Persistent anomalies of the Southern Hemisphere circulation

The persistent features of large anomalies have been examined and the locations of blocking in the Southern Hemisphere were determined. The data set used here contains daily maps of 500 mb geopotential heights for 100 months (June 1, 1972 to Nov. 30, 1980) covering from 10S to 90S. The seasonal cycle was defined as a 8 year mean and the 8th (annual) and 16th (semiannual) Fourier components of the time series at each grid point. Anomalies were defined as the difference between the total field and the seasonal cycle for each grid point.