Climate Timeseries
TPI (IPO) Tripole Index for the Interdecadal Pacific Oscillation
| 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. It is a measure of interdecadal variability in the Pacific. The map to the right shows the correlations of the low-pass index TPI with filtered HadISST2.1(composite of 10 realisations). Versions have been calculated from these SST datasets: NOAA ERSST: V5, the HadISST1.1, and COBE-SST. We have removed the ERSST V4 and V3b as those datasets are no longer being updated |  With filtered HadISST2.1(composite of 10 realisations), similarly to Henley et al (2015) |
- Time Interval: Monthly
- Time Coverage: 1854 to near present (NOAA ERSST: V5)
- Time Coverage: 1870 to 2010 (HadISST1.1)
- Time Coverage: 1891 to near present (COBE)
- Update Status: monthly
- TPI (from NOAA ERSST V5) unfiltered: Standard PSL Format (What is standard format?)
- TPI (from NOAA ERSST V5) filtered: Standard PSL Format (What is standard format?)
- TPI (from NOAA ERSST V5) unfiltered 1981-2010 climo: Standard PSL Format (What is standard format?)
- TPI (from NOAA ERSST V5) filtered 1981-2010 climo: Standard PSL Format (What is standard format?)
- TPI (from HADISST1.1) unfiltered: Standard PSL Format (What is standard format?)
- TPI (from HADISST1.1) filtered: Standard PSL Format (What is standard format?)
- TPI (from COBE) unfiltered: Standard PSL Format (What is standard format?)
- TPI (from COBE) filtered: Standard PSL Format (What is standard format?)
- Timeseries are calculated at NOAA/ESRL PSL
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. The regions used to calculate the index shown in the map above and are:
You can download an NCL script that shows how the time-series are calculated (also get writets.ncl). If your SST data has a different format, you will need to adjust the code.
References and Citation:
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
The climatology time period is now Jan 1971 to Jan 2000.
Region 2: 10°S–10°N, 170°E–90°W
Region 3: 50°S–15°S, 150°E–160°W
You can download an NCL script that shows how the time-series are calculated (also get writets.ncl). If your SST data has a different format, you will need to adjust the code.
- Henley, B.J., Gergis, J., Karoly, D.J., Power, S.B., Kennedy, J., Folland, C.K., (2015). A Tripole Index for the Interdecadal Pacific Oscillation. Clim. Dyn. 45 (11–12), 3077–3090, http://dx.doi.org/10.1007/s00382-015-2525-1.
- If you use this data, the creators request it be cited as:
Henley, B.J., Gergis, J., Karoly, D.J., Power, S.B., Kennedy, J., & Folland, C.K. (2015). A Tripole Index for the Interdecadal Pacific Oscillation. Climate Dynamics, 45(11-12), 3077-3090.http://dx.doi.org/10.1007/s00382-015-2525-1 . Accessed on MM DD YYYY at "/data/timeseries/IPOTPI".