Ice Conditions Along the Allegheny and Monongahela Rivers as Observed on Landsat Images, 1972-1985
Landsat images were used to map ice distributions along a 72-mile section of the Allegheny River, and the 129-mile-long Monongahela River. River reaches with grey ice and white ice were mapped based on images tones using conventional photointerpretation techniques. Portions of a river that appeared...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
1988
|
| Subjects: | |
| Online Access: | http://www.dtic.mil/docs/citations/ADA196432 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA196432 |
| Summary: | Landsat images were used to map ice distributions along a 72-mile section of the Allegheny River, and the 129-mile-long Monongahela River. River reaches with grey ice and white ice were mapped based on images tones using conventional photointerpretation techniques. Portions of a river that appeared black were mapped as ice free, although thin, transparent ice could also appear black. Grey tones were produced by ice that varied from patches of solid or fragmented ice with large open-water areas, to floes, pans, slush, or thin ice mixed with open areas. A white tone was produced by thick ice or snow-covered ice with very small or no open areas. Ice that produced grey tones was more frequent than ice that produced a white tone. Ice was observed on the Allegheny River during 10 of the 13 winters from 1972 to 1985, with the most severe ice conditions in 1976-77 when 100% of the river showed evidence of some ice cover, and 89% of the river was covered with white ice. The Monongahela River had ice during 7 winters. Grey ice and white ice were observed covering the entire Monongahela River during the 1983-84 winter. During 1976-77, grey and white ice covered 94%. |
|---|