Article

Multitemporal C-band radar measurements on wheat fields

Inst. di Radioastronomia, Consiglio Nazionale delle Ricerche, Matera, Italy
IEEE Transactions on Geoscience and Remote Sensing (Impact Factor: 3.51). 08/2003; DOI: 10.1109/TGRS.2003.813531
Source: IEEE Xplore

ABSTRACT This paper investigates the relationship between C-band backscatter measurements and wheat biomass and the underlying soil moisture content. It aims to define strategies for retrieval algorithms with a view to using satellite C-band synthetic aperture radar (SAR) data to monitor wheat growth. The study is based on a ground-based scatterometer experiment conducted on a wheat field at the Matera site in Italy during the 2001 growing season. From March to June 2001, eight C-band scatterometer acquisitions at horizontal-horizontal and vertical-vertical polarization, with incidence angles ranging from 23° to 60°, were taken. At the same time, soil moisture, wheat biomass, and canopy structure were collected. The paper describes the experiment and investigates the radar sensitivity to biophysical parameters at different polarizations and incidence angles, and at different wheat phenological stages. Based on the experimental results, the retrieval of wheat biomass and soil moisture content using Advanced Synthetic Aperture Radar data is discussed.

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    • "Several theoretical and experimental studies, reviewed by McNairn and Brisco (2004), demonstrated the sensitivity of the microwave backscattering coefficient to vegetation and soil parameters, such as plant water content, LAI, soil moisture and soil roughness. For specific crops, such as wheat, simplified retrieval algorithms have also been developed based on the strong relationship observed between crop parameters, such as biomass and LAI, and the ratio of the HH and VV polarised backscattering coefficient, acquired at C-band and at high incidence angles, and based on its relatively low sensitivity to the soil moisture (Brown et al., 2003; Mattia et al., 2003). However, due to the long revisit time of ASAR sensor (i.e. "
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    • "The confidence interval widths were plotted versus the number of pixels used in the calculation which translates directly to ground area. Confidence intervals have been used to establish the suitability of backscatter estimates for soil moisture retrieval (Griffiths & Wooding, 1996; Mattia et al., 2003) but have not been used in the inverse sense to determine the spatial scale over variable surfaces required for an estimate of known quality. 3.3. "
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