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| Titel |
Sensitivity of WRF cloud microphysics to simulations of a severe thunderstorm event over Southeast India |
| VerfasserIn |
M. Rajeevan, A. Kesarkar, S. B. Thampi, T. N. Rao, B. Radhakrishna, M. Rajasekhar |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 28, no. 2 ; Nr. 28, no. 2 (2010-02-19), S.603-619 |
| Datensatznummer |
250016788
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| Publikation (Nr.) |
 copernicus.org/angeo-28-603-2010.pdf |
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| Zusammenfassung |
In the present study, we have used the Weather Research and Forecasting
(WRF) model to simulate the features associated with a severe thunderstorm
observed over Gadanki (13.5° N, 79.2° E), over southeast India, on
21 May 2008 and examined its sensitivity to four different microphysical
(MP) schemes (Thompson, Lin, WSM6 and Morrison). We have used the WRF model
with three nested domains with the innermost domain of 2 km grid spacing
with explicit convection. The model was integrated for 36 h with the GFS
initial conditions of 00:00 UTC, 21 May 2008. For validating simulated features
of the thunderstorm, we have considered the vertical wind measurements made
by the Indian MST radar installed at Gadanki, reflectivity profiles by the
Doppler Weather Radar at Chennai, and automatic weather station data at
Gadanki.
There are major differences in the simulations of the thunderstorm among the
MP schemes, in spite of using the same initial and boundary conditions and
model configuration. First of all, all the four schemes simulated severe
convection over Gadanki almost an hour before the observed storm. The DWR
data suggested passage of two convective cores over Gadanki on 21 May, which
was simulated by the model in all the four MP schemes. Comparatively, the
Thompson scheme simulated the observed features of the updraft/downdraft
cores reasonably well. However, all the four schemes underestimated strength
and vertical extend of the updraft cores. The MP schemes also showed
problems in simulating the downdrafts associated with the storm. While the
Thompson scheme simulated surface rainfall distribution closer to
observations, the other three schemes overestimated observed rainfall.
However, all the four MP schemes simulated the surface wind variations
associated with the thunderstorm reasonably well. The model simulated
reflectivity profiles were consistent with the observed reflectivity
profile, showing two convective cores. These features are consistent with
the simulated condensate profiles, which peaked around 5–6 km. As the
results are dependent on initial conditions, in simulations with different
initial conditions, different schemes may become closer to observations. The
present study suggests not only large sensitivity but also variability of
the microphysical schemes in the simulations of the thunderstorm. The study
also emphasizes the need for a comprehensive observational campaign using
multi-observational platforms to improve the parameterization of the cloud
microphysics and land surface processes over the Indian region. |
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