The operational version of 4A, a fast and accurate radiative transfer model for the Thermal, Short Wave and Far Infrared
|The 4A/OP software package is the operational version of the fast and accurate radiative transfer model 4A (Automatized Atmospheric Absorption Atlas), developed, maintained and validated at LMD.
The 4A high spectral resolution line-by-line radiative transfer model (Scott and Chédin, 1981) pioneered the idea of bypassing the time-consuming line-by-line process by calculating once and for all Look-Up-Tables (LUT) of compressed monochromatic optical depths («the Atlases»).
Originally designed for the Earth atmosphere, the 4A concept has easily and successfully been extended to the Jovian atmosphere in the frame of the Voyager experiment.
Related to the current and future space activities or planned experiments, the spectral domain extends now from 100 to 14000 cm-1.
The operational version of 4A was developed in the late 90’s by Noveltis and LMD, under the aegis and with the support of CNES. Since then, 4A/OP is regularly improved, updated and extended by LMD, CNES and NOVELTIS.