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Retrieval of Grape Crop Phenology Metrics From Time Series of Optical and SAR Data
Journal
2021 IEEE India Geoscience and Remote Sensing Symposium, InGARSS 2021 - Proceedings
Date Issued
2021-01-01
Author(s)
Sangeetharani, M.
Rajasekaran, Eswar
Narvekar, Parag
Walunj, Sachiin
Shinde, Vilas
Abstract
The aim of this study is to retrieve crop phenological stages such as Season Start Time (SST), peak growth stage and End of Season (EOS) from time series of Sentinel-1 (S1) and Sentinel-2 (S2) over grape crop. Different spectral vegetation indices and Leaf Area Index (LAI) from S2 and backscattering coefficients in VH and VV polarizations from S1 were extracted using the SNAP toolbox. An automated derivative algorithm was developed to extract the crop phenology metrics. Comparison with field observations indicated that vegetation indices from S2 satellite such as NDVI and SAVI yielded better predictions of SST and peak growth stage of the crop, respectively. Cloud cover, especially in the beginning of the cropping season affects the accuracy of the retrieved phenological metrics from optical data. The EOS was better captured by the SAR backscattering coefficient in VH polarization. Combining both optical and SAR data is required for accurate estimation of crop phenological stages.
Subjects