Fast Atmospheric Signature CODE (FASCODE): an update and applications in atmospheric remote sensing

摘要

Abstract: The U.S. Air Force has long maintained an `exact'accelerated line-by-line (LBL) radiative transfermodel, the Fast Atmospheric Signature CODE (FASCODE),appropriate for applications in both the laboratory andany arbitrary line-of-sight in the atmosphere. Thefirst version was released in 1978 with optimized Voigtline shape decomposition and layering algorithms; ithad a speed advantage of about 100 over existing fixedfrequency LBL codes. The current version of FASCODE,FASCOD3, is fully compatible with the HITRAN92database, including access to the temperature-dependentcross sections for heavy molecules (e.g.,chloro-fluorocarbons/CFCs, etc.). Some new features ofFASCOD3 are: line coupling algorithms for both 15micron CO$-2$/ and the mm lines of O$-2$/; non-localthermodynamic equilibrium models; updated H$-2$/Ocontinuum; multiple scattering capability; and laseroptions for lidar modeling applications. Because of itsspeed over other LBL codes and extensive validationsagainst measurements, FASCOD3 is increasingly beingused as a high resolution remote sensing data analysistool from microwave and infrared (IR) to ultraviolet(UV) spectral ranges. !27