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| Titel |
Characterizing the multi–scale spatial structure of remotely sensed evapotranspiration with information theory |
| VerfasserIn |
N. A. Brunsell, M. C. Anderson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 8, no. 8 ; Nr. 8, no. 8 (2011-08-22), S.2269-2280 |
| Datensatznummer |
250006083
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| Publikation (Nr.) |
 copernicus.org/bg-8-2269-2011.pdf |
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| Zusammenfassung |
| A more thorough understanding of the multi-scale spatial structure of land
surface heterogeneity will enhance understanding of the relationships and
feedbacks between land surface conditions, mass and energy exchanges between
the surface and the atmosphere, and regional meteorological and
climatological conditions. The objectives of this study were to (1) quantify
which spatial scales are dominant in determining the evapotranspiration flux
between the surface and the atmosphere and (2) to quantify how different
spatial scales of atmospheric and surface processes interact for different
stages of the phenological cycle. We used the ALEXI/DisALEXI model for three
days (DOY 181, 229 and 245) in 2002 over the Ft. Peck Ameriflux site to
estimate the latent heat flux from Landsat, MODIS and GOES satellites. We
then applied a multiresolution information theory methodology to quantify
these interactions across different spatial scales and compared the dynamics
across the different sensors and different periods. We note several important
results: (1) spatial scaling characteristics vary with day, but are usually
consistent for a given sensor, but (2) different sensors give different
scalings, and (3) the different sensors exhibit different scaling
relationships with driving variables such as fractional vegetation and near
surface soil moisture. In addition, we note that while the dominant length
scale of the vegetation index remains relatively constant across the dates,
the contribution of the vegetation index to the derived latent heat flux
varies with time. We also note that length scales determined from MODIS are
consistently larger than those determined from Landsat, even at scales that
should be detectable by MODIS. This may imply an inability of the MODIS
sensor to accurately determine the fine scale spatial structure of the land
surface. These results aid in identifying the dominant cross-scale nature of
local to regional biosphere-atmosphere interactions. |
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