The Relative Oceanic Niño Index (RONI) is a tool used for comparing current and historical El Niño and La Niña events, as cited in the NOAA/NCEI ENSO SST Indicators Guide.
Notes on verification
Core claim about RONI's purpose is strongly corroborated by NOAA CPC's official announcement and the peer-reviewed L'Heureux et al. 2024 paper. However, the specific citation to a 'NOAA/NCEI ENSO SST Indicators Guide' document title could not be independently verified, though NCEI does host related ENSO SST resources.
Sources
- El Niño Today | El Nino Theme Page - A comprehensive Resource (pmel.noaa.gov)
- https://ggweather.posthaven.com/relative-oceanic-nino-index-roni-replacing-oni-as-enso-metric (ggweather.posthaven.com)
- 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)