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| Titel |
Intensity-dependent parameterization of elevation effects in precipitation analysis |
| VerfasserIn |
T. Haiden, G. Pistotnik |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: Observation, Prediction and Verification of Precipitation (EGU Session 2008) ; Nr. 20 (2009-03-16), S.33-38 |
| Datensatznummer |
250014332
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| Publikation (Nr.) |
 copernicus.org/adgeo-20-33-2009.pdf |
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| Zusammenfassung |
| Elevation effects in long-term (monthly to inter-annual)
precipitation data have been widely studied and are taken into account in
the regionalization of point-like precipitation amounts by using methods
like external drift kriging and cokriging. On the daily or hourly time
scale, precipitation-elevation gradients are more variable, and difficult to
parameterize. For example, application of the annual relative
precipitation-elevation gradient to each 12-h sub-period reproduces the
annual total, but at the cost of a large root-mean-square error. If the
precipitation-elevation gradient is parameterized as a function of
precipitation rate, the error can be substantially reduced. It is shown that
the form of the parameterization suggested by the observations conforms to
what one would expect based on the physics of the orographic precipitation
process (the seeder-feeder mechanism). At low precipitation rates,
orographic precipitation is "conversion-limited", thus increasing roughly
linearly with precipitation rate. At higher rates, orographic precipitation
becomes "condensation-limited" thus leading to an additive rather than
multiplicative orographic precipitation enhancement. Also it is found that
for large elevation differences it becomes increasingly important to take
into account those events where the mountain station receives precipitation
but the valley station remains dry. |
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