On the variability and predictability of daily temperatures in the Arctic

Daily maximum and minimum temperature data front 54 stations in Alaska and northern Canada are used to evaluate temporal changes in the variance and autocorrelation of the daily anomalies front 1950-2000. To the extent that the variance and autocorrelation capture variability and anomaly persistence, the results provide a quantitative counterpart to reports from Arctic communities that weather is becoming increasingly variable and unpredictable. Although the results show indications of increased variance at some locations in some seasons, at least as many other stations show no such trends or show trends opposite to the hypothesized increase in variance and decrease in persistence of temperature anomalies. These findings apply to northern subsets as well as to the entire sample of stations. However, the frequency of extreme anomalies relative to single-month means does show a modest but steady increase front the 1950s to the 1990s. The absence of a more generally apparent increase in variance and decrease in predictability is most likely attributable to either: (a) the choice of temperature as a measure of weather, (b) our use of simple statistical measures of variability and persistence, or (c) the role of technological and social changes in shaping perceptions of weather variability and predictability.