Accession Number:

ADA025377

Title:

Infrared Continuum Absorption by Atmospheric Water Vapor in the 8-12- Micrometer Window

Descriptive Note:

Final rept. Oct 1975-Mar 1976

Corporate Author:

INSTITUTE FOR DEFENSE ANALYSES ALEXANDRIA VA SCIENCE AND TECHNOLOGY DIV

Report Date:

1976-04-01

Pagination or Media Count:

29.0

Abstract:

We have carried out a detailed analysis of several long-path-length transmission measurements in the 8 to 12 micrometer atmospheric window in order to determine the extinction coefficient due to the water vapor continuum. Our results indicate that three modifications to the current LOWTRAN atmospheric transmission model are required. The first two corrections are an improved fit to the pure water vapor continuum absorption coefficient and the elimination of the atmospheric broadened continuum term. Finally, and most critically, a strong measured temperature dependence must be included in the water vapor continuum absorption coefficient. For path lengths ranging from 10 to 50 km, failure to incorporate these corrections can lead to errors in the computed transmission ranging from factors of 2 to more than 10,000.

Subject Categories:

  • Infrared Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE