Vol. 8, Issue 6 (2019)

Author(s):
Selvaprakash Ramalingam, Jagadeeswaran Ramasamy, Pazhanivelan sellaperumal, Kumaraperumal Ramalingam, Sivakumar Karthikeyan and GA Deepagaran

Abstract:
An attempt was made to estimate and map soil moisture in Perambalur district of Tamil Nadu using sentinel – 1A Synthetic Aperture Radar (SAR) Data. Sentinel -1A C band data with VV and VH polarization were acquired for the study area during September 2018 to January 2019 at monthly interval. Ground truth collections were performed to estimate in-situ soil moisture both by gravimetric method and using TDR probe at the time of satellite pass. Images were processed using SNAP toolbox and backscattering co-efficient (σ⁰) were generated for each pixel. The backscattering co-efficient value for VV polarization for different dates varied from -14.28 to -2.47 and for VH polarization it was -21.84 to -9.04 since the backscattering co-efficient has a direct relationship with volumetric soil moisture, the same was correlated with in-situ soil moisture. The correlation value is maximum, minimum in the study period dates of (0.62 to -0.49) and (0.69 to -0.72) represented for VH and VV polarization. The negative correlation occurring dates are dense vegetation occurring the field.