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| Titel |
Assessment of the consistency among global microwave land surface emissivity products |
| VerfasserIn |
H. Norouzi, M. Temimi, C. Prigent, J. Turk, R. Khanbilvardi, Y. Tian, F. A. Furuzawa, H. Masunaga |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 3 ; Nr. 8, no. 3 (2015-03-11), S.1197-1205 |
| Datensatznummer |
250116210
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| Publikation (Nr.) |
 copernicus.org/amt-8-1197-2015.pdf |
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| Zusammenfassung |
The goal of this work is to intercompare four global land surface emissivity
products over various land-cover conditions to assess their consistency. The
intercompared land emissivity products were generated over a 5-year period
(2003–2007) using observations from the Advanced Microwave Scanning
Radiometer – Earth Observing System (AMSR-E), the Special Sensor Microwave
Imager (SSM/I), the Tropical Rainfall Measuring Mission (TRMM) Microwave
Imager (TMI), and WindSat. First, all products were reprocessed in the same
projection and spatial resolution as they were generated from sensors with
various configurations. Then, the mean value and standard deviations of
monthly emissivity values were calculated for each product to assess the
spatial distribution of the consistencies/inconsistencies among the products
across the globe. The emissivity products were also compared to soil moisture
estimates and a satellite-based vegetation index to assess their
sensitivities to changes in land surface conditions.
Results show the existence of systematic differences among the products.
Also, it was noticed that emissivity values in each product have similar
frequency dependency over different land-cover types. Monthly means of
emissivity values from AMSR-E in the vertical and horizontal polarizations
seem to be systematically lower than the rest of the products across various
land-cover conditions which may be attributed to the 01:30/13:30 LT overpass time of the sensor and possibly
a residual skin temperature effect in the product. The standard deviation of
the analyzed products was lowest (less than 0.01) in rain forest regions
for all products and highest at northern latitudes, above 0.04 for AMSR-E
and SSM/I and around 0.03 for WindSat. Despite differences in absolute
emissivity estimates, all products were similarly sensitive to changes in
soil moisture and vegetation. The correlation between the emissivity
polarization differences and normalized difference
vegetation index (NDVI) values showed similar spatial distribution
across the products, with values close to the unit except over densely
vegetated and desert areas. |
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