Arctic Oscillation Index data

The University of Washington Joint Institute for the Study of the Atmosphere and Ocean (JISAO) offers an Arctic Oscillation (AO) Index dataset. The Arctic Oscillation (AO) is defined as the leading EOF of Northern Hemisphere sea-level pressure anomalies poleward of 20N, weighted by area (Thompson and Wallace, 1998). Digital values of the AO are available from Dave Thompson's anonymous ftp directory. Please send email to David ([email protected]) to let him know that you have obtained data from his directory. Thank you. Dave Thompson's ftp directory is linked here. The file entitled 'AO_index.README' describes the various AO time series available on the ftp directory: ftp://ftp.atmos.washington.edu/pub/jisao/davet/. More information is at: http://tao.atmos.washington.edu/data_sets/ao/ (source: Global Change Master Directory, http://gcmd.nasa.gov).