Surface spectral irradiance and irradiance partitioning in a complex mountain environment: understanding location-dependent topographic effects in satellite imagery

Abstract

Remote sensing of mountain environments is extremely difficult due to atmosphere-topography-landcover couplings that govern the irradiant fluxes. Researchers have not adequately accounted for topographic effects in terms of irradiance components over the landscape. Consequently, we evaluated surface spectral-irradiance components and irradiance partitioning with respect to anisotropic-reflectance correction (ARC). Our work focuses on addressing issues of scale, parameter sensitivity analysis and irradiance partitioning to provide new insights into understanding the complex nature of topographic modulation of the radiation-transfer cascade. We accomplish this by characterizing irradiance components in numerical simulations that account for topographic effects and couplings. Our results reveal atmosphere-topographic couplings associated with irradiance components that are not spatially coincident. Furthermore, we found that commonly utilized adjacent-terrain irradiance parameterization schemes produce different results compared to a more comprehensive parameterization scheme. Parameter sensitivity analysis revealed that the exclusion of topographic effects also produces different results.

Keywords

• adjacent-terrain irradiance
• anisotropic-reflectance correction
• atmosphere-topography-landcover coupling
• radiation-transfer cascade
• surface irradiance