The NOAA/NCEI ENSO SST Indicators Guide cites the Relative Oceanic Niño Index (RONI) as a comparison tool for El Niño and La Niña events.
Notes on verification
Confirmed by primary NOAA/PMEL source text and corroborated by multiple independent NOAA/NWS/CPC documents describing RONI's official role in ENSO monitoring.
Sources
- El Niño Today | El Nino Theme Page - A comprehensive Resource (pmel.noaa.gov)
- https://bmcnoldy.earth.miami.edu/tropics/roni/ (bmcnoldy.earth.miami.edu)
- https://weather.gov/media/notification/pdf_2026/pns26-05_Relative_ONI.pdf (weather.gov)
- https://journals.ametsoc.org/view/journals/clim/37/4/JCLI-D-23-0406.1.xml (journals.ametsoc.org)
- https://www.drought.gov/news/new-noaa-el-nino-southern-oscillation-index-supports-drought-early-warning-2026-03-11 (drought.gov)
- https://www.climate.us/news-features/understanding-climate/climate-variability-relative-oceanic-nino-index (climate.us)