Accession Number:

ADA128715

Title:

IR Spectral Signatures of the MILLRACE Debris Cloud

Descriptive Note:

Technical rept.

Corporate Author:

AEROSPACE CORP EL SEGUNDO CA SPACE SCIENCES LAB

Report Date:

1983-04-20

Pagination or Media Count:

57.0

Abstract:

Infrared radiation scattered by the dust and debris cloud generated by the detonation of 600 tons of Ammonium NitrateFuel Oil ANFO high explosive for the MILLRACE test on 16 September 1981 was measured by an infrared spectrometer from a Learjet. The observations were made to characterize the signature of dustdirt clouds and to compare such observations with similar measurements of naturally-occurring water clouds. The instrument used a circular variable interference filter in the spectral interval from 1.8 to 3.4 micrometer to continuously scan solar radiation scattered by clouds. A total of 76 minutes of data was collected beginning with detonation. The cloud reached a stabilization altitude fo 4.4 km MSL 2.9 km AGL. The Learjet flight plan was structured to permit characterizing the scattered radiation as a function of wavelength, scattering angle, and time from detonation. Scattering angles from about 50 to 180 deg were sampled. The expected increase in scattered flux at smaller scattering angles was observed the wavelength dependence of this effect has not yet been fully determined. Cumulus clouds present in the area were also observed. When compared with measurements and calculations for water clouds, the radiation scattered from the dust cloud exhibits higher relative intensity in the wavelength region beyond 3.0 micrometer.

Subject Categories:

  • Atmospheric Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE