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| Titel |
Annual evapotranspiration retrieved from satellite vegetation indices for the eastern Mediterranean at 250 m spatial resolution |
| VerfasserIn |
D. Helman, A. Givati, I. M. Lensky |
| 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 ; 15, no. 21 ; Nr. 15, no. 21 (2015-11-11), S.12567-12579 |
| Datensatznummer |
250120156
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| Publikation (Nr.) |
 copernicus.org/acp-15-12567-2015.pdf |
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| Zusammenfassung |
| We present a model to retrieve actual evapotranspiration (ET) from
satellites' vegetation indices (Parameterization of Vegetation Indices for
ET estimation model, or PaVI-E) for the eastern Mediterranean (EM)
at a spatial resolution of 250 m. The model is based on the empirical
relationship between satellites' vegetation indices (normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) from
MODIS) and total annual ET (ETAnnual) estimated at 16 FLUXNET
sites,
representing a wide range of plant functional types and ETAnnual.
Empirical relationships were first examined separately for (a) annual
vegetation systems (i.e. croplands and grasslands) and (b) systems with
combined annual and perennial vegetation (i.e. woodlands, forests, savannah
and shrublands). Vegetation indices explained most of the variance in
ETAnnual in those systems (71 % for annuals, and 88 % for combined
annual and perennial systems), while adding land surface temperature data
in a multiple-variable regression and a modified version of the Temperature and Greenness model did not
result in better correlations (p > 0.1). After establishing
empirical relationships, PaVI-E was used to retrieve ETAnnual for the
EM from 2000 to 2014. Models' estimates were highly correlated (R = 0.92,
p < 0.01) with ETAnnual calculated from water catchment balances
along rainfall gradient of the EM. They were also comparable to the
coarser-resolution ET products of the Land Surface Analysis Satellite Applications Facility (LSA-SAF MSG ETa, 3.1 km) and MODIS (MOD16, 1 km)
at 148 EM basins with R of 0.75 and 0.77 and relative biases of 5.2 and
−5.2 %, respectively (p < 0.001 for both). In the absence of
high-resolution (< 1 km) ET models for the EM the proposed model is
expected to contribute to the hydrological study of this region, assisting in
water resource management, which is one of the most valuable resources of
this region. |
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