FAST RADIATIVE TRANSFER FOR MULTISPECTRAL SPACE-BASED SENSORS

We present the Angstrom Polynomial Approximation Radiative Transfer (APART) model, a simplified radiative transfer (RT) model for visible and near infrared (VNIR) and shortwave infrared (SWIR) satellite sensors in the the 350nm-2400nm wavelength range, fast enough for direct pixel-wise RT computation. The model contains relatively straightforward parameterized approximations of complex processes such as multiple scattering and Rayleigh reflectance. In formulating our model, we adhere as closely as possible to the structure of 6S [1], a well-known and highly-validated RT model used by the remote sensing community. We phrase our equations as functions of physically meaningful quantities such as water vapor content, ozone content, aerosol optical depth (AOD), and sun/view geometries. We fit APART model parameters to 6S simulations and validate our results against 6S for many combinations AOD and solar/view geometry.