Oceanic Niño Index (ONI) The ONI is based on SST departures from average in the Niño 3.4 region, and is a principal measure for monitoring, assessing, and predicting ENSO.
{"Image DocumentName": "Oceanic Ni\u00f1o Index (ONI)", "Image ImageDescription": "The ONI is based on SST departures from average in the Ni\u00f1o 3.4 region, and is a principal measure for monitoring, assessing, and predicting ENSO. Defined as the three-month running-mean SST departures in the Ni\u00f1o 3.4 region. Departures are based on a set of improved homogeneous historical SST analyses (Extended Reconstructed SST \u2013 ERSST.v3b). The SST reconstruction methodology is described in Smith et al., 2008, J. Climate, vol. 21, ) Used to place current events into a historical perspective. NOAA\u2019s operational definitions of El Ni\u00f1o and La Ni\u00f1a are keyed to the ONI index.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}