HR: 0800h
AN: U41C-0623    [Abstracts]
TI: Attribution of Precipitation Changes in the Mackenzie and Yukon Watersheds During the Second Half of the 20th Century
AU: * Cassano, J J
EM: John.Cassano@colorado.edu
AF: Cooperative Institute for Research in Environmental Sciences, UCB 216 University of Colorado, Boulder, CO 80309, United States
AU: * Cassano, J J
EM: John.Cassano@colorado.edu
AF: Department of Atmospheric and Oceanic Sciences, UCB 311 University of Colorado, Boulder, CO 80309, United States
AU: Cassano, E N
EM: ecassano@cires.colorado.edu
AF: Cooperative Institute for Research in Environmental Sciences, UCB 216 University of Colorado, Boulder, CO 80309, United States
AB: The method of self-organizing maps (SOMs) is used to investigate changes in precipitation in northwestern North America including the Mackenzie and Yukon watersheds over the time period of 1957-2002. The SOM is used to create a synoptic climatology of 35 unique sea level pressure patterns for this region. The changes in frequency of occurrence for each of these patterns over the time period of study has been determined and the patterns are then related to precipitation in this region. Changes in precipitation are attributed to dynamic (circulation changes), thermodynamic (atmospheric moisture content changes), or a combination of these two mechanisms. Of particular interest are changes in precipitation that occurred after the climatic shift of 1976. In addition, attribution of precipitation changes are also studied in the context of changes in large scale climate indices (AO, PDO). This analysis has been performed over the time period of study to determine if the forcing for precipitation has changed over the analysis period.
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 3349 Polar meteorology
DE: 3354 Precipitation (1854)
DE: 3364 Synoptic-scale meteorology
SC: Union [U]
MN: 2007 Fall Meeting