Shayne Mcgregor

Shayne Mcgregor
Monash University (Australia) · School of Earth, Atmosphere and Environment

PhD

About

90
Publications
33,865
Reads
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6,088
Citations
Citations since 2016
51 Research Items
4984 Citations
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201620172018201920202021202202004006008001,000
201620172018201920202021202202004006008001,000
Additional affiliations
August 2015 - present
December 2010 - August 2015
UNSW Sydney
Position
  • Research Associate
January 2009 - December 2010
University of Hawaiʻi at Mānoa
Position
  • PostDoc Position

Publications

Publications (90)
Article
Full-text available
Plain Language Summary From early 1990s to late 2010, the equatorial trade winds strengthened in the Pacific Ocean. This coincided with a rapid rise in sea level in the western tropical Pacific and a slowdown in global surface temperature warming. This long‐term change in the Pacific had a large impact, but ocean‐atmosphere models cannot produce a...
Article
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Plain Language Summary The El Nino–Southern Oscillation (ENSO) has far reaching impacts through atmospheric teleconnections, which make it a prominent driver of global interannual climate variability. As such, whether and how these teleconnections may change due to projected future climate change remains a topic of high societal relevance. Here, EN...
Article
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This study examines the relationship between low decadal mean precipitation and monthly-scale wet and dry extremes over the global land area. We characterise how precipitation distributions change on decadal timescales, and how these changes are linked to seasonal scale drought. The relationship between decadal mean precipitation and extremes is as...
Article
This study utilizes observations and a series of idealized experiments to explore whether eastern Pacific (EP)- and central Pacific (CP)-type El Niño–Southern Oscillation (ENSO) events produce surface wind stress responses with distinct spatial structures. We find that the meridionally broader sea surface temperatures (SSTs) during CP events lead t...
Article
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Using the new Australian National Collection of Homogenized Observations of Relative Sea Level (ANCHORS) dataset, we assess trends in Australian relative sea levels over recent decades and subsequent coastal flooding impacts. We estimate a gauge average rate of mean sea level rise over the 1966–2019 period of 1.94 mm/yr with local variations around...
Article
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Plain Language Summary It is widely accepted that Tropical modes of variability, such as El Niño–Southern Oscillation (ENSO) and the IOD, play a crucial role in modulating the year‐to‐year variability in Australian precipitation and extreme weather events, including conditions favorable to record‐breaking bushfire events such as the catastrophic 20...
Article
A decades-long affair Decadal climate variability and change affects nearly every aspect of our world, including weather, agriculture, ecosystems, and the economy. Predicting its expression is thus of critical importance on multiple fronts. Power et al . review what is known about tropical Pacific decadal climate variability and change, the degree...
Article
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Past attempts to reconstruct the Southern Annular Mode (SAM) using paleo-archives have resulted in records which can differ significantly from one another prior to the window over which the proxies are calibrated. This study attempts to quantify not only the skill with which we may expect to reconstruct the SAM but also to assess the contribution o...
Article
Originating in the equatorial Pacific, the El Niño–Southern Oscillation (ENSO) has highly consequential global impacts, motivating the need to understand its responses to anthropogenic warming. In this Review, we synthesize advances in observed and projected changes of multiple aspects of ENSO, including the processes behind such changes. As in pre...
Chapter
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This Annex describes the fundamental features of the main modes of large-scale climate variability assessed across chapters in the AR6 WGI report. Modes are defined as recurrent space-time structures of variability of the climate system with intrinsic spatial patterns, seasonality and timescales. They can arise through the dynamical characteristics...
Chapter
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The evidence for human influence on recent climate change strengthened from the IPCC Second Assessment Report to the IPCC Fifth Assessment Report, and is now even stronger in this asessment. The IPCC Second Assessment Report (1995) concluded ‘the balance of evidence suggests that there is a discernible human influence on global climate’. In subsequ...
Article
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El Niño–Southern Oscillation (ENSO) is the dominant mode of interannual climate variability on the planet, with far-reaching global impacts. It is therefore key to evaluate ENSO simulations in state-of-the-art numerical models used to study past, present, and future climate. Recently, the Pacific Region Panel of the International Climate and Ocean:...
Article
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Understanding mechanisms of tropical Pacific decadal variability (TPDV) is of high importance for differentiating between natural climate variability and human induced climate change as this region sustains strong global teleconnections. Here, we use an ocean general circulation model along with a Lagrangian tracer simulator to investigate the adve...
Article
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Decadal climate prediction presumes there are decadal-timescale processes and mechanisms that, if initialized properly in models, potentially provide predictive skill more than one or two years into the future. Candidate mechanisms involve Pacific decadal variability and Atlantic multidecadal variability, elements of which involve slow fluctuations...
Conference Paper
Full-text available
The evidence for human influence on recent climate change strengthened from the IPCC Second Assessment Report to the IPCC Fifth Assessment Report, and is now even stronger in this assessment. The IPCC Second Assessment Report (1995) concluded ‘the balance of evidence suggests that there is a discernible human influence on global climate’. In subseq...
Article
Full-text available
A robust eastern Pacific surface temperature cooling trend was evident between ~1990–2013 that was considered as a pronounced contributor to the global surface warming slowdown. The majority of current climate models failed to reproduce this Pacific cooling trend, which is at least partly due to the underrepresentation of trans-basin teleconnection...
Chapter
The response of the El Niño–Southern Oscillation (ENSO) to tropical and extratropical volcanic eruptions has important worldwide implications for volcanically driven risk estimates. While there have been many studies on this subject using observations, paleoclimate archives, and model simulations, a comprehensive review of ENSO response to tropical...
Article
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This study demonstrates that the generalization that strong anomalous equatorial Pacific westerly (easterly) winds during El Niño (La Niña) events displays strong adjusted warm water volume (WWV) discharges (recharges) is often incorrect. Using ocean model simulations, we categorize the oceanic adjusted responses to strong anomalous equatorial wind...
Preprint
Full-text available
Past attempts to reconstruct the Southern Annular Mode (SAM) using paleo archives have resulted in records which can differ significantly from one another prior to the window over which the proxies are calibrated. This study attempts to quantify not only the skill with which we may expect to reconstruct the SAM, but also assess the contribution of...
Article
Full-text available
As global mean sea level (GMSL) continues to rise, thresholds corresponding to coastal inundation impacts are exceeded more frequently. This paper aims to relate sea‐level rise (SLR) observations and projections to their physical on‐the‐ground impacts. Using a large coastal city as an example, we show that in Sydney, Australia, frequencies of minor...
Article
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Despite the observed monotonic increase in greenhouse-gas concentrations, global mean temperature displays important decadal fluctuations typically attributed to both external forcing and internal variability. Here, we provide a robust quantification of the relative contributions of anthropogenic, natural, and internally-driven decadal variability...
Article
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The El Niño phase of the El Niño Southern Oscillation (ENSO) is typically associated with below‐average cool‐season rainfall in southeastern Australia (SEA). However, there is also large case‐to‐case variability on monthly time scales. Despite recent progress in understanding the links between remote climate drivers and this variability, the underl...
Article
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As the dominant driver of interannual climate variability globally, any changes in the remote impacts of the El Niño-Southern Oscillation (ENSO) due to climate change are of considerable importance. Here we assess whether climate models from Phase 5 of the Coupled Model Intercomparison Project (CMIP5) project robust changes in ENSO’s regional tempe...
Article
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The shallow subtropical cells (STCs) in the Pacific Ocean are thought to modulate the background state that the El Niño‐Southern Oscillation (ENSO) operates in. This modulation is proposed to impact the frequency and intensity of ENSO events and their teleconnections. We use a high‐resolution ocean model to investigate the volume transports associa...
Article
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Plain Language Summary The sea surface temperature (SST) warming over the North Tropical Atlantic (NTA) region during boreal spring can induce a La Niña event during subsequent winter. This negative relationship is reported to be weakened due to global warming. This study emphasizes the role of Atlantic SST climatology on the weakening of the negat...
Article
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In this Review, the middle initial of author Kim M. Cobb was omitted. The original Review has been corrected online.
Article
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Tropical interconnections The El Niño–Southern Oscillation, which originates in the tropical Pacific, affects the rest of the world's tropics by perturbing global atmospheric circulation. Less appreciated than this influence is how the tropical Atlantic and Indian Oceans affect the Pacific. Cai et al. review what we know about these pantropical int...
Article
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Tropical instability waves (TIWs) are a major source of internally-generated oceanic variability in the equatorial Pacific Ocean. These non-linear phenomena play an important role in the sea surface temperature (SST) budget in a region critical for low-frequency modes of variability such as the El Niño–Southern Oscillation (ENSO). However, the dire...
Article
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The surface temperature response to greenhouse gas forcing displays a characteristic pattern of polar-amplified warming1–5, particularly in the Northern Hemisphere. However, the causes of this polar amplification are still debated. Some studies highlight the importance of surface-albedo feedback6–8, while others find larger contributions from longw...
Article
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El Niño and La Niña, the warm and cold phases of the El Niño Southern Oscillation (ENSO), cause significant year-to-year disruptions in global climate including in the atmosphere, oceans and cryosphere. Australia is one of the countries where its climate, including droughts and flooding rains, is highly sensitive to the temporal and spatial variati...
Article
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The recent 2015–16 El Niño was of comparable magnitude to the two previous record-breaking events in 1997–98 and 1982–83. To better understand how this event became an extreme event, we examine the underlying processes leading up to the peak of the event in comparison to those occurring in the 1997–98 and 1982–83 events. Differences in zonal wind s...
Article
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In the version of this Perspective originally published, affiliations 1 and 4 ware incorrect, and should have read: “¹Antarctic Climate & Ecosystems CRC, University of Tasmania, Hobart, Tasmania, Australia” and “⁴Centre for Water, Climate and Land (CWCL), University of Newcastle, Callaghan, NSW, Australia”. These have been corrected in the online v...
Article
El Niño events are characterized by surface warming of the tropical Pacific Ocean and weakening of equatorial trade winds that occur every few years. Such conditions are accompanied by changes in atmospheric and oceanic circulation, affecting global climate, marine and terrestrial ecosystems, fisheries and human activities. The alternation of warm...
Article
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The interaction of gradual climate trends and extreme weather events since the turn of the century has triggered complex and, in some cases, catastrophic ecological responses around the world. We illustrate this using Australian examples within a press-pulse framework. Despite the Australian biota being adapted to high natural climate variability,...
Article
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Pacific trade winds have displayed unprecedented strengthening in recent decades¹. This strengthening has been associated with east Pacific sea surface cooling² and the early twenty-first-century slowdown in global surface warming2,3, amongst a host of other substantial impacts4–9. Although some climate models produce the timing of these recently o...
Article
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The strengthening of the Pacific trade winds in recent decades has been unmatched in the observational record stretching back to the early twentieth century. This wind strengthening has been connected with numerous climate-related phenomena, including accelerated sea-level rise in the western Pacific, alterations to Indo-Pacific ocean currents, inc...
Article
A wind forced ocean model is used to decompose the equatorial Pacific warm water volume (WWV) between 1980-2016 into two components, the (i) adjusted wind response, which is found by letting the model evolve unforced for three months; and (ii) instantaneous wind response, which are the instantaneous WWV changes due to Ekman transports. Our results...
Article
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Potential changes to the El Niño-Southern Oscillation (ENSO) resulting from climate change may have far reaching impacts through atmospheric teleconnections. Here ENSO temperature and precipitation teleconnections between the historical and high-emission future simulations are compared in 40 models from phase 5 of the Coupled Model Intercomparison...
Article
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During the mature phase of El Niño-Southern Oscillation (ENSO) events there is a southward shift of anomalous zonal winds (SWS), which has been suggested to play a role in the seasonal phase locking of ENSO. Motivated by the fact that coupled climate models tend to underestimate this feature, this study examines the representation of the SWS in pha...
Article
Given the importance of tropical Pacific winds to global climate, it is interesting to examine differences in the mean and trend among various wind products, and their implications for ocean circulation. Past analysis has revealed that despite the assimilation of observational data, there remain large differences among reanalysis products. Thus, he...
Article
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The buildup of the warm water in the equatorial Pacific prior to an El Niño event is considered a necessary precondition for event development, while the event initiation is thought to be triggered by bursts of westerly wind. However, in contrast to the view that warm water slowly builds up years before an El Niño event, the volume of warm water in...
Article
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Near the end of the calendar year, when El Niño events typically reach their peak amplitude, there is a southward shift of the zonal wind anomalies, which were centred around the equator prior to the event peak. Previous studies have shown that ENSO’s anomalous wind stresses, including this southward shift, can be reconstructed with the two leading...
Article
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In this reply, the authors clarify the points made in the original paper in 2015 and show that issues raised in the comment by Li et al. are unsubstantiated. The main conclusions can be summarized as follows: 1) The time evolution of the anomalous low-level northwest Pacific anticyclone (NWP-AC) is largely caused by combination mode (C-mode) dynami...
Article
Climate models consistently project a substantial decrease in the Indonesian Throughflow (ITF) in response to enhanced greenhouse warming. On interannual timescales ITF changes are largely related to tropical Pacific wind variability. However, on the multi-decadal timescales investigated here we demonstrate that regional winds and associated change...
Article
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Reconstructions of the El Niño–Southern Oscillation (ENSO) ideally require high-quality, annually resolved and long-running palaeoclimate proxy records in the eastern tropical Pacific Ocean, located in ENSO's centre of action. However, to date, the palaeoclimate records that have been extracted in the region are short or temporally and spatially sp...
Article
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Unprecedented strengthening of Pacific trade winds has occurred in recent decades, while both the Indian and Atlantic Ocean surface temperatures warmed. Now a study suggests that the Atlantic Ocean warming is driving this Pacific trade wind strengthening and the warming of the Indian Ocean.
Article
Full-text available
Reconstructions of the El Niño-Southern Oscillation (ENSO) ideally require high-quality, annually-resolved and long-running paleoclimate proxy records in the eastern tropical Pacific Ocean, located in ENSO's centre-of-action. However, to date, the paleoclimate records that have been extracted in the region are short or temporally and spatially spor...
Article
The effects of large tropical volcanic eruptions on Indo-Pacific tropical variability are investigated using 122 historical ensemble members from CMIP5. Radiative forcing due to volcanic aerosols in the stratosphere is found to increase the likelihood of a model climatic response that projects onto both the El Niño-Southern Oscillation and the Indi...
Article
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The atmospheric teleconnections associated with the Eastern Pacific El Niño and El Niño Modoki events onto the tropical Atlantic Ocean are investigated. The Eastern Pacific El Niños drive significant warming of the tropical North Atlantic basin during boreal spring after its peak via the atmospheric bridge and tropospheric temperature mechanisms. H...
Article
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Nonlinear interactions between ENSO and the Western Pacific warm pool annual cycle generate an atmospheric combination mode (C-mode) of wind variability. We demonstrate that C-mode dynamics are responsible for the development of an anomalous low-level North-West Pacific anticyclone (NWP-AC) during El Niño events. The NWP-AC is embedded in a large-s...
Article
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This study evaluates the influence of various climate modes on sea level. The altimetry record has excellent spatial coverage but the limited length becomes an issue when evaluating low frequency variability in the presence of a trend. We use altimetry along with two ocean models to study how the relationship between sea surface height (SSH) in the...