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Titel |
Regional estimation of daily to annual regional evapotranspiration with MODIS data in the Yellow River Delta wetland |
VerfasserIn |
L. Jia, G. Xi, S. Liu, C. Huang, Y. Yan, G. Liu |
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 ; 13, no. 10 ; Nr. 13, no. 10 (2009-10-05), S.1775-1787 |
Datensatznummer |
250012017
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Publikation (Nr.) |
copernicus.org/hess-13-1775-2009.pdf |
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Zusammenfassung |
Evapotranspiration (ET) from the wetland of the Yellow River Delta (YRD) is
one of the important components in the water cycle, which represents the
water consumption by the plants and evaporation from the water and the
non-vegetated surfaces. Reliable estimates of the total evapotranspiration
from the wetland is useful information both for understanding the
hydrological process and for water management to protect this natural
environment. Due to the heterogeneity of the vegetation types and canopy
density and of soil water content over the wetland (specifically over the
natural reserve areas), it is difficult to estimate the regional
evapotranspiration extrapolating measurements or calculations usually done
locally for a specific land cover type. Remote sensing can provide
observations of land surface conditions with high spatial and temporal
resolution and coverage. In this study, a model based on the Energy Balance
method was used to calculate daily evapotranspiration (ET) using
instantaneous observations of land surface reflectance and temperature from
MODIS when the data were available on clouds-free days. A time series
analysis algorithm was then applied to generate a time series of daily ET
over a year period by filling the gaps in the observation series due to
clouds. A detailed vegetation classification map was used to help
identifying areas of various wetland vegetation types in the YRD wetland.
Such information was also used to improve the parameterizations in the
energy balance model to improve the accuracy of ET estimates.
This study showed that spatial variation of ET was significant over the same
vegetation class at a given time and over different vegetation types in
different seasons in the YRD wetland. |
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