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A synoptic climatology of eastern North America with mesoscale resolution




Moran, Michael D., author
Wesley, Douglas Alan, author
Pielke, Roger A., author
Department of Atmospheric Science, Colorado State University, publisher

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A subjective synoptic classification scheme has been used to categorize the dominant daily synoptic weather pattern for each grid square in a 5-square X 7-square grid placed over eastern North America for the five-year period from 1975 to 1979. Seven synoptic categories were used in the classification scheme: (1) warm sector of an extratropical cyclone; (2) region of overrunning north of a warm front; (3) region of cyclonic isobaric curvature behind a cold front; (4) polar anticyclone; (5) subtropical anticyclone or ridge; (6) tropical cyclone; and (7) unclassifiable pattern. The grid extends from 36°N to 48.5°N and from 68°W to 89°W; this area includes much of the Great Lakes region, Ohio Valley, St. Lawrence Valley, central and northern Appalachians, and U.S. northeastern seaboard. One of four surface geostrophic wind-speed classes was also assigned to each grid cell for each of the 1,826 study days. A variety of statistics have been calculated for this climatological data set, including joint frequency tables, category persistence probabilities, and category transition probabilities. A comparison of statistics for different grid squares, rows, or columns reveals mesoscale variations in the synoptic climatology with latitude, longitude, and season. For instance, the seasonal movement of the polar front and its mean position over this region can be identified, as can the northward and westward extent of the Bermuda High. Climatic modifications due to the presence of the Great Lakes and the Appalachian Mountains are also evident in the statistics. This climatology was prepared in order to determine the frequency of occurrence of synoptic conditions which favor the generation of terrain-forced mesoscale circulations such as lake-land breezes and mountain-valley winds, as part of a larger investigation into the impact of mesoscale atmospheric circulations on the long-range transport of air pollutants. However, this climatology can also be applied to such areas as air pollution potential evaluations, wind energy 'prospecting', and environmental impact assessments.


December 11, 1990.
Includes bibliographical references (pages 98-101).

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Synoptic climatology -- East (U.S.)
Mesometeorology -- East (U.S.)
Weather forecasting -- East (U.S.)
Synoptic climatology -- North America
Mesometeorology -- North America
Weather forecasting -- North America


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