Accession Number:

ADA214337

Title:

MODTRAN: A Moderate Resolution Model for LOWTRAN 7

Descriptive Note:

Final rept. 12 May 1986-Apr 1989

Corporate Author:

SPECTRAL SCIENCES INC BURLINGTON MA

Report Date:

1989-04-30

Pagination or Media Count:

44.0

Abstract:

The LOWTRAN computer codes, with LOWTRAN 7 being the most current version, are widely used to calculate atmospheric transmittance andor radiance in the infrared, visible and near ultraviolet spectral regions LOWTRAN 7 has been extended to include the microwave spectral region. The code is easily used, runs quickly and provides the user with a wide variety of atmospheric models and options. Its spectral resolution is 20 1cm Full WidthHalf Maximum FWHM with calculations being done in 5 1cm increments. This report describes work done to increase LOWTRANs spectral resolution from 20 to 2 1cm FWHM. Specifically, the technical objectives for this program were 1 to develop algorithms providing 2 1cm resolution FWHM 2 to model molecular absorption of atmospheric molecules as a function of temperature and pressure 3 to calculate band model parameters for twelve LOWTRAN molecular species and 4 to integrate the LOWTRAN 7 capabilities into the new algorithms, maintaining compatibility with the multiple scattering option. MODTRAN, the final product of this effort, is a moderate resolution LOWTRAN code. Molecular absorption is calculated in 1 1cm spectral bins, while the other parts of the calculation remain unchanged. The molecular species affected are water vapor, carbon dioxide, ozone, nitrous oxide, carbon monoxide, methane, oxygen, nitric oxide, sulfur dioxide, nitrogen dioxide, ammonia and nitric acid.

Subject Categories:

  • Atmospheric Physics
  • Computer Programming and Software

Distribution Statement:

APPROVED FOR PUBLIC RELEASE