Corrections for Atmospheric and Adjacency Effects on High Resolution Sensor Data -a Case Study Using Irs-p6 Liss-iv Data

Path radiance due to aerosols plays an important role over satellite derived reflectance due to higher aerosol optical depth and their seasonal variations. In addition, satellite data from high-resolution sensors are subjected to adjacency effect, which reduces apparent surface contrast by decreasing the top of the atmosphere radiance over bright pixels and increasing the brightness of the dark pixels. In the present study, Second Simulation of Satellite Signal in the solar Spectrum (6S) radiative transfer model was used to analyze influence of atmospheric and adjacency affects over two different study areas corresponds to semi arid and tropical forest regions of India using IRS P6 – LISS-IV satellite data. Ground measurements of surface reflectance over selected crops were conducted to compare satellite derived surface reflectance. 6S model has been calibrated for local conditions using measurements on aerosol optical depth, water vapour and ozone parameters derived from MODIS-TERRA and OMI sensors. The methodology was applied for atmospheric correction of satellite data during intense biomass burning episodes in north-east region of India. Results of the study indicated that satellite reflectance measurements correlated well after correcting the satellite data for atmospheric effects using satellite based atmospheric parameters. Statistical information and seperability analysis over different land use categories suggested improved dynamic range and better seperability after atmospheric corrections. The major outcome of study suggested that atmospheric corrections using satellite derived atmospheric parameters provides a reasonably good data set when ground measurements on atmospheric parameters and surface reflectance are not available.