21st Conference on Climate Variability and Change


Observed and Modeled Surface-based Temperature Inversions in Alaska: Trends and Variability

Stefanie M. Bourne, Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK; and U. S. Bhatt, J. Zhang, and R. Thoman

Alaska surface-based temperature inversion parameters (inversion depth, temperature difference, strength and frequency) were calculated using radiosonde observations for Fairbanks, McGrath, Anchorage, and Barrow. Trends and variability were examined for 1957-2008. At all sites, surface temperatures show increasing trends, while inversion depth and temperature difference are decreasing. Inversion strength shows increasing trends in Interior Alaska, but decreasing trends along the coast. Inversion parameters display similar interannual variability for all sites and show statistically significant correlation to large-scale climate variability.

Alaska surface-based inversions were evaluated in a hierarchy of model simulations. The global model is not able to capture key inversion characteristics. However, dynamically downscaled regional models can better simulate variability of inversion parameters, but the means display biases which are easily correctable. Inversions, evaluated in a downscaled A1B future scenario, show a general warming of the entire air column and an overall decrease in inversion depth and temperature difference.

Session 9B, Observed changes in climate - II
Wednesday, 14 January 2009, 10:30 AM-12:00 PM, Room 129B

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