Cooperative Institute for Research in Environmental Sciences

Synoptic weather pattern controls on temperature in Alaska

Cassano, E.N., J.J. Cassano, and M. Nolan

2011, Journal of Geophysical Research - Atmospheres, 116, D11108, doi:10.1029/2010JD015341

Reanalysis data from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) and European Center for Medium-Range Weather Forecasts 40 year (ERA40) projects are used to relate large-scale synoptic circulation patterns to local weather at several locations across Alaska. These results are compared with available National Weather Service observations to demonstrate the utility of this method such that it can be applied in future work to locations where such observations are not available. The focus of this analysis is on surface observations of temperature and precipitation. The results from the two reanalysis datasets match well to each other and to the observations, temperature more so than precipitation. Synoptic patterns associated with warm/cold and wet/dry days at four National Weather Service stations representing different climate regions throughout Alaska are identified. In addition, a method to attribute a change in climate to circulation and non-circulation differences is applied to a known climate shift, the Pacific climate shift of 1976, which was associated with an increase in temperatures throughout Alaska. The results from this analysis show that general warming rather than changes in circulation is primarily responsible for the observed warming.