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| Titel |
NOx emission fluxes estimated from OMI-retrieved tropospheric NO2 columns over East Asia |
| VerfasserIn |
Kyung M. Han, Chul H. Song |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147541
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| Publikation (Nr.) |
 EGU/EGU2017-11719.pdf |
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| Zusammenfassung |
| In this study, we estimated top-down NOx emissions over East Asia, using available information on the levels of NO2 and NOx, wind vectors, and geolocation from OMI observation and CAMQ/WRF simulations. For the high-resolved (i.e., 30 km×30 km) top-down NOx emissions, an algorithm was developed based on the mass balance equation. Two main parameters were incorporated in the algorithm. For the first, atmospheric NOx molecules transported from/to the adjacent cells for considering the non-local sources were sophisticatedly calculated. For the second, effective NOx lifetime for the nonlinearity between NO2 columns and NOx emissions was estimated from the mass balance equation. In the analysis, the NOx transports from/to the neighborhood cells had significant impacts on the effective NOx lifetime in both cold and warm seasons. Also, in the sensitivity test, we showed that the errors in the top-down NOx estimations can be reduced by filtering the data whose NOx lifetimes are smaller than 5 hours. The relative errors caused by the uncertain issues of NOx lifetimes with interpolation of satellite data were ~13% and ~5% in January and July, 2014. Using the algorithm, the top-down NOx emissions were estimated to be 1.04 and 1.18 Tg N/month over our entire domain for January and July, respectively. The values corresponded to decreases by ~15% and ~2%, compared with the bottom-up NOx emissions in January and July, respectively. We also compared the CMAQ-estimated NO2 columns with OMI-retrieved NO2 columns to evaluate the bottom-up NOx emission and investigate how much the top-down NOx emissions estimated from our algorithm were improved. |
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