Browsing by Author "G.D. Bairagi"

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Crop phenology and soil moisture applications of SCATSAT-1
(Indian Academy of Sciences, 2019) Nilima R. Chaube; Sasmita Chaurasia; Rojalin Tripathy; Dharmendra Kumar Pandey; Arundhati Misra; B.K. Bhattacharya; Prakash Chauhan; Kiran Yarakulla; G.D. Bairagi; Prashant Kumar Srivastava; Preeti Teheliani; S.S. Ray
SCATSAT-1 measures the backscattering coefficient over land surfaces, which is a function of vegetation structure, surface roughness, soil moisture content, incidence angle and dielectric properties of vegetation. Scatterometer image reconstruction techniques provide fine resolution data to explore the emerging applications over land by using ambiguous backscatter from land. In this paper, 2 km resolution products of ISRO's scatterometer SCATSAT-1 are exploited for land target detection, rice crop phenology stages detection for kharif and rabi seasons and estimation of relative soil moisture over parts of India. Temporal and spatial backscatter changes are due to seasonal and changes in Land Use Land Cover. Crop phenology stages such as transplanting, maximum tillering, panicle emergence and physiological maturity stages are identified by analysing SCATSAT-1 time series along with NDVI and findings are supported by appropriate ground truth observations and crop cutting experiment (CCE) data. The relative soil moisture change detection is validated with in situ ground truth measurements using Hydraprobe, carried for SCATSAT-1 ascending and descending passes. © 2019 Current Science Association, Bengaluru.
Retrieval of wheat Leaf Area Index using price approach based on inversion of canopy reflectance model
(2005) R.P. Singh; V.K. Dadhwal; K.P. Singh; R.R. Navalgund; R. Sharma; G.D. Bairagi; S.A. Raza; N.K. Sharma
This paper reports estimation of the Leaf Area Index (LAI) of wheat crop from IRS-LISS-III data using Price (1993) approach. Empirical approach for LAI estimation with different NDVI estimation procedures viz. radiance, apparent reflectance and dark object subtraction (DOS) based atmospheric correction were also evaluated. Validation of LAl retrieval and NDVI normalizations were carried out using field level measurements of crop LAI and spectral property using canopy analyzer and spectro-radiometer, respectively over selected fields in Bhopal District, Madhya Pradesh. It was observed that empirical relations are sensitive to the NDVI estimation approach and DOS method performed better as compared to other two approaches. It was also observed that LAI estimation from Price algorithm is sensitive to the crop attenuation coefficients. Crop specific attenuation coefficients reported in literature for Indian cultivars gave higher accuracy. The root mean square (RMS) error of 0.77 for LAI estimation was achieved using above described approach.