Ice Conditions Along the Ohio River as Observed on Landsat Images, 1972-1985.
Lansat images were used to map ice distributions along the Ohio River. Ice conditions were inferred based on image grey tones interpreted using conventional photointerpretation techniques. Portions of the river that appeared black were considered ice-free. Grey tones were interpreted as ice that var...
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| Format: | Text |
| Language: | English |
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1988
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| Online Access: | http://www.dtic.mil/docs/citations/ADA191172 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA191172 |
| Summary: | Lansat images were used to map ice distributions along the Ohio River. Ice conditions were inferred based on image grey tones interpreted using conventional photointerpretation techniques. Portions of the river that appeared black were considered ice-free. Grey tones were interpreted as ice that varied from patches of thin, snow-free solid or fragmented ice, sometimes with open areas, to floes, pans and slush. A white tone represented thick ice or snow-covered ice with few interspersed open areas. Ice that produced grey tones on the images occurred most frequently. Ice typically forms in late December or early January on the Ohio River and is gone by mid to late February. Ice was observed on the upstream section of the river from Pittsburgh to Greenup Dam during 7 of the 13 winters from 1972 to 1985, on the middle section from Greenup Dam to Cannelton Dam during 3 winters, and on the downstream section from Cannelton Dam to the Mississippi River during 4 winters. The most severe and long-lasting ice conditions occurred during the 1976-77 winter when ice covered 65% of the upstream section, 56% of the middle section, and 78% of the downstream section. Keywords: Aerial photography, Remote sensing; River ice, Winter navigation. |
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