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| Titel |
Combined use of optical and radar satellite data for the monitoring of irrigation and soil moisture of wheat crops |
| VerfasserIn |
R. Fieuzal, B. Duchemin, L. Jarlan, M. Zribi, F. Baup, O. Merlin, O. Hagolle, J. Garatuza-Payan |
| 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 ; 15, no. 4 ; Nr. 15, no. 4 (2011-04-05), S.1117-1129 |
| Datensatznummer |
250012740
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| Publikation (Nr.) |
 copernicus.org/hess-15-1117-2011.pdf |
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| Zusammenfassung |
| The objective of this study is to get a better understanding of radar signal
over irrigated wheat fields and to assess the potentialities of radar
observations for the monitoring of soil moisture. Emphasis is put on the use
of high spatial and temporal resolution satellite data (Envisat/ASAR and
Formosat-2). Time series of images were collected over the Yaqui irrigated
area (Mexico) throughout one agricultural season from December 2007 to May 2008, together with measurements of soil and vegetation characteristics and
agricultural practices. The comprehensive analysis of these data indicates
that the sensitivity of the radar signal to vegetation is masked by the
variability of soil conditions. On-going irrigated areas can be detected all
over the wheat growing season. The empirical algorithm developed for the
retrieval of topsoil moisture from Envisat/ASAR images takes advantage of
the Formosat-2 instrument capabilities to monitor the seasonality of wheat
canopies. This monitoring is performed using dense time series of images
acquired by Formosat-2 to set up the SAFY vegetation model. Topsoil moisture
estimates are not reliable at the timing of plant emergence and during plant
senescence. Estimates are accurate from tillering to grain filling stages
with an absolute error about 9% (0.09 m3 m−3, 35% in relative value).
This result is attractive since topsoil moisture is estimated at a high
spatial resolution (i.e. over subfields of about 5 ha) for a large range of
biomass water content (from 5 and 65 t ha−1 independently from the
viewing angle of ASAR acquisition (incidence angles IS1 to IS6). |
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