Deriving Surface Reflectance From Visible/Near Infrared and Ultraviolet Satellite Observations Through the Community Radiative Transfer Model

Earth's surface reflectance is an important parameter affecting ultraviolet (UV) and visible (VIS) radiance calculations at the top of the atmosphere because many UV and VIS channels can acquire information about the surface and atmosphere. This article provides the theoretical basis for deriving the surface reflectance from satellite-measured UV and VIS observations at window and lower sounding channels with the help of the community radiative transfer model (CRTM) and collocated atmospheric profiles such as ozone, water vapor, and aerosols. Cirrus cloud may be included in the calculation as long as the observations contain enough reflected radiation from the surface. An explicit equation with three scalar parameters $\alpha $, $\beta $, and $\delta $ is obtained for users to calculate Lambertian surface reflectance from the observation. The expressions for the three parameters are somewhat complicated and computationally expansive. We found a simple and smart way that can exactly calculate the three parameters with quasi-linear functions. Numerical experiments using the CRTM simulations have demonstrated the algorithm accuracy for the surface reflectance retrieval better than 2.0E-14. As a case study, measured surface reflectance and the derived surface reflectance over desert from satellite UV measurements are compared. The derived surface reflectance from Suomi National Polar-orbiting Partnership. Visible Infrared Imaging Radiometer Suite (VIIRS) observations and the VIIRS reflectance product are compared as well. In addition, this methodology can also be used to calculate microwave and infrared surface emissivity with scatterings and solar radiation by adding the surface Planck radiance at the surface temperature.