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Drivers and impacts of the most extreme marine heatwaves events

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posted on 2023-05-20, 20:33 authored by Sen Gupta, A, Thomsen, M, Benthuysen, JA, Hobday, AJ, Oliver, E, Alexander, LV, Burrows, MT, Donat, MG, Feng, M, Neil HolbrookNeil Holbrook, Perkins-Kirkpatrick, S, Rodrigues, RR, Scannell, HA, Taschetto, AS, Ummenhofer, CC, Wernberg, T, Smale, DA

Prolonged high-temperature extreme events in the ocean, marine heatwaves, can have severe and long-lasting impacts on marine ecosystems, fisheries and associated services. This study applies a marine heatwave framework to analyse a global sea surface temperature product and identify the most extreme events, based on their intensity, duration and spatial extent. Many of these events have yet to be described in terms of their physical attributes, generation mechanisms, or ecological impacts. Our synthesis identifies commonalities between marine heatwave characteristics and seasonality, links to the El Niño-Southern Oscillation, triggering processes and impacts on ocean productivity. The most intense events preferentially occur in summer, when climatological oceanic mixed layers are shallow and winds are weak, but at a time preceding climatological maximum sea surface temperatures. Most subtropical extreme marine heatwaves were triggered by persistent atmospheric high-pressure systems and anomalously weak wind speeds, associated with increased insolation, and reduced ocean heat losses. Furthermore, the most extreme events tended to coincide with reduced chlorophyll-a concentration at low and mid-latitudes. Understanding the importance of the oceanic background state, local and remote drivers and the ocean productivity response from past events are critical steps toward improving predictions of future marine heatwaves and their impacts.

History

Publication title

Scientific Reports

Volume

10

Article number

19359

Number

19359

Pagination

1-15

ISSN

2045-2322

Department/School

Institute for Marine and Antarctic Studies

Publisher

Nature Publishing Group

Place of publication

United Kingdom

Rights statement

Copyright 2020 The Authors. This article is licensed under a Creative Commons Attribution 4.0 International License

Repository Status

  • Open

Socio-economic Objectives

Climatological hazards (e.g. extreme temperatures, drought and wildfires); Climate variability (excl. social impacts)

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