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Great Lakes Resource Shed Maps: Watershed MoistureResource sheds delineate the areal distribution of materials, originating over a time interval, prior to their passage through a location of interest at the end of the time interval. For a watershed, a significant location of interest is the watershed's outlet. The images presented below depict previous days' areal distributions of source watershed moisture comprising watershed outflow on selected outflow dates. The RELATIVE data type expresses source material as a percentage of the outflow on the selected day and the ABSOLUTE data type expresses it in cubic meters per day. These maps depict the materials departing during each day that contribute to the outflow on the day selected ('definition one'). The resolution of the maps is 1 km2. These images allow a visual comparison of areal and temporal moisture contributions for an outflow date and offer broad utility in interpreting watershed events. Two other choices in the Data Type field show a different variation of the resource shed maps known as 'definition two'. These can be thought of as the cumulative version of the definition one maps. Instead of showing one day's contribution, each of these maps show the total materials originating over the the past several days that reaches the outlet on the date selected. Absolute and Relative have the same meanings as above. There is software available for the user to build their own maps from
the downloadable data sets. The zipped file contains complete documentation
and test data files. To examine a resource shed of interest, select a watershed, year/month, outflow date, data type, and scale, and then press the "Select Image Series" button. Units in the 'relative' data sets are unitless fractions. Absolute data set units are cm/day. Resource shed maps are currently available from July, 2007 to present.
Last updated: 2008-11-24 | |||||||||||||||||||||||||||||||
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