Evaluating the affect of seasonal soil moisture and vegetation change on C-Band SAR backscatter over corn fields in SW Ontario

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MacDougall, Joshua
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University of Guelph

Soil moisture estimates using C-band SAR over agricultural fields have a backscatter signal that saturates early in the growing season, especially at high incidence angles. This research derives these saturation points using a statistical approach on corn fields just south of Elora, Ontario using RADARSAT-2 overpassess with incidence angles ≥45°. Vegetation water content (VWC) and backscatter are segmented before and after saturation, as well as overall to assess their relationship. These saturation points are used to segment in-situ soil moisture and backscatter. The saturation points of VWC are 0.14, 0.17, and 1.69 kg m-2 for HH, HV, and VV polarizations respectively. The results indicate that VWC dominates the backscatter until saturation but that soil moisture is always a contributing factor to the backscatter signal. VV exhibited the latest saturation point and the correlations it exhibited with VWC and soil moisture were unexpected and require further investigation.

SAR, remote sensing, agriculture, soil moisture