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. Index starts Jan1958, ends March 2000.
Units are arbitrary.
The Arctic Oscillation signature in the wintertime geopotential height and temperature fields. Postscript file of the manuscript and color figures Thompson, David W. J. and John. Annular modes in the extratropical circulation. Annular modes in the extratropical circulation.