Diversity in the Persistence of El Niño Events Over the Last Millennium. Issue 18 (21st September 2021)

• Record Type: Journal Article
• Authors: Sanchez, Sara C.; Karnauskas, Kristopher B.
• Is Part Of: Geophysical research letters. Volume 48:Issue 18(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-09-21
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2021GL093698
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The El Niño Southern Oscillation (ENSO) is a mode of internal climate variability with far‐reaching impacts. Here, we consider an important aspect of ENSO behavior: the diversity in the persistence of El Niño events. We examine the occurrence of multi‐year El Niño events in instrumental observations, a suite of global climate model simulations of the last millennium, and paleoclimate archives. We find evidence of multi‐year El Niño events in all data sources considered, with a wide range of variability in the frequency of such events across and within the individual sources. Although scarce over the relatively brief satellite era, multi‐year El Niño events are often associated with the warmest El Niño events in observations and most models. Furthermore, we show that multi‐year El Niño events augment the persistence of associated hydroclimate anomalies, which may compound the impacts on vulnerable economies and ecosystems within and beyond the tropical Pacific sector. Plain Language Summary: A typical El Niño event spans a single year, but on occasion, an El Niño event can span multiple, consecutive years. Here we investigate unusually persistent El Niño events in instrumental observations, 11 different climate models that simulate the climate of the last millennium, and in temperature sensitive paleoarchives from the central equatorial Pacific. Multi‐year El Niño events are found in observations, all models, and paleoarchives over the course of the last millennium, albeit with much diversity between the various simulations and observations. In an individual product or simulation, there are oftentimes centuries with many multi‐year El Niño events followed by centuries with few multi‐year events. Many of the largest El Niño events found in observations, climate model simulations, and paleoarchives feature this unusual persistence. Additionally, these multi‐year events can cause persistent impacts in global precipitation and surface temperatures. Key Points: We find consistent evidence of multi‐year El Niño events in instrumental observations, paleoclimate archives, and global climate models The characteristics of these events vary at low frequencies. At centennial timescales, such variation is indistinguishable from random noise Multi‐year El Niños are often among the largest events, with implications for global precipitation and temperature impacts