The Southern California Temperature Index data is available as a netCDF file (SCTI.nc).
You are welcome to download and use these figures and the associated data. If you do so please refer to DOI: 10.21238/S8SPRAY7292
The Southern California Temperature Index (SCTI) is derived from the sea water temperature records of the California Underwater Glider Network (CUGN), a collection of over a decade of Spray underwater glider measurements. CUGN provides the mean field and the annual cycle, which subtracted from the observed temperature gives the interannual anomaly of the sea water temperature near the California Coast (illustraded above).
The Southern California Temperature Index represents a smoothed temperature anomaly variability near the coast of California, which results from two steps: First it is obtained the average of the interannual anomaly temperature along the line 90, between the coast up to 200km offshore at 50m depth, resulting in a timeseries; Second, that timeseries is smoothed by a low-pass filter with half-power cutoff on 90 days.
The Oceanic Niño Index is a low-pass filtered of Niño 3.4 index, which was obtainned from the Climate Prediction Center of the National Oceanic and Atmospheric Administration (NOAA).