Recent Trends In Laurentian Great Lakes Ice Cover

摘要: A 39-winter (1963-2001) record of annual maximum ice concentration (AMIC), the fraction lake surface area covered by each year, is analyzed for Great Lake. Lake Erie has largest median AMIC (94%) followed Lakes Superior (80%), Huron (63%), Michigan (33%), and Ontario (21%). The frequency distribution AMICs negatively skewed positively Ontario. Temporal spatial patterns typical extreme presented within context long-term average air temperatures bathymetry. variation spatially averaged with discrete depth ranges are discussed upper lower end range values. In general, decreases increasing a given winter. decrease in gradient depths was also observed an increase from winter 1983 to 1984. temporal trend supports hypothesis three cover regimes over past 39 winters. Approximately 44% highest quartile (10 highest) occurred during 6-winter period: 1977-1982 providing evidence higher regime this period relative 14 winters before them (1963- 1976) 19 after (1983-2001). Winter 1998 established new low extremes, 1998-2001 lowest on four five Lakes. These recent trends taken together noteworthy as they may be harbingers even 21st Century.