TPI (IPO) Tripole Index for the Interdecadal Pacific Oscillation
TPI (ISO) Dataset
http://www.esrl.noaa.gov/psd/data/times ... isst2.data
The index is based on the difference between the SSTA averaged over the central equatorial Pacific and the average of the SSTA in the Northwest and Southwest Pacific. Different SST datasets have been used to calculate the index (HadISST2.1, HadISST, NOAA ERSST V3b). The regions used to calculate the index shown in the map above and are:
Region 1: 25°N–45°N, 140°E–145°W
Region 2: 10°S–10°N, 170°E–90°W
Region 3: 50°S–15°S, 150°E–160°W
I just saw this recently.