Atmospheric Ultraviolet Radiance Integrated Code (AURIC): theory, softwarearchitecture, inputs, and selected results

The Atmospheric Ultraviolet Radiance Integrated Code (AURIC) is a software package developed under the sponsorship of the Air Force Phillips Laborator y/Geophysics Directorate (PL/GP) for upper atmospheric radiance modeling fr om the far ultraviolet to the near infrared. It effectively extends the PL/ GP code MODTRAN for calculating atmospheric transmittance and radiance (IR and Rayleigh + aerosol scattering of sunlight) to altitudes above 100 km an d wavelengths down to 1050 Angstrom. The science content of the airglow and upper atmospheric composition codes is presented in this paper. The develo pment has focused on the re-engineering of research codes according to mode rn software standards and on critical reviews of input parameters (cross se ctions, rate coefficients, molecular band constants, etc.). In addition to describing the structure and operation of AURIC, detailed, quantitative des criptions are given of the calculation of photoelectron fluxes, the chemist ry associated with dayglow and nightglow, and the generation of spectral ra diances; Numerous tables are presented of electron impact cross sections an d rate coefficients along with associated bibliographies. Results include p hotoelectron fluxes, volume emission rates, limb profiles of selected emiss ion features, spectral radiances, and densities of ionic and neutral specie s. To document validation activities, many of the results are compared with published rocket and satellite data showing good overall agreement with th e measurements. The airglow modeling capabilities of AURIC make it a powerf ul tool for characterizing optical backgrounds at thermospheric heights, fo r developing remote sensing algorithms, for simulating data from rocket and satellite optical instrumentation, and for conducting science investigatio ns (sensitivity studies and data analyses). (C) 1999 Elsevier Science Ltd. All rights reserved.