Accession Number : AD0860551

Title :   Clear and Cloudy Sky Radiance Measurements for 0 to 23 Degrees Elevation in the 7.0- to 13.5- Micron Spectral Region.

Descriptive Note : Technical publication,

Corporate Author : NAVAL WEAPONS CENTER CHINA LAKE CA

Personal Author(s) : LaBaw, Kenneth B.

Report Date : SEP 1969

Pagination or Media Count : 16

Abstract : Infrared sky radiation measurements gathered by a 3-milliradian spatial resolution area-scanning radiometer are presented and discussed. The data are from clear sky and stratocumulus clouds at about 8,000 feet altitude. The measurements are for four spectral regions: 7.0 to 13.5, 7.5 to 8.5, 7.0 to 9.0, and 8.5 to 12.5 microns. Results are given as blackbody equivalent temperature with a conversion graph for effective watts/(sq cm . sr). Time of day and azimuth direction are found to be insignificant parameters. Questions on cloud emissivity, solar scattering, and upwelling ground radiation are not quantitatively answered. The importance of spatial resolution is demonstrated. A set of measurements with the sun hidden behind fractocumulus clouds does not show forward scattering as was expected based on calculations by Deirmendjian. Clear sky measurements, taken for reference, agree well with data reported by Bell and others. (Author)

Descriptors :   (*COMBAT SURVEILLANCE, AERIAL PHOTOGRAPHY), (*CLOUDS, SKY BRIGHTNESS), (*SKY BRIGHTNESS, MEASUREMENT), (*SURFACE TARGETS, INFRARED SCANNING), RADIOMETERS, CLOUD COVER, STRATUS CLOUDS, CUMULUS CLOUDS, BACKGROUND, EMISSIVITY, SCATTERING, VISIBILITY, BLACKBODY RADIATION, RESOLUTION.

Subject Categories : Cartography and Aerial Photography
      Military Operations, Strategy and Tactics
      Infrared Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE