Influence of Ocean Surface Conditions on Regional Climate of the Northern North Atlantic.

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The proposed research will carry out a modeling and observationally-based investigation of the impact of northern Atlantic sea surface temperature anomalies (SSTAs) on the climate and atmo-spheric circulation variability over a region extending from Baffin Island to the Norwegian Sea. Mesoscale model simulations are to be performed of known, high persistent, negative SSTAs that occurred from October 1982 to September 1984 to the west of Greenland and from October 1967 to September 1969 east of Greenland. Each of these events, which are potentially associated with decadal-period ocean SSTAs, will use a modeling approach to evaluate the oceanic impact on regional temperatures, precipitation and atmospheric circulation variability including storm track shifts. The model results will be compared with SSTA sensitivity experiments in which the ocean has a positive warm anomaly during the same periods. A third model sensitivity study will employ month-long simulations for winter and summer to investigate the roles of SSTAs on the movement of storms across the Norwegian Sea and into the Arctic, and the simultaneous tendency for the subpolar low to lie far east of Iceland. Accompanying observational analyses will focus on evaluating the climatic impacts of a decadally varying warm SST pool in the northern Atlantic, especially from 1920-1940, as well as other cold events prior to 1970. By examining the effects of the anomalies in regions east of Greenland and near Labrador, the research hopes to determine whether the previously identified extremely persistent anomalies in Davis Strait are unique or common. Rotated principal component analyses will be used in an effort to determine links dur-ing all seasons between northern Atlantic SSTAs and Atlantic storm tracks. Storm track data will be used to further evaluate links between the North Atlantic and Arctic oscillations, as well as to assess how eastward storm track shifts impact sea ice transport. The end result is planned to be a comprehensive evaluation of the SST impact on Atlantic Arctic climate and circulation variability and an assessment of the dominant Atlantic storm tracks that impact the Atlantic and Arctic basins. The research will also allow an estimate of the predictability of cyclone activity anoma-lies in the northern North Atlantic. These results will contribute to our understanding of high lati-tude climate and ocean-atmosphere interactions within the context of the large changes that are at present impacting the northern Atlantic and Arctic regions.