014) – illustrating the daily ebb and flow of a small but important cross-section of the LA megacity. With Mount Wilson and the San Gabriels as a backdrop we can experience the range of atmospheric conditions that prevail in LA such as the evening marine layer and development of the midday inversion layer that traps polluted air including visible aerosols and invisible greenhouse gases. We can also see evidence of cycles of human activity including traffic on the 10 freeway at the base of the skyscrapers and the use of nightlights. We even catch the demolition of a small building around August 20 (watch carefully, it happens fast). Even heavily built-up cities like LA exhibit behavior that some scientists liken to the “metabolism” of a huge organism.