Extreme rainfall activity in the Australian tropics reflects changes in the El Niño/Southern Oscillation over the last two millennia

Rhawn F. Denniston, Gabriele Villarini, Angelique N. Gonzales, Karl Heinz Wyrwoll, Victor J. Polyak, Caroline C. Ummenhofer, Matthew S. Lachniet, Alan D. Wanamaker, William F. Humphreys, David Woods, John Cugley

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

Assessing temporal variability in extreme rainfall events before the historical era is complicated by the sparsity of long-term "direct"storm proxies. Here we present a 2,200-y-long, accurate, and precisely dated record of cave flooding events from the northwest Australian tropics that we interpret, based on an integrated analysis of meteorological data and sediment layers within stalagmites, as representing a proxy for extreme rainfall events derived primarily from tropical cyclones (TCs) and secondarily from the regional summer monsoon. This time series reveals substantial multicentennial variability in extreme rainfall, with elevated occurrence rates characterizing the twentieth century, 850-1450 CE (Common Era), and 50-400 CE; reduced activity marks 1450-1650 CE and 500-850 CE. These trends are similar to reconstructed numbers of TCs in the North Atlantic and Caribbean basins, and they form temporal and spatial patterns best explained by secular changes in the dominant mode of the El Niño/Southern Oscillation (ENSO), the primary driver of modern TC variability. We thus attribute long-term shifts in cyclogenesis in both the central Australian and North Atlantic sectors over the past two millennia to entrenched El Niño or La Niña states of the tropical Pacific. The influence of ENSO on monsoon precipitation in this region of northwest Australia is muted, but ENSO-driven changes to the monsoon may have complemented changes to TC activity.

Original languageEnglish (US)
Pages (from-to)4576-4581
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume112
Issue number15
DOIs
StatePublished - Apr 14 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General

Keywords

  • Australia
  • ENSO
  • Flood
  • Stalagmite
  • Tropical cyclone

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