Climate Timeseries

TPI (IPO) Tripole Index for the Interdecadal Pacific Oscillation

Description:
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,V4,and V3b, as well as HadISST1.1 and COBE-SST.
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: V3b, V4, V5)
Time Coverage: 1870 to 2010 (HadISST1.1)
Time Coverage: 1891 to near present (COBE)
Update Status: monthly
Get Data: Source:
  • Timeseries are calculated at NOAA/ESRL PSD
Method:
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:
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.
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:
  • 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 "https://www.esrl.noaa.gov/psd/data/timeseries/IPOTPI".
Web Tools: Related Links: