SST indices derived from the NOAA ERSSTv3b (http://www.esrl.noaa.gov/psd/data/gridded/data.noaa.ersst.html) Domain for averaging SST: NINO34: 5S-5N, 120W-170W WPWP: 20S-20N, 90E-180 TAG: TNA - TSA TNA: 5N-20N, 60W-30W TSA: 20S-0, 30W-10E PDO: normalized PC1 of the EOF for N. Pacific SST (20N-65N, 125E-80W) For NINO34, WPWP, and TAG, the unit is degree C. SST indices from other sources: NOAA CPC Nino 3.4 SST index: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml PDO index: Univ. of Washington, Mantua et al. (1997) http://jisao.washington.edu/pdo/PDO.latest