Emission inclusion in Successive Orders of Scattering radiative transfer scheme.

Abstract:

The Successive Orders of Scattering (SOS) radiative transfer scheme was introduced by Lenoble et al. (2007). This approach to solve the radiative transfer equation has been successfully applied in different applications to model upward and downward radiation, include surface boundary conditions, and it enables a direct implementation of aerosol and Rayleigh scattering and also gaseous absorption. However, the original development of this approach by Lenoble et al. [2007] is restricted just to the visible part of the spectrum. It does not account the radiation coming from the thermal emission of the different atmospheric components and the surface.

In this new implementation of the original idea of the SOS scheme, source functions are extended to include Planck emission function in order to account with the radiation coming from both scattering and emission origin in single and multiple scattering regimes.
The validation of this new scheme for emission radiation has been done against a consolidated and widely spread radiative transfer code based on the discrete-ordinated method, DISORT [Stamnes et al., 1988]. The difference in the radiance obtained from both codes under the same conditions is on average below 0.5%.

The development is implemented in the frame of GRASP (Generalized Retrieval of Aerosol and Surface Properties) algorithm [Dubovik et al., 2011, 2014], there SOS approach has been already adapted for modeling atmospheric radiation in visible spectrum. Thus, it is expected that the described development will be employed for synergetic atmospheric retrieval using both photometric and hyperspectral observations in visible and thermal IR part of the spectrum.