Fig. 1. a) Mean winter and b) spring surface air temperature anomalies in St. Paul, Pribilof Islands, c) winter and d) spring Bering Sea pressure index. The winter months are December through March and spring months are April through June. The base period for calculating anomalies is 1961-2000. The stepwise functions (orange lines) characterize regime shifts in the level of fluctuations of the variables. Shift points were calculated using the STARS method (Rodionov 2004), with the cutoff length of 10 years and significance level of 0.2.