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| Titel |
Topographic effects on solar radiation distribution in mountainous watersheds and their influence on reference evapotranspiration estimates at watershed scale |
| VerfasserIn |
C. Aguilar, J. Herrero, M. J. Polo |
| 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 ; 14, no. 12 ; Nr. 14, no. 12 (2010-12-10), S.2479-2494 |
| Datensatznummer |
250012526
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| Publikation (Nr.) |
 copernicus.org/hess-14-2479-2010.pdf |
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| Zusammenfassung |
| Distributed energy and water balance models require time-series surfaces of
the climatological variables involved in hydrological processes. Among them,
solar radiation constitutes a key variable to the circulation of water in
the atmosphere. Most of the hydrological GIS-based models apply simple
interpolation techniques to data measured at few weather stations
disregarding topographic effects. Here, a topographic solar radiation
algorithm has been included for the generation of detailed time-series solar
radiation surfaces using limited data and simple methods in a mountainous
watershed in southern Spain. The results show the major role of topography
in local values and differences between the topographic approximation and
the direct interpolation to measured data (IDW) of up to +42% and
−1800% in the estimated daily values. Also, the comparison of the
predicted values with experimental data proves the usefulness of the
algorithm for the estimation of spatially-distributed radiation values in a
complex terrain, with a good fit for daily values (R2 = 0.93) and the
best fits under cloudless skies at hourly time steps. Finally,
evapotranspiration fields estimated through the ASCE-Penman-Monteith
equation using both corrected and non-corrected radiation values address the
hydrologic importance of using topographically-corrected solar radiation
fields as inputs to the equation over uniform values with mean differences
in the watershed of 61 mm/year and 142 mm/year of standard deviation. High
speed computations in a 1300 km2 watershed in the south of Spain with
up to a one-hour time scale in 30 × 30 m2 cells can be easily carried
out on a desktop PC. |
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