Form Approved
REPORT DOCUMENTATION PAGE
OMB No. 0704-0188
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1. AGENCY USE ONLY (Leave blank)
2. REPORT DATE
3. REPORT TYPE AND DATES COVERED
May 1996
4. TITLE AND SUBTITLE
5. FUNDING NUMBERS
The Optical Properties of Sea Ice
Office of Naval Research
Contracts
N0001495MP30002
6. AUTHORS
N0001495MP30031
Donald K. Perovich
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
8. PERFORMING ORGANIZATION
REPORT NUMBER
U.S. Army Cold Regions Research and Engineering Laboratory
72 Lyme Road
Monograph 96-1
Hanover, New Hampshire 03755-1290
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)
10. SPONSORING/MONITORING
AGENCY REPORT NUMBER
Office of Naval Research
800 N. Quincy Street
Arlington, Virginia 22217-5000
11. SUPPLEMENTARY NOTES
12a. DISTRIBUTION/AVAILABILITY STATEMENT
12b. DISTRIBUTION CODE
Approved for public release; distribution is unlimited.
Available from NTIS, Springfield, Virginia 22161
13. ABSTRACT (Maximum 200 words)
Sea ice is a translucent material with an intricate structure and complex optical properties. Understanding the
reflection, absorption, and transmission of shortwave radiation by sea ice is important to a diverse array of
scientific problems, including those in ice thermodynamics and polar climatology. Radiative transfer in sea ice
is a combination of absorption and scattering. Differences in the magnitude of sea ice optical properties are due
primarily to differences in scattering. Spectral variations are mainly a result of absorption. Changes in such
optical properties as the albedo, reflectance, transmittance, and extinction coefficient are directly related to
changes in the state and structure of the ice. Physical changes that enhance scattering, such as the formation of
air bubbles due to brine drainage, result in larger albedos and extinction coefficients. The albedo is quite
sensitive to the surface state. If the ice has a snow cover, albedos are large. In contrast, the presence of liquid
water on a bare ice surface causes a decrease in albedo, which is more pronounced at longer wavelengths. Sea-
ice optical properties depend on the volume of brine and air and on how the brine and air are distributed.
14. SUBJECT TERMS
15. NUMBER OF PAGES
33
Albedo
Optical properties
Sea ice
16. PRICE CODE
Absorption
Scattering
17. SECURITY CLASSIFICATION
18. SECURITY CLASSIFICATION
19. SECURITY CLASSIFICATION
20. LIMITATION OF ABSTRACT
OF REPORT
OF THIS PAGE
OF ABSTRACT
UNCLASSIFIED
UNCLASSIFIED
UNCLASSIFIED
UL
Standard Form 298 (Rev. 2-89)
NSN 7540-01-280-5500
Prescribed by ANSI Std. Z39-18
298-102
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