Quantification and comparison of spectral characteristics of sensors on board Resourcesat-1 and Resourcesat-2 satellites

Abstract

This letter presents quantification and comparison of spectral characteristics of three similar sensors, namely Linear Imaging Self-Scanning Sensor (LISS)-III, LISS-IV and Advanced Wide Field Sensor (AWiFS) on board Indian Remote Sensing (IRS) satellites Resourcesat-1 (RS1) and Resourcesat-2 (RS2). Theoretical estimates of three critical spectral characteristics, effective bandwidth (Δλ), central wavelength (λ_c) and bandpass solar exoatmospheric irradiance (E ₀), have been computed based on the laboratory measurements of the relative spectral response (RSR) for each spectral band. A comparative analysis between two estimates computed through the moment method and the full width at half maximum (FWHM) method showed noticeable differences of the order of 4.4–14.1 nm in Δλ and λ_c for the corresponding band of Resourcesat sensors. A coefficient of variation (CV) of the order of 0.1–1.3% was noticed in E ₀ among various Resourcesat sensors, which could induce a difference of 0.26–3.27% in the estimation of top-of-atmosphere (TOA) reflectance. The variations in spectral characteristics among the Resourcesat sensors should be taken into account when comparisons are made between measurements from sensors on board RS1 and RS2 satellites, for example, for long-term monitoring of the Earth's environment.

Acknowledgements

We acknowledge Dr. J.S. Parihar, Deputy Director, EPSA, SAC, and Dr. Sushma Panigrahy, Group Director, ABHG, EPSA, SAC, for their support to carry out this study. We also thank anonymous reviewers for their suggestions to improve the manuscript.