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| Titel |
High-resolution numerical modeling of mesoscale island wakes and sensitivity to static topographic relief data |
| VerfasserIn |
C. G. Nunalee, Á. Horváth, S. Basu |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 8, no. 8 ; Nr. 8, no. 8 (2015-08-26), S.2645-2653 |
| Datensatznummer |
250116511
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| Publikation (Nr.) |
 copernicus.org/gmd-8-2645-2015.pdf |
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| Zusammenfassung |
| Recent decades have witnessed a drastic increase in the fidelity of numerical weather prediction (NWP) modeling. Currently, both
research-grade and operational NWP models regularly perform simulations with horizontal grid spacings as fine as 1 km. This
migration towards higher resolution potentially improves NWP model solutions by increasing the resolvability of mesoscale
processes and reducing dependency on empirical physics parameterizations. However, at the same time, the accuracy of
high-resolution simulations, particularly in the atmospheric boundary layer (ABL), is also sensitive to orographic forcing which can
have significant variability on the same spatial scale as, or smaller than, NWP model grids. Despite this sensitivity, many
high-resolution atmospheric simulations do not consider uncertainty with respect to selection of static terrain height data set. In
this paper, we use the Weather Research and Forecasting (WRF) model to simulate realistic cases of lower tropospheric flow over
and downstream of mountainous islands using the default global 30 s United States Geographic Survey terrain height data set
(GTOPO30), the Shuttle Radar Topography Mission (SRTM), and the Global Multi-resolution Terrain Elevation Data set (GMTED2010)
terrain height data sets. While the differences between the SRTM-based and GMTED2010-based simulations are extremely small, the GTOPO30-based simulations differ significantly. Our results demonstrate cases where the
differences between the source terrain data sets are significant enough to produce entirely different
orographic wake mechanics, such as vortex shedding vs. no vortex shedding. These results are also compared to MODIS visible
satellite imagery and ASCAT near-surface wind retrievals. Collectively, these results highlight the importance of utilizing accurate static orographic boundary conditions when running high-resolution mesoscale models. |
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