Verifying Greenhouse Gas Emissions Methods to Support International Climate Agreements (2010) / Chapter Skim
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4 Emissions Estimated from Atmospheric and Oceanic Measurements
4 Emissions Estimated from Atmospheric and Oceanic Measurements
Pages 53-70
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From page 53... ...
, methane (CH4) , and N2O all have large and ing combines atmospheric and oceanic measurements uncertain natural sources and sinks that obscure the with a model for atmospheric transport and mixing signals from anthropogenic emissions.
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From page 54... ...
may be able to constrain large emissions at a subGREENHOUSE GAS EMISSIONS national level (e.g., rice paddies in India and Southeast Tracer-transport inversion methods have been Asia) , but this has not yet been verified using a multiused to estimate emissions of CO2, CH4, N2O, and model approach with realistic errors on the satellite data hydrofluorocarbons (HFCs)
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From page 55... ...
. The approach measurements would significantly aid in verification obviates the need for accurate tracer-transport model- or falsification of reported national emissions if the ing and can define the relative emissions in a polluted pattern of emissions being tested is provided and the air sample to 10 percent or better.
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From page 56... ...
. The spread compared emissions estimates from different tracerin north-south transport among the different models, transport models and found that year-to-year differwhile nonnegligible, is not large enough to invalidate ences in estimates for different regions within the same interpretations of annual mean CO2 emissions from latitude zone were surprisingly consistent between broad latitude bands.
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From page 57... ...
The reason for Because of transport uncertainty and the lack of the difference is the large interannual variation in the measurements over much of the globe, estimates of size of sources and sinks in the terrestrial biosphere and the total net flux of CO2 from broad bands of latitude oceans, which must be separated from the total atmo- on a seasonal time scale are uncertain by at best 25spheric increase to estimate the contribution from fossil 49 percent, compared to only 7 percent for the globe fuel. Uncertainty in the anthropogenic emissions from (Table 4.1)
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From page 58... ...
that anthropogenic emissions increase the abundance of CO2 by, on average, a fraction of a part per million Verification of CFCs, HFCs, and Other Synthetic (ppm) in the whole column (ranging from 0.06 ppm Greenhouse Gas Emissions for Australia to 0.76 ppm for the United States)
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From page 59... ...
Measurements of Large Emission Sources spheric inverse modeling can provide a strict test of the global sum of national greenhouse gas emissions A large fraction of fossil-fuel emissions emanates inventories on an annual basis, but it has not been able from large local sources, such as cities or power plants, to identify the countries whose emissions are in error. and thus the effect of national mitigation measures should be evident in the "domes" of CO2 that they NEW APPROACHES FOR INCREASING THE produce (Idso et al., 2001; Pataki et al., 2003; Rigby et ACCURACY OF NATIONAL EMISSIONS al., 2008a)
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From page 60... ...
The variability of CO2 and other 30 ppm, depending on proximity to local sources and greenhouse gases in cities is substantially greater than atmospheric mixing (see Riley et al., 2008; Mays et that measured at clean air marine boundary layer al., 2009; and the analysis of signals from urban areas, stations. Effective sampling of this variability in and TABLE 4.3 CO2 Emissions for Selected Cities Emissions Area Population Total Commerce + industry Residential Utilities Transportation City (km2)
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From page 61... ...
By characterizing urban to suburban gradients, it may be possible to detect relative changes in fossil fuel emissions over time. The 14CO2 measurements of annual plants using accelerator mass spectrometry are FIGURE 4.4 Instantaneous mole fraction of atmospheric CO2 at the surface (top)
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From page 62... ...
regional atmospheric modeling to a large region are not available. Second, whereas the help design the local network and to quantify variability concentration anomaly over a city or power plant has an from seasonally and interannually varying winds, and unambiguous origin, transport errors make attribution (3)
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From page 63... ...
Simul- of 1-2 ppm and significantly larger than the groundtaneous creation of detailed bottom-up inventories of tested value of 1 ppm. In contrast, because a GOSAT emissions for these same representative areas would sample covers a larger area than an OCO sample, the facilitate transport modeling and enable the efficacy of CO2 perturbation within a GOSAT sample would be different atmospheric approaches for trend detection approximately 0.1 percent (~0.4 ppm)
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From page 64... ...
. capability of OCO, together with a program of surface Accelerator mass spectrometry can measure 14C in and aircraft sampling in and around large local sources CO2 in only 2 liters of ambient air to a precision of would address all four main problems associated with 0.2 percent.
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From page 65... ...
. The 84 virtual sampling locations, where virtual 14CO2 measurements were made every 3 days at 14:00 local time, are plotted as "pluses." Right panel: Uncertainty of the total estimated flux in each 5 × 5 degree area. For both panels, January emissions and uncertainties are shown, but those for other months are not substantially different. SOURCE: Courtesy of John Miller, NOAA/ESRL. Measurement Programs to Reduce Model Errors estimates of the global fossil-fuel flux that would be accurate enough to check trends from self-reported To improve estimates of national anthropogenic inventories collectively (Table 4.1)
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From page 66... ...
assimilation systems employ 3-hourly or 6-hourly Expansion of the GAW network in the vertical atmospheric circulation statistics from a reanalysis. dimension would allow more meaningful comparisons Carbon data assimilation combines, in principle, with satellite retrievals of column-averaged CO2 than emissions inventories and data on land use, greenhouse ground-based measurements alone and would also pro- gas abundances, and meteorology with models of the vide a routine experimental check on how models trans- atmosphere, ecosystems, and oceans into a coherent port emissions from the boundary layer to the free troposphere.
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From page 67... ...
The output of the improved GFED2 model. model is then used as input to an atmospheric transport The most sophisticated carbon data assimilation
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From page 68... ...
using a carbon-climate model, so that other land use and the significant portion of fossil-fuel uncertainties in the air flow and transport estimates emissions from countries that are produced by large are propagated to the trace gas variables, and the trace local sources. They would also greatly improve our gas data inform the meteorological state, especially in capacity to estimate total fossil-fuel emissions from regions with few wind observations.
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From page 69... ...
, gas emissions. Expanding the network to increase col- NOAA, NASA, and the Department of Energy should lection of vertical profiles of greenhouse gases would expand campaigns to sample the time evolution of constrain atmospheric transport and facilitate inter- tracer fields at high resolution as well as studies that pretation of satellite data.
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From page 70... ...
-- augbecome integral components of emission estimation mented with high-precision, high-accuracy CO 2 from a replacement OCO. sampling for bottom-up and top-down model calibra • Sustain the infrastructure to measure natural tion -- and continued measurements of the oceanic sink sources and sinks on land and in the ocean, which (see Appendix C)
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