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| Titel |
NOx emissions in China constrained by satellite observations: a new inversion approach |
| VerfasserIn |
Bas Mijling, Ronald van der A |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048154
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| Zusammenfassung |
| In the past 30 years China’s economy showed an average growth rate of 10%, not only
bringing more material wealth to its 1,300 million inhabitants, but also generating
unprecedented air pollution. Because ground measurements of air quality in China are often
inaccessible, satellite observations are an obvious tool to monitor country-wide pollution
levels.
Observations of tropospheric NO2 by the sun-synchronized polar-orbiting instruments
OMI and GOME-2 have almost daily global coverage. To relate these observations to NOx
emissions, we implemented the regional chemical transport model CHIMERE for the Eastern
Chinese domain at a 0.25 degree resolution. Differences between simulated and observed
concentrations provides information on how to adjust the emission inventory. The key
to solve this inversion problem is finding the spatial relationship between NO2
concentrations and NOx emissions. We will present a new approach for approximating these
sensitivities, without the use of adjoint model code or ensemble techniques. The
chemical transport model is treated as a black box, which eases implementation of data
assimilation applications based on other models or other model domains. Our method is
designed to perform daily top-down emission estimates of short-lived species (such as
NOx) for all grid cells (15,000) in the model domain. It takes the transport of the
trace gas over the grid into account using a simplified, two-dimensional transport
scheme.
The calculation of the sensitivities is fast compared to other techniques, thus enabling
emission estimates from satellite observations on a daily basis. We will present some first
results using OMI and GOME-2 observations over East-China. Future research will
concentrate on updating the Chinese NOx emissions operationally, which will improve air
quality forecasts for China, and constructing a long time series, which will give
insight in the evolution of air quality and the effectiveness of air quality measures. |
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