Extended Abstract (1.3M)7B.3
Simulation of Arctic Storms
Zhenxia Long, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada; and W. Perrie and L. Zhang
In this study, a coupled regional climate model is implemented in west Canadian Arctic region, composed of the Canadian Regional Climate Model (CRCM) and Community Ice-Ocean Model (CIOM). Two Arctic storms were simulated with this coupled regional climate model. The first one originated in the Pacific in September 20, 1993 and moved northeastward into the Beaufort Sea. The lowest central pressure was reached when the storm passed over Tuktoyaktuk, with high winds developing rapidly and veering from the southeast to the west. Winds over 70km/h continued for 11 hours and peaked at 96km/h. The second storm, during August 9-11, 2000, originated in the Chukchi Sea. Its low pressure system reached a minimum central pressure of 994hPa as it moved rapidly into Beaufort Sea.
Compared to CMC (Canadian Meteorological Centre) reanalysis data, the coupled model gives a good reproduction of the main features of the two Arctic storms, such as the storm tracks. However, it slightly overestimates the intensity of the 1993 storm and underestimates the intensity of the 2000 storm. During the 2000 storm, surface temperatures along Canadian coast show strong diurnal variation, with the cold temperature first occurring near Greenland and then stretching into the Beaufort Sea. However, this diurnal variation is significantly underestimated in simulations that do not use CIOM, compared to NCEP reanalysis. No such diurnal variation has been found for the 1993 storm. In addition, the simulations show strong westward surface currents along Beaufort Sea coast during the two storms. The maximum responses at the Beaufort Sea occur when the storms move into Chukchi Sea where there exists a large expanse of open water, with the westward current dissipating when the storms move out of Beaufort Sea. Using the coupled model system, we discuss the impacts of the ocean surface and surface fluxes on the development of the two Arctic storms over Beaufort Sea.
Session 7B, High-latitude air-sea interaction
Tuesday, 13 January 2009, 3:30 PM-5:15 PM, Room 128B
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