An adjustment of coefficients for SMAC using MODIS red band

MODIS 가시 채널을 사용한 SMAC 계수 개선

  • 박수재 (부경대학교 위성정보과학과) ;
  • 이창석 (부경대학교 위성정보과학과) ;
  • 염종민 (부경대학교 위성정보과학과) ;
  • 이가람 (부경대학교 위성정보과학과) ;
  • 피경진 (부경대학교 위성정보과학과) ;
  • 한경수 (부경대학교 위성정보과학과) ;
  • 김영섭 (부경대학교 위성정보과학과)
  • Published : 2009.03.25

Abstract

In this study, Simplified Method for the Atmospheric Correction (SMAC) radiative transfer model (RTM) used to retrieve surface reflectance from MODIS Top Of Atmosphere (TOA) reflectance (MOD02). SMAC code provides coefficients which were previously yielded by Second Simulation of the Satellite Signal in the Solar Spectrum (6S) for each satellite sensor. We conducted error analysis of SMAC RTM using MOD02 over comparison with MODIS surface reflectance (MOD09) which was provided from 6S. It showed that low accuracy values such as, $R^2$ : 0.6196, Root Means Square Error (RMSE) : 0.00031, bias : - 0.0859. Thus sensitivity analysis of input parameters and coefficients was conducted to searching error sources. Coefficients about $\tau_p$ (average AOD) are more influence than any other coefficients of $\tau_{a550}$ (Aerosol Optical Depth at 550nm) from sensitivity test. Calibrated coefficients of $\tau_p$ from regression analysis were used to surface reflectance which showed that improve accuracy of surface reflectance ($R^2$ : 0.827, RMSE : 0.00672, bias : - 0.000762).

Keywords