Comparative Analysis of Satellite Remotely-Sensed Surface Energy Flux and Ground-Based Observation in the Sichuan Basin

抄録

Integrating the clear-sky NOAA/AVHRR satellite data with station meteorological observations, we conduct a remote sensing estimation of surface energy fluxes of the Sichuan Basin based on surface energy balance. The correlation between the estimation of satellite pixel and the ground-based observed value of Wenjiang Atmospheric Boundary Layer Observation Station is analyzed to verify the satellite remotely-sensed surface energy flux. Result indicates that the distributions of satellite remotely-sensed surface energy fluxes are consistent with those of the underlying surface. There exist remarkable positive correlations among the satellite-estimated net radiation flux, soil heat flux, sensible heat flux, and the ground-based observed values of key components. All correlation coefficients significantly exceed 0.9. Hence, the remotely-sensed estimations of net radiation flux, soil heat flux, and sensible heat flux are reliable to a certain extent. Since the surface energy balance at Wenjiang test site is usually unclosed, the correlation coefficient between the satellite pixel latent heat flux estimated by surface energy balance method and the value measured by eddy covariance method of the key components is only 0.717. If the unclosed value of surface energy balance is taken into consideration, the correlation coefficient increases to 0.945, meaning that the deviation between the two decreases obviously. It is thus unadvisable to use the residual of surface energy balance equation to estimate the latent heat flux in the Sichuan Basin, because the unclosed energy can cause large errors. Closure of surface energy is required when the residual method is applied.