ENSO‐Driven Ocean Extremes and Their Ecosystem Impacts

Marine Heatwaves

“…Remotely sensed SSTs indicate that MHW frequencies range from approximately one to three events per year on average (Figure 6a). In the eastern tropical Pacific, however, El Niño-Southern Oscillation (ENSO) events manifest as individual, long-lasting MHWs (Holbrook et al 2020a). Hot spots of high MHW intensity (Figure 6b) occur in regions of large SST variability (Figure 6e), including the five western boundary current extension regions (Chen et al 2014, the central and eastern equatorial Pacific Ocean (Echevin et al 2018), and eastern boundary current regions (Rouault et al 2007).…”

“…Hot spots of high MHW intensity (Figure 6b) occur in regions of large SST variability (Figure 6e), including the five western boundary current extension regions (Chen et al 2014, the central and eastern equatorial Pacific Ocean (Echevin et al 2018), and eastern boundary current regions (Rouault et al 2007). Typical MHW durations (Figure 6c) are longest in the eastern tropical Pacific, a region dominated by ENSO SST variability with an average duration of up to 60 days (Holbrook et al 2020a), and shortest over other tropical regions, typically 5-10 days. In the extratropics, MHW durations are more uniformly 10-15 days, with the northeast and southeast Pacific Ocean being exceptions (up to 30-day mean durations; Di Lorenzo & Mantua 2016).…”

“…ENSO is the dominant mode of interannual climate variability across the globe (e.g., McPhaden et al 2006). It is also a leading cause of MHW occurrences globally (Oliver et al 2018a), with key influences and impacts in the Indo-Pacific (Holbrook et al 2019(Holbrook et al , 2020a and more distant links to the Atlantic and Southern Oceans (Holbrook et al 2019). Coupled air-sea interactions in the tropical Pacific are related to large shifts in SST and directly affect MHW www.annualreviews.org • Marine Heatwaves 20.17…”

A catalogue of marine heatwave metrics and trends for the Australian region

“…Specifically, MHW predictability is considered on temporal scales ranging from short-term weather (atmospheric blocking and oceanic eddies), to multiyear-to-decadal (via oceanic Rossby wave teleconnections), and centennial (climate change) time scales. Modes of climate variability, in particular ENSO, play an important role in modulating MHW likelihoods around the world (Scannell et al 2016;Oliver et al 2018a;Holbrook et al 2019) with impacts on marine ecosystems (Holbrook et al 2020a). The importance of ocean mixed layer depths and heat content (e.g.…”

Diversity in the Persistence of El Niño Events Over the Last Millennium

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The El Niño-Southern Oscillation (ENSO) is the dominant mode of interannual variability on the planet, involving powerful feedbacks between the tropical Pacific Ocean and overlying atmospheric (Walker) circulation (Bjerknes, 1969). The ENSO system oscillates between two phases, a warm El Niño state and a cool La Niña state; both are capable of exerting considerable influence on global anomalies of precipitation and surface temperatures (Ropelewski & Halpert, 1987), which threaten vulnerable communities and ecosystems around the globe (Cane et al, 1994;Goddard & Gershunov, 2020;Holbrook et al, 2020). Much of ENSO research in recent decades has focused on the diversity of different characteristics of ENSO events (Capotondi et al, 2015) especially in spatial pattern, amplitude, and frequency.

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