21st Conference on Climate Variability and Change


A GCM-based analysis of circulation controls on del18O in the southwest Yukon, Canada: implications for climate reconstructions in the region

Robert Field, University of Toronto, Toronto, ON, Canada; and G. W. K. Moore and G. Holdsworth

To improve our understanding of paleoclimatic records in the southwest Yukon, we examined controls on precipitation del18O using an isotopically-equipped general circulation model. Our results show that, particularly during the cool-season, elevated del18O is associated with a deeper Aleutian Low and stronger southerly moisture flow, while lower del18O is associated with the opposite meteorological conditions. These results suggest that the large mid-19th century shift towards lower del18O values seen in paleoclimate records from the region was associated with a shift towards a weaker Aleutian Low. While in disagreement with a previous interpretation of this shift, it is consistent with records of glacial advance and tree-ring growth during the same period, and observational studies of Aleutian Low controls on temperature and precipitation in the region.

Poster Session 3, Global dynamics and prediction - posters
Tuesday, 13 January 2009, 9:45 AM-11:00 AM, Hall 5

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