92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Wednesday, 25 January 2012: 8:30 AM
Atmospheric Circulation Patterns and Physical Processes Associated with Temperature Extremes Over North America
Room 354 (New Orleans Convention Center )
Paul C. Loikith, Rutgers University, New Brunswick, NJ; and A. J. Broccoli

Evidence suggests that observed changes in temperature extremes may be influenced by anthropogenic climate change with further and more drastic changes projected by the end of this century. To better anticipate these changes, a comprehensive understanding of the physical processes associated with extreme temperatures is necessary. We have identified the most important atmospheric circulation patterns and physical mechanisms associated with daily temperature extremes over North America. Circulation patterns associated with daily temperature extremes are found to be smaller in spatial scale than well-known modes of low-frequency climate variability (such as the PNA, NAO, etc.). These patterns vary based on latitude, season, and proximity to geographic and topographic features, such as major mountain ranges, that allow for unique circulation patterns to develop in association with extreme events. Such features have a greater impact on defining surface circulation patterns than those aloft where spatial variability in the patterns across the continent is less. There is some indication of land surface-atmosphere coupling associated with extreme temperature days; however it is unclear whether these processes play a causative role in temperature extremes. We will use the results from this work to evaluate the ability of climate models to simulate the large-scale circulation anomalies associated with extreme events in the current climate and future global warming simulations.

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