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| Titel |
Diurnal cycle of monsoon rainstorms in complex terrain from spaceborne and surface-based radar |
| VerfasserIn |
C. L. Wall, E. Zipser |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250029672
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| Zusammenfassung |
| We make use of 10 years of data from the TRMM precipitation feature database to extract the diurnal cycle of
rainfall over the complex terrain of the southwestern United States during the summer monsoon rainy season
of July and August. This limited region in Arizona and New Mexico is chosen partly because there are data
available from the 10-cm operational WSR-88D radars operated by the National Weather Service, but there are
strong similarities between this region and the Sierra Madre Occidental of Mexico studied intensively during the
NAME field program in 2004. Both regions are subject to occasional destructive flash flooding, and we are
interested in the differences between "ordinary" and extreme events. The surface-based and satellite-based rainfall
estimates are complementary, the former used to study the life cycle of specific events (but with data gaps from
beam blockage by terrain), the latter not restricted geographically but temporally. We demonstrate that the diurnal
cycle on most days is dominated by frequent small storms, which start before noon on the highest terrain and
propagate to lower elevations during the afternoon, occasionally (but importantly) continuing to the low deserts.
Events that are both large and intense occur most frequently in late afternoon. The small storms that develop
early produce relatively little of the region's precipitation when compared to rainfall events that cover a large area
(but lack intense convection). These rainy features have a markedly different diurnal cycle, with a maximum
frequency of occurrence in the evening. |
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