Climate change: Track urban emissions on a human scale

Gurney, K. R.; Romero-Lankao, Paty; Seto, Karen C.; Hutyra, Lucy R.; Duren, Riley; Kennedy, Christopher; Grimm, Nancy B.; Ehleringer, James R.; Marcotullio, Peter J.; Hughes, Sara; Pincetl, Stéphanie; Chester, Mikhail; Runfola, Daniel Miller; Feddema, Johannes J.; Sperling, Joshua

doi:10.1038/525179a

Cited by 169 publications

(112 citation statements)

References 7 publications

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“…Therefore, we used the statistical CO 2 data at Mauna Loa by NOAA as the background CO2 levels to compare with the statistical values of satellites. In addition, we analyzed the difference in XCO 2 variation trend between GOSAT and OCO-2 combined with land use types provided by ISLSCP II MODIS (Collection 4) IGBP Land Cover, 2000-2001 [58]. …”

Section: Methodsmentioning

confidence: 99%

Comparison of Satellite-Observed XCO2 from GOSAT, OCO-2, and Ground-Based TCCON

et al. 2017

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CO 2 is one of the most important greenhouse gases. Its concentration and distribution in the atmosphere have always been important in studying the carbon cycle and the greenhouse effect. This study is the first to validate the XCO 2 of satellite observations with total carbon column observing network (TCCON) data and to compare the global XCO 2 distribution for the passive satellites Orbiting Carbon Observatory-2 (OCO-2) and Greenhouse Gases Observing Satellite (GOSAT), which are on-orbit greenhouse gas satellites. Results show that since GOSAT was launched in 2009, its mean measurement accuracy was −0.4107 ppm with an error standard deviation of 2.216 ppm since 2009, and has since decreased to −0.62 ppm with an error standard deviation of 2.3 ppm during the past two more years (2014)(2015)(2016), while the mean measurement accuracy of the OCO-2 was 0.2671 ppm with an error standard deviation of 1.56 ppm from September 2014 to December 2016. GOSAT observations have recently decreased and lagged behind OCO-2 on the ability to monitor the global distribution and monthly detection of XCO 2 . Furthermore, the XCO 2 values gathered by OCO-2 are higher by an average of 1.765 ppm than those by GOSAT. Comparison of the latitude gradient characteristics, seasonal fluctuation amplitude, and annual growth trend of the monthly mean XCO 2 distribution also showed differences in values but similar line shapes between OCO-2 and GOSAT. When compared with the NOAA statistics, both satellites' measurements reflect the growth trend of the global XCO 2 at a low and smooth level, and reflect the seasonal fluctuation with an absolutely different line shape.

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Section: Methodsmentioning

confidence: 99%

Comparison of Satellite-Observed XCO2 from GOSAT, OCO-2, and Ground-Based TCCON

et al. 2017

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“…The temporal variations are driven by a combination of modelled activity (building energy modelling) and monitoring (power plant emissions) (Gurney et al, 2009). Hestia-LA, by contrast, is a fossil fuel CO 2 emissions data product specific in space and time to the individual building, road segments, and point sources covering the Los Angeles megacity domain for the years of 2011 and 2012 Gurney et al, 2015Gurney et al, , 2012Zhou and Gurney, 2010). It quantifies hourly FFCO 2 emissions for the counties of Los Angeles, Orange, San Bernardino,…”

Section: Configuration For the Co 2 Simulationmentioning

confidence: 99%

“…Anthropogenic FFCO 2 fluxes were alternatively prescribed from the Vulcan 2.2 and Hestia-LA 1.0 FFCO 2 emission products developed at Arizona State University (Gurney et al, 2009(Gurney et al, , 2012(Gurney et al, , 2015Rao et al, 2016). Both emission products were developed using "bottom-up" methods.…”

Section: Configuration For the Co 2 Simulationmentioning

confidence: 99%

Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO<sub>2</sub> emissions

et al. 2016

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Abstract. Megacities are major sources of anthropogenic fossil fuel CO 2 (FFCO 2 ) emissions. The spatial extents of these large urban systems cover areas of 10 000 km 2 or more with complex topography and changing landscapes. We present a high-resolution land-atmosphere modelling system for urban CO 2 emissions over the Los Angeles (LA) megacity area. The Weather Research and Forecasting (WRF)-Chem model was coupled to a very high-resolution FFCO 2 emission product, Hestia-LA, to simulate atmospheric CO 2 concentrations across the LA megacity at spatial resolutions as fine as ∼ 1 km. We evaluated multiple WRF configurations, selecting one that minimized errors in wind speed, wind direction, and boundary layer height as evaluated by its performance against meteorological data collected during the CalNex-LA campaign (May-June 2010). Our results show no significant difference between moderate-resolution (4 km) and high-resolution (1.3 km) simulations when evaluated against surface meteorological data, but the highresolution configurations better resolved planetary boundary layer heights and vertical gradients in the horizontal mean winds. We coupled our WRF configuration with the Vulcan 2.2 (10 km resolution) and Hestia-LA (1.3 km resolution) fossil fuel CO 2 emission products to evaluate the impact of the spatial resolution of the CO 2 emission products and the meteorological transport model on the representation of spatiotemporal variability in simulated atmospheric CO 2 concentrations. We find that high spatial resolution in the fossil fuel CO 2 emissions is more important than in the atmospheric model to capture CO 2 concentration variability across the LA megacity. Finally, we present a novel approach that employs simultaneous correlations of the simulated atmospheric CO 2 fields to qualitatively evaluate the greenhouse gas measurement network over the LA megacity. Spatial correlations in the atmospheric CO 2 fields reflect the coverage of individual measurement sites when a statistically significant number of sites observe emissions from a specific source or location. We conclude that elevated atmospheric CO 2 concentrations over the LA megacity are composed of multiple fine-scale plumes rather than a single homogenous urban dome. Furthermore, we conclude that FFCO 2 emissions monitoring in the LA megacity requires FFCO 2 emissions modelling with ∼ 1 km resolution becausePublished by Copernicus Publications on behalf of the European Geosciences Union. 9020 S. Feng et al.: LA megacity GHG modelling system coarser-resolution emissions modelling tends to overestimate the observational constraints on the emissions estimates.

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“…Cities and their surrounding urban regions occupy less than 3 % of the global land surface (Grimm et al, 2008) but are home to 54 % of the world population (WHO, 2014) and account for more than 70 % of global fossil-fuel CO 2 emissions (Gurney et al, 2015). Hence, accurate methods for measuring urban-and regional-scale carbon fluxes are required in order to design and implement policies for emission reduction initiatives.…”

Section: Introductionmentioning

confidence: 99%

Differential column measurements using compact solar-tracking spectrometers

et al. 2016

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Abstract. We demonstrate the use of compact solar-tracking Fourier transform spectrometers (Bruker EM27/SUN) for differential measurements of the column-averaged dry-air mole fractions of CH 4 and CO 2 within urban areas. Using Allan variance analysis, we show that the differential column measurement has a precision of 0.01 % for X CO 2 and X CH 4 with an optimum integration time of 10 min, corresponding to Allan deviations of 0.04 ppm and 0.2 ppb, respectively. The sensor system is very stable over time and after relocation across the continent. We report tests of the differential column measurement, and its sensitivity to emission sources, by measuring the downwind-minus-upwind column difference X CH 4 across dairy farms in the Chino area, California, and using the data to verify emissions reported in the literature. Ratios of spatial column differences X CH 4 / X CO 2 were observed across Pasadena within the Los Angeles basin, indicating values consistent with regional emission ratios from the literature. Our precise, rapid measurements allow us to determine significant short-term variations (5-10 min) of X CO 2 and X CH 4 and to show that they represent atmospheric phenomena.Overall, this study helps establish a range of new applications for compact solar-viewing Fourier transform spectrometers. By accurately measuring the small differences in integrated column amounts across local and regional sources, we directly observe the mass loading of the atmosphere due to the influence of emissions in the intervening locale. The inference of the source strength is much more direct than inversion modeling using only surface concentrations and less subject to errors associated with small-scale transport phenomena.

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Climate change: Track urban emissions on a human scale

Cited by 169 publications

References 7 publications

Comparison of Satellite-Observed XCO2 from GOSAT, OCO-2, and Ground-Based TCCON

Comparison of Satellite-Observed XCO2 from GOSAT, OCO-2, and Ground-Based TCCON

Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO<sub>2</sub> emissions

Differential column measurements using compact solar-tracking spectrometers

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Climate change: Track urban emissions on a human scale

Cited by 169 publications

References 7 publications

Comparison of Satellite-Observed XCO2 from GOSAT, OCO-2, and Ground-Based TCCON

Comparison of Satellite-Observed XCO2 from GOSAT, OCO-2, and Ground-Based TCCON

Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO&lt;sub&gt;2&lt;/sub&gt; emissions

Differential column measurements using compact solar-tracking spectrometers

Contact Info

Product

Resources

About

Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO<sub>2</sub> emissions