All units are arbitrary. Figure available through this link. EOF is computed from data for all months, 1958-1997. Index values after 1997 are found by projecting the structure of the EOF onto monthly SLP anomalies. Index starts Jan1958, ends May 2000.
Units are arbitrary.
Found by projecting the AO pattern onto SLP anomalies back to Jan 1899. Index starts Jan 1899, ends May 2000. The second column is the index values. EOF is computed for data from all months, 1958-1997. Index values after 1997 are found by projecting the structure of the EOF onto monthly 850Z anomalies.