Data:

· Indian Ocean Dipole (IOD_hist) and equatorial Pacific Warm Water Volume (WWV_hist) indices for the historical period spanning 1878-2001:

The IOD_hist index is based on a regression of Sea Surface Temperature (SST) observations (HadiSSTv1.1; Rayner et al. 2003) over the whole tropical Indian Ocean to reduce uncertainties on the DMI (Dipole Mode Index; Saji et al. 1999).

The WWV_hist index uses the temporal integral of equatorial Pacific zonal windstress from an atmospheric reanalysis (twentieth century atmospheric reanalysis version 2: 20CR; Compo et al. 2011) as a proxy of the oceanic WWV index (Meinen and McPhaden 2000).

The indices are interannual anomalies based on data over 1871-2008 (a high-pass filter was applied to remove periods higher than 7 years, i.e. decadal and long-term variations; thus after this filtering the time series are from 1878 to 2001). The annual files with the September-November (SON) average for each year are given in netcdf and ascii formats. See Izumo et al. 2013 for details on the construction and use of these historical indices.

IOD_hist index: [netcdf], [ascii]

WWV_hist index: [netcdf], [ascii]

Please cite associated references, if you use those data in your future work. Please contact us if you have any questions. Those data are for research purposes only.