FIGURE E7. Standardized monthly amplitudes of
selcted Northern Hemisphere teleconnection patterns. The
teleconnection patterns are calculated from a Rotated Principal
Component Analysis (RPCA -10 Varimax spatial rotations) applied to
monthly 700-hPa standardized height anomalies between January 1964 -
July 1994. Ten patterns (or EOFs) are determined for each calendar
month by using all of the monthly height anomaly fields for the
three-month period centered on that month: [i.e., The July EOF
patterns are calculated based on the June, July, and August
standardized monthly anomalies]. The time series’ are calculated by
first projecting the standardized monthly anomalies onto the 10
leading EOFs corresponding to that month, and then solving for the
amplitudes of all ten patterns simultaneously using a Least-Squares
approach. In this approach the combination of the 10 resulting
amplitudes explains the maximum spatial structure of the observed
height anomaly field during the month. The monthly amplitudes are then
standardized for each calendar month independently. No value is
plotted for months in which the pattern does not appear as one of the
10 leading EOFs.
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