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| Titel |
Soil moisture–precipitation coupling: observations from the Oklahoma Mesonet and underlying physical mechanisms |
| VerfasserIn |
T. W. Ford, A. D. Rapp, S. M. Quiring, J. Blake |
| 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 ; 19, no. 8 ; Nr. 19, no. 8 (2015-08-21), S.3617-3631 |
| Datensatznummer |
250120793
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| Publikation (Nr.) |
 copernicus.org/hess-19-3617-2015.pdf |
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| Zusammenfassung |
| Interactions between soil moisture and the atmosphere are driven by the
partitioning of sensible and latent heating, through which soil moisture
has been connected to atmospheric modifications that could potentially lead
to the initiation of convective precipitation. The majority of previous studies
linking the land surface to subsequent precipitation have used atmospheric
reanalysis or model data sets. In this study, we link in situ observations of soil
moisture from more than 100 stations in Oklahoma to subsequent unorganized
afternoon convective precipitation. We use hourly next generation (NEXRAD) radar-derived
precipitation to identify convective events, and then compare the location
of precipitation initiation to underlying soil moisture anomalies in the
morning. Overall we find a statistically significant preference for
convective precipitation initiation over drier than normal soils, with over
70 % of events initiating over soil moisture below the long-term median.
The significant preference for precipitation initiation over drier than
normal soils is in contrast with previous studies using satellite-based
precipitation to identify the region of maximum precipitation accumulation.
We evaluated 19 convective events occurring near Lamont, Oklahoma, where
soundings of the atmospheric profile at 06:00 and 12:00 LST are also
available. For these events, soil moisture has strong negative correlations
with the level of free convection (LFC), planetary boundary layer (PBL) height, and
surface temperature changes between 06:00 and 12:00 LST. We also find strong
positive correlations between morning soil moisture and morning-to-afternoon
changes in convective available potential energy and convective inhibition.
In general, the results of this study demonstrate that both positive and
negative soil moisture feedbacks are important in this region of the
USA. |
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