Arctic multiyear ice classification and summer ice cover using passive microwave satellite data
- NASA Goddard Space Flight Center, Greenbelt, MD (USA)
The ability to classify and monitor Arctic multiyear sea ice cover using multispectral passive microwave data is studied. Sea ice concentration maps during several summer minima have been analyzed to obtain estimates of ice surviving the summer. The results are compared with multiyear ice concentrations derived from data the following winter, using an algorithm that assumes a certain emissivity for multiyear ice. The multiyear ice cover inferred from the winter data is approximately 25 to 40% less than the summer ice cover minimum, suggesting that even during winter when the emissivity of sea ice is most stable, passive microwave data may account for only a fraction of the total multiyear ice cover. The difference of about 2 {times} 10{sup 6} km{sup 2} is considerably more than estimates of advection through Fram Strait during the intervening period. It appears that as in the Antarctic, some multiyear ice floes in the Arctic, especially those near the summer marginal ice zone, have first-year ice or intermediate signatures in the subsequent winter. A likely mechanism for this is the intrusion of seawater into the snow-ice interface, which often occurs near the marginal ice zone or in areas where snow load is heavy. Spatial variations in melt and melt ponding effects also contribute to the complexity of the microwave emissivity of multiyear ice. Hence the multiyear ice data should be studied in conjunction with the previous summer ice data to obtain a more complete characterization of the state of the Arctic ice cover. The total extent and actual areas of the summertime Arctic pack ice were estimated to be 8.4 {times} 10{sup 6} km{sup 2}, respectively, and exhibit small interannual variability during the years 1979 through 1985, suggesting a relatively stable ice cover.
- OSTI ID:
- 6103151
- Journal Information:
- Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 95:C8; ISSN 0148-0227; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540310* -- Environment
Aquatic-- Basic Studies-- (1990-)
ALGORITHMS
ANNUAL VARIATIONS
ARCTIC REGIONS
CLASSIFICATION
HYDROGEN COMPOUNDS
ICE
MAPPING
MATHEMATICAL LOGIC
MICROWAVE SPECTRA
MONITORING
OXYGEN COMPOUNDS
POLAR REGIONS
SEAS
SEASONAL VARIATIONS
SEAWATER
SPECTRA
SURFACE WATERS
VARIATIONS
WATER