HR: 1340h
AN: A13E-1608    [Abstracts]
TI: The Effect of Sea-Ice Extent on storm activity in the North Pacific/Western Arctic
AU: * Mesquita, M d
EM: mmeclimate@mac.com
AF: University of Alaska Fairbanks, P.O. Box 757340, Fairbanks, AK 99775, United States
AU: * Mesquita, M d
EM: mmeclimate@mac.com
AF: International Arctic Research Center, 930 Koyukuk Dr., Fairbanks, AK 99775, United States
AU: King, M P
EM: mpking@iarc.uaf.edu
AF: International Arctic Research Center, 930 Koyukuk Dr., Fairbanks, AK 99775, United States
AU: King, M P
EM: mpking@iarc.uaf.edu
AF: Arctic Region Supercomputing Center, P.O. Box 756020, Fairbanks, AK 99775, United States
AU: Atkinson, D E
EM: datkinson@iarc.uaf.edu
AF: University of Alaska Fairbanks, P.O. Box 757340, Fairbanks, AK 99775, United States
AU: Atkinson, D E
EM: datkinson@iarc.uaf.edu
AF: International Arctic Research Center, 930 Koyukuk Dr., Fairbanks, AK 99775, United States
AB: High-latitude storm activity plays important roles at various time and space scales, ranging from the local scale, with for example, severe erosion suffered by coastal margins in Alaska and other arctic regions, to the continental scale, where for example storm corridor position and strength strongly affect the exchange of moisture and heat between the Arctic and the lower latitudes. Sea-ice, specifically the location of the ice edge, plays an important role in the location of storm tracks as well. Its presence can impede storm progression into the Arctic by creating a cold friction zone over which storms lose energy. At the ice edge is often found a strong baroclinic zone which can enhance storm activity by both strengthening storms and by acting to preferential guide their trajectory. The extent of sea-ice varies considerably from year to year and has exhibited distinct decreasing trends over time with attendant impacts on storm track location. This paper studies the effects of sea-ice edge position on the location of storm tracks in the western Arctic (Bering and Chukchi Seas) by examining the response of storms during the active months of October and November under the influence of three different sea-ice scenarios: two historical for the 1952 - 2002 period, and one projected for the year 2050. The studies are conducted using SPEEDY, an Atmospheric Global Circulation Model (Molteni, 2003), with a spectral resolution of T30 (approximately 3.75° horizontal resolution). The sea ice forcing fields for the following three scenarios are based on datasets from the Met Office (HadISST 1.1) and the Arctic Climate Impact Assessment: 1) the maximum ice extent; 2) the minimum ice extent, and 3) the minimum projected sea-ice edge for the next 50 years using the ACIA 5-model composite data. Storm track response is investigated using metrics that include variance of the 500 mb geopotential height field and potential vorticity maxima. The impact of these storm activity variations on poleward heat and moisture transfer are also examined.
DE: 0545 Modeling (4255)
DE: 1620 Climate dynamics (0429, 3309)
DE: 1626 Global climate models (3337, 4928)
DE: 3309 Climatology (1616, 1620, 3305, 4215, 8408)
DE: 3319 General circulation (1223)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting