4A/OP
4A/OPor,Automatized Atmospheric Absorption Atlas, is an operational fast and accurateradiative transfermodel for theinfrared.
4A/OP is a user-friendlysoftwarefor various scientific applications (surface, balloon or space-based observations), co-developed by LMD (Laboratoire de Meteorologie Dynamique) andNOVELTISwith the support ofCNES(the French Space Agency).
NOVELTIS is in charge of the industrialization and the distribution of the LMD 4A radiative transfer model. 4A allows fast and accurate computation oftransmittanceandradiance,owing to the use of a comprehensivedatabase(atlases) ofmonochromaticoptical thicknesses for up to 43 atmospheric molecular species. Precomputed once and for all, the atlases are created by using the line-by-line and layer-by-layer model,STRANSAC,with up to date physics. Owing to the computation ofJacobians(partial derivativesof the radiance with respect to atmospheric variables), the 4A model can be easily coupled with an inversion algorithm for the retrieval of atmospheric temperature or composition from infrared radiance measurements.
It usesspectroscopyfrom the regularly updatedGEISAspectral linedata catalog. Other spectroscopy databanks can be used.
The 4A/OP software is a version of the 4A code for distribution to registered users. This version is regularly updated and improved and contains agraphical user interfaceand a reference documentation.
This software is used by several research groups and can be integrated in operational processing chains.[citation needed]In particular, 4A/OP is the reference radiative transfer model for the CNES/EUMETSAT Infrared Atmospheric Sounder Interferometer (IASI) level 1 Cal/Val and level 1 operational processing.
See also
[edit]- List of atmospheric radiative transfer codes
- Atmospheric radiative transfer codes
- Absorption spectrum
- GEISA
References
[edit] | This article includes alist of references,related reading,orexternal links,but its sources remain unclear because it lacksinline citations.(April 2009) |
- Scott, N.A. (1974) A direct method of computation of transmission function of an inhomogeneous gaseous medium: description of the method and influence of various factors. J. Quant. Spectrosc. Radiat. Transfer, 14, 691-707.
- Scott, N.A. and A. Chedin (1981) A fast line-by-line method for atmospheric absorption computations: The Automatized Atmospheric Absorption Atlas. J. Appl. Meteorol., 20, 802-812.
- Chaumat, L., N. Decoster, C. Standfuss, B. Tournier, R. Armante and N. A. Scott (2006) 4A/OP Reference Documentation, NOV-3049-NT-1178-v3.4, NOVELTIS, LMD/CNRS, CNES, 261 pp.
- Jacquinet-Husson, N. et al. (1999) The 1997 spectroscopic GEISA data bank. J. Quant. Spectrosc. Radiat. Transfer, 62, 205-254.