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| Titel |
Ensemble data assimilation of total column ozone using a coupled meteorology–chemistry model and its impact on the structure of Typhoon Nabi (2005) |
| VerfasserIn |
S. Lim, S. K. Park, M. Zupanski |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 17 ; Nr. 15, no. 17 (2015-09-08), S.10019-10031 |
| Datensatznummer |
250120020
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| Publikation (Nr.) |
 copernicus.org/acp-15-10019-2015.pdf |
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| Zusammenfassung |
| Ozone (O3) plays an important role in chemical reactions and is usually
incorporated in chemical data assimilation (DA). In tropical cyclones (TCs),
O3 usually shows a lower concentration inside the eyewall and an
elevated concentration around the eye, impacting meteorological as well as
chemical variables. To identify the impact of O3 observations on TC
structure, including meteorological and chemical information, we developed a
coupled meteorology–chemistry DA system by employing the Weather Research and
Forecasting model coupled with Chemistry (WRF-Chem) and an ensemble-based DA
algorithm – the maximum likelihood ensemble filter (MLEF). For a TC case
that occurred over East Asia, Typhoon Nabi (2005), our results indicate that
the ensemble forecast is reasonable, accompanied with larger background state
uncertainty over the TC, and also over eastern China. Similarly, the
assimilation of O3 observations impacts meteorological and chemical
variables near the TC and over eastern China. The strongest impact on air
quality in the lower troposphere was over China, likely due to the pollution
advection. In the vicinity of the TC, however, the strongest impact on
chemical variables adjustment was at higher levels. The impact on
meteorological variables was similar in both over China and near the TC. The
analysis results are verified using several measures that include the cost
function, root mean square (RMS) error with respect to observations, and
degrees of freedom for signal (DFS). All measures indicate a positive impact
of DA on the analysis – the cost function and RMS error have decreased by
16.9 and 8.87 %, respectively. In particular, the DFS indicates a strong
positive impact of observations in the TC area, with a weaker maximum over
northeastern China. |
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