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| Titel |
Effects of assimilating precipitation zones derived from satellite and lightning data on numerical simulations of tropical-like Mediterranean storms |
| VerfasserIn |
L. Fita, R. Romero, A. Luque, C. Ramis |
| 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 ; 27, no. 8 ; Nr. 27, no. 8 (2009-08-26), S.3297-3319 |
| Datensatznummer |
250016632
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| Publikation (Nr.) |
 copernicus.org/angeo-27-3297-2009.pdf |
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| Zusammenfassung |
| The scarcity of meteorological observations in maritime areas is a
well-known problem that can be an important limitation in the study
of different phenomena. Tropical-like storms or medicanes developed
over the Mediterranean sea are intense storms with some similarities
to the tropical ones. Although they do not reach the hurricane
intensity, their potential for damage is very high, due to the
densely populated Mediterranean coastal regions. In this study, the
two notable cases of medicane development which occurred in the
western Mediterranean basin in September 1996 and October 2003, are
considered. The capability of mesoscale numerical models to simulate
general aspects of such a phenomena has been previously shown. With
the aim of improving the numerical results, an adjustment of the
humidity vertical profiles in MM5 simulations is performed by means
of satellite derived precipitation. Convective and stratiform
precipitation types obtained from satellite images are used to
individually adjust the profiles. Lightning hits are employed to
identify convective grid points. The adjustment of the vertical
humidity profiles is carried out in the European Centre for
Medium-Range Weather Forecasts (ECMWF) analyses used as initial
conditions for the simulations. Analyses nudging to ECMWF analyses
and to the satellite-based humidity-corrected version of these
analyses has also been applied using Four Dimensional Data
Assimilation (FDDA). An additional adjustment is applied as
observation nudging of satellite/lightning information at different
time and spatial resolutions. Statistical parameters are proposed
and tested as an objective way to intercompare satellite-derived and
simulated trajectories. Simulations of medicanes exhibit a strong
sensitivity to vertical humidity profiles. Trajectories of the
storms are improved or worsened by using FDDA. A case dependence is
obtained on the characteristics of the humidity-corrected medicanes.
FDDA sensitivity on temporal and spatial resolution of the
assimilated data also presents a case dependence. It also shows a
significant sensitivity of the results of the observation nudging to
the specific choice of the values of coefficient weight and vertical
ratio of the ingested observations. |
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