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Titel |
Short period forecasting of catchment-scale precipitation. Part I: the role of Numerical Weather Prediction |
VerfasserIn |
M. A. Pedder, M. Haile, A. J. Thorpe |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 4, no. 4 ; Nr. 4, no. 4, S.627-633 |
Datensatznummer |
250001884
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Publikation (Nr.) |
copernicus.org/hess-4-627-2000.pdf |
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Zusammenfassung |
A deterministic forecast of
surface precipitation involves solving a time-dependent moisture balance
equation satisfying conservation of total water substance. A realistic solution
needs to take into account feedback between atmospheric dynamics and the
diabatic sources of heat energy associated with phase changes, as well as
complex microphysical processes controlling the conversion between cloud water
(or ice) and precipitation. Such processes are taken into account either
explicitly or via physical parameterisation schemes in many operational
numerical weather prediction models; these can therefore generate precipitation
forecasts which are fully consistent with the predicted evolution of the
atmospheric state as measured by observations of temperature, wind, pressure and
humidity.
This paper reviews briefly the atmospheric moisture balance equation and how it may
be solved in practice. Solutions are obtained using the Meteorological Office
Mesoscale version of its operational Unified Numerical Weather Prediction (NWP)
model; they verify predicted precipitation rates against catchment-scale values
based on observations collected during an Intensive Observation Period (IOP) of
HYREX. Results highlight some limitations of an operational NWP forecast in
providing adequate time and space resolution, and its sensitivity to initial
conditions. The large-scale model forecast can, nevertheless, provide important
information about the moist dynamical environment which could be incorporated
usefully into a higher resolution, ‘storm-resolving’ prediction scheme.
Keywords: Precipitation forecasting; moisture budget; numerical weather prediction |
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