Skill of Seasonal Climate Forecasts in Canada Using Canonical Correlation Analysis

Abstract

Abstract An empirical system for forecasting 3-month mean surface temperature T and total precipitation P for Canada—canonical correlation analysis (CCA)—has been developed using the 1956–90 data period. The levels and sources of predictive skill have been estimated for all seasons at lead times of up to one year, using a cross-validation design. The predictor fields are quasi-global sea surface temperature (SST), Northern Hemisphere 500-mb geopotential height, and for T forecasts prior values of T itself. Four consecutive 3-month predictor periods are used to detect evolving as well as steady-state conditions in the predictor fields. While forecast skills are modest for much of the year, winter and spring skills for T forecasts at a 3-month lead time are both highly statistically field significant and good enough to be beneficial to appropriate users. These forecasts average a 0.3–0.4 correlation skill nationwide and greater than 0.6 in the southeastern prairies. Forecast skill for P averages a lower but...