SCIATRAN 2.0 A new radiative transfer model for geophysical applications in the 175 2400 nm spectral region
A successor version of the SCIATRAN radiative transfer model (RTM) has been developed to perform radiative transfer modeling in any observation geometry appropriate to measurements of the scattered solar radiation in the Earth's atmosphere. The model is designed to be used as a forward model in the retrieval of atmospheric constituents from measurements of scattered solar light by satellite, ground-based, or airborne instruments in UV-Vis-NIR spectral region. Furthermore, it can be used to calculate air mass factors or fluxes. The new generation of the SCIATRAN model comprises all features of the latest SCIATRAN 1.2 RTM supporting additionally radiative transfer calculations in a spherical atmosphere. The program is written in FORTRAN 95 and suitable for parallel execution using the OpenMP standard. The wavelength range covered by the radiative transfer model is extended to 175-2380 nm including Schuman-Runge and Herzberg absorption bands of oxygen. The SCIATRAN 2.0 model exhibits the following new capabilities: (i) modeling of the scattered solar radiation in limb viewing geometry as well as any kind of measurements of the scattered radiation within the atmosphere, (ii) corresponding quasi-analytical calculation of weighting functions of atmospheric parameters, (iii) airmass factor calculations for ground-based, space and airborne measurements including off-axis geometry, (v) accounting for photochemically active species, i.e., radiative transfer calculations can be performed using solar zenith angle dependent vertical distributions of atmospheric species, (iv) height resolved radiation fluxes, including actinic fluxes for photolysis rate calculations, (vi) inelastic rotational Raman scattering in any supported viewing geometry, (vii) new effective approximations for radiative transfer modeling in presence of clouds. The SCIATRAN model is freely available via the world wide web for non-commercial scientific applications.