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| Titel |
Comparison of the diurnal variations of warm-season precipitation for East Asia vs. North America downstream of the Tibetan Plateau vs. the Rocky Mountains |
| VerfasserIn |
Yuanchun Zhang, Fuqing Zhang, Jianhua Sun |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 19 ; Nr. 14, no. 19 (2014-10-13), S.10741-10759 |
| Datensatznummer |
250119095
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| Publikation (Nr.) |
 copernicus.org/acp-14-10741-2014.pdf |
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| Zusammenfassung |
| A wave-number-frequency spectral decomposition technique is used to analyze
the high-resolution NOAA/Climate Prediction Center morphing technique
(CMORPH) precipitation data set and to explore the differences and
similarities of the diurnal variation of warm-season precipitation in the
East Asia and North America downstream of big topography. The predominant
phase speed of precipitation at different time scales for North America,
averaged over all warm-season months (May–August) for 2003–2010, is
~20 ms−1, which is faster than the speed of
~14 ms−1 calculated for East Asia. Consistent with the
recent studies of the precipitation diurnal cycles for these two regions,
the difference in the diurnal phase propagation is likely due to the
difference in the mean steering level wind speed for these two regions. The
wave-number-frequency spectral analysis further reveals the complex,
multi-scale, multi-modal nature of the warm-season precipitation variation
embedded within the diurnal cycle over both continents, with phase speeds
varying from 10 to 30 ms−1 and wave periods varying from diurnal to a
few hours. At the diurnal frequency regulated by the thermodynamically
driven mountains–plains solenoids (MPSs), increased precipitation for both
continents first originates in the afternoon from the eastern edge of big
topography and subsequently moves downslope in the evening and reaches the
broad plains area at night. More complex diurnal evolutions are observed in
East Asia due to the more complex, multistep terrains east of the Tibetan
Plateau and the associated localized MPS circulations. Nevertheless,
increased variation of precipitation at smaller spatial and temporal scales
is evident in the active phase of the dominant diurnal cycle for both
continents. |
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