Extreme sea levels at Rapa Nui (Easter Island) during intense atmospheric rivers

Matías Carvajal, Patricio Winckler, René Garreaud, Felipe Igualt, Manuel Contreras-López, Pamela Averil, Marco Cisternas, Alejandra Gubler, Wolfgang A. Breuer

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

In addition to the tsunami hazard posed by distant great earthquakes, Rapa Nui (Easter Island), in the Southeast Pacific Ocean, is exposed to frequent and intense coastal storms. Here, we use sea-level records and field surveys guided by video and photographic footage to show that extreme sea levels at Rapa Nui occur much more frequent than previously thought and thus constitute an unrecognized hazard to the inland’s maritime supply chain. We found that extreme sea-level events, including the two most extreme (March 5th and May 5th, 2020) in our 17-month-long analyzed period (from January 1st, 2019, to May 31st, 2020), resulted from constructive superpositions of seiches on the shelf, storm surges and high tides. By further analyzing time series of atmospheric and wind-generated wave data, we conclude that these extreme sea levels are ultimately driven by the breaking of large waves near the coastline (i.e., wave setup), with lesser contribution of barometric setup and even less of wind setup. We also propose that these large waves were mainly generated from strong, long-lasting, NW winds associated with intense atmospheric rivers (long, narrow regions in the atmosphere that transport abundant water vapor) passing over Rapa Nui. Given that the intensity of atmospheric rivers and sea level are thought to increase as climate changes, a deeper understanding of the relation between meteorological and oceanographic processes at Rapa Nui is strongly needed.

Original languageEnglish
Pages (from-to)1619-1637
Number of pages19
JournalNatural Hazards
Volume106
Issue number2
DOIs
StatePublished - Mar 2021
Externally publishedYes

Keywords

  • Atmospheric rivers
  • Easter Island
  • Integrated water vapor
  • Meteotsunamis
  • Rapa Nui
  • Sea level
  • Seiches
  • Shelf resonance
  • Storm surge

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