ORCID Profile
0000-0001-6533-5694
Current Organisations
University of New South Wales
,
Imperial College London
,
American Museum of Natural History
,
University of Melbourne
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Physical Oceanography | Climate Change Processes | Atmospheric Sciences | Oceanography | Glaciology | Meteorology
ANZSRC Socio-Economic Objective (SEO)
Climate Change Models | Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts) | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Atmospheric Processes and Dynamics | Climate Variability (excl. Social Impacts) | Expanding Knowledge in the Environmental Sciences | Expanding Knowledge in the Earth Sciences | Expanding Knowledge in the Information and Computing Sciences |
Related Links
Publications
Climate change affects multiple dimensions of well-being through impacts, information and policy responses
Publisher: Springer Science and Business Media LLC
Date: 16-11-2022
DOI: 10.1038/S41562-022-01467-8
Abstract: The consequences of climate change and responses to climate change interact with multiple dimensions of human well-being in ways that are emerging or invisible to decision makers. We examine how elements of well-being-health, safety, place, self and belonging-are at risk from climate change. We propose that the material impacts of a changing climate, discourses and information on future and present climate risks, and policy responses to climate change affect all these elements of well-being. We review evidence on the scale and scope of these climate change consequences for well-being and propose policy and research priorities that are oriented towards supporting well-being though a changing climate.
Observed poleward freshwater transport since 1970
Publisher: Springer Science and Business Media LLC
Date: 23-02-2022
DOI: 10.1038/S41586-021-04370-W
Abstract: Warming-induced global water cycle changes pose a significant challenge to global ecosystems and human society. However, quantifying historical water cycle change is difficult owing to a dearth of direct observations, particularly over the ocean, where 77% and 85% of global precipitation and evaporation occur, respectively
Facial Expressions
Publisher: Springer International Publishing
Date: 09-10-2019
Where are our ancestors? Rethinking Trobriand cosmology
Publisher: University of Chicago Press
Date: 09-2020
DOI: 10.1086/709521
The fear gasping face as a threat display in a Melanesian society
Publisher: Proceedings of the National Academy of Sciences
Date: 17-10-2016
Abstract: Humans interpret others’ facial behavior, such as frowns and smiles, and guide their behavior accordingly, but whether such interpretations are pancultural or culturally specific is unknown. In a society with a great degree of cultural and visual isolation from the West—Trobrianders of Papua New Guinea—adolescents interpreted a gasping face (seen by Western s les as conveying fear and submission) as conveying anger and threat. This finding is important not only in supporting behavioral ecology and the ethological approach to facial behavior, as well as challenging psychology’s approach of allegedly pancultural “basic emotions,” but also in applications such as emotional intelligence tests and border security.
Adiabatic and diabatic signatures of ocean temperature variability
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-2085
Abstract: & & Anthropogenically induced radiative imbalances in the climate system lead to a slow accumulation of heat in the ocean. This warming is often obscured by natural modes of climate variability such as the El Nino-Southern Oscillation (ENSO), which drive substantial ocean temperature changes as a function of depth and latitude. The use of watermass coordinates has been proposed to help isolate forced signals and filter out fast adiabatic processes associated with modes of variability. However, how much natural modes of variability project into these different coordinate systems has not been quantified. Here we apply a rigorous framework to quantify ocean temperature variability using both a quasi-Lagrangian watermass-based temperature coordinate and Eulerian depth and latitude coordinates in a free-running climate model under pre-industrial conditions. The temperature-based coordinate effectively filters out the adiabatic component of ENSO-dominated interannual variability, while a substantial diabatic signal remains. At slower (decadal to centennial) frequencies, variability in the temperature- and depth-based coordinates is comparable. Spectral analysis of temperature tendencies reveals the dominance of advective processes in latitude- and depth-coordinates while the variability in temperature-coordinates is related closely to the surface forcing. Diabatic mixing processes play an important role at slower frequencies where quasi steady-state balances emerge between forcing and mixing in temperature, advection and mixing in depth and forcing and advection in latitude. Our work suggests that watermass based analyses accurately filter out adiabitic variability and highlight diabatic effects, but also that natural variability has a strong diabatic component and can not be ignored in the analysis of long term trends.& &
Adiabatic and Diabatic Signatures of Ocean Temperature Variability
Publisher: American Meteorological Society
Date: 03-2022
Abstract: Anthropogenically induced radiative imbalances in the climate system lead to a slow accumulation of heat in the ocean. This warming is often obscured by natural modes of climate variability such as El Niño–Southern Oscillation (ENSO), which drive substantial ocean temperature changes as a function of depth and latitude. The use of watermass coordinates has been proposed to help isolate forced signals and filter out fast adiabatic processes associated with modes of variability. However, how much natural modes of variability project into these different coordinate systems has not been quantified. Here we apply a rigorous framework to quantify ocean temperature variability using both a quasi-Lagrangian, watermass-based temperature coordinate and Eulerian depth and latitude coordinates in a free-running climate model under preindustrial conditions. The temperature-based coordinate removes the adiabatic component of ENSO-dominated interannual variability by definition, but a substantial diabatic signal remains. At slower (decadal to centennial) frequencies, variability in the temperature- and depth-based coordinates is comparable. Spectral analysis of temperature tendencies reveals the dominance of advective processes in latitude and depth coordinates while the variability in temperature coordinates is related closely to the surface forcing. Diabatic mixing processes play an important role at slower frequencies where quasi-steady-state balances emerge between forcing and mixing in temperature, advection and mixing in depth, and forcing and advection in latitude. While watermass-based analyses highlight diabatic effects by removing adiabatic variability, our work shows that natural variability has a strong diabatic component and cannot be ignored in the analysis of long-term trends. Quantifying the ocean warming associated with anthropogenically induced radiative imbalances in the climate system can be challenging due to the superposition with modes of internal climate variability such as El Niño. One method proposed to address this issue is the analysis of temperature changes in fluid-following (or “watermass”) coordinates that filter out fast adiabatic processes associated with these modes of variability. In this study we compare a watermass-based analysis with more traditional analyses of temperature changes at fixed depth and latitude to show that even natural modes of climate variability exhibit a substantial signal in watermass coordinates, particularly at decadal and slower frequencies. This natural variability must be taken into account when analyzing long-term temperature trends in the ocean.
New estimates of observed poleward freshwater transport since 1970
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-1377
Abstract: & & Global water cycle changes induced by anthropogenic climate change pose a growing threat to existing ecosystems and human infrastructure. However, scarce direct observations of precipitation and evaporation means historical water cycle changes remain uncertain. In this work, we apply a novel watermass-based diagnostic framework to the latest observations of ocean salinity to quantify poleward freshwater transport in the earth system since 1970. This observational estimate is not replicated in any model in the current generation of CMIP6 climate models - likely due to the inaccurate representation of surface freshwater flux intensification in such models. These results provide a first-of-its-kind baseline of observed warm-to-cold freshwater transport since 1970, and also underscore the need to further explore surface freshwater fluxes in existing climate models.& &
What is the heat uptake potential of Antarctic Bottom Water?
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-3825
Abstract: & & Antarctic Bottom Water (AABW) is a cold dense water mass which sinks around Antarctica keeping the abyssal ocean relatively cool. Recent observations have suggested a component of recent deep ocean warming is linked to AABW. Here we explore how much changes in AABW could affect changes in vertical ocean heat transport in a warming climate. If the AABW circulation were to be completely extinguished, for ex le due to increases in upper ocean thermal stratification, AABW would cease to cool the deep ocean and hence lead to an effective warming of the abyss. Therefore, we propose that long term mean vertical heat transport of the AABW circulation is an effective upper bound on the change in heat transport that can be affected by changes in AABW. We call this upper bound the & #8216 heat uptake potential& #8217 . We analyse AABW circulations in an ensemble of numerical climate models. We find that the AABW circulation contributes between 0.05Wm& sup& -2& /sup& and 0.15Wm& sup& -2& /sup& to the global vertical heat balance in the model& #8217 s pre-industrial states. Indeed, under abrupt CO& sub& & /sub& forcing changes, AABW heat transport systematically reduces (in some cases completely), with the largest reductions occurring in models with the largest pre-industrial mean heat transports. The AABW circulation vertical heat transport is found to be highly correlated with the minimum of the Meridional Overturning Circulation at 50& sup& o& /sup& S in the models, suggesting there may be observable constraints on the heat uptake potential of AABW.& &
Fifty Year Trends in Global Ocean Heat Content Traced to Surface Heat Fluxes in the Sub‐Polar Ocean
Publisher: American Geophysical Union (AGU)
Date: 24-04-2021
DOI: 10.1029/2020GL091439
Abstract: The ocean has absorbed approximately 90% of the accumulated heat in the climate system since 1970. As global warming accelerates, understanding ocean heat content changes and tracing these to surface heat input is increasingly important. We introduce a novel framework by organizing the ocean into temperature‐percentiles from warmest to coldest, allowing us to trace ocean temperature changes to changes in surface fluxes and mixing. Applying this framework to observations and historical CMIP6 simulations, we find that 50 ± 6% of surface heat uptake between 1970 and 2014 is confined to isotherms in the coldest 90% of the ocean volume. These isotherms outcrop over only 23% of the ocean's surface area in the sub‐polar regions, implying a disproportionately large heat input per unit area. Additionally, a cooling bias in the CMIP6 models is traced to inaccurate sea surface temperatures and surface heat fluxes into the warmest 5%–20% of the ocean volume.
Watermass co-ordinates isolate the historical climate change signal
Publisher: Wiley
Date: 18-05-2022
Climate change and migration from atolls? No evidence yet
Publisher: Elsevier BV
Date: 02-2023
The Tuma Underworld of Love. Erotic and Other Narrative Songs of the Trobriand Islanders and their Spirits of the Dead - By Gunter Senft
Publisher: Wiley
Date: 11-2017
DOI: 10.1002/OCEA.5172
Water-Mass Coordinates Isolate the Historical Ocean Warming Signal
Publisher: American Meteorological Society
Date: 05-2023
Abstract: Persistent warming and water cycle change due to anthropogenic climate change modifies the temperature and salinity distribution of the ocean over time. This “forced” signal of temperature and salinity change is often masked by the background internal variability of the climate system. Analyzing temperature and salinity change in water-mass-based coordinate systems has been proposed as an alternative to traditional Eulerian (e.g., fixed-depth, zonally averaged) coordinate systems. The impact of internal variability is thought to be reduced in water-mass coordinates, enabling a cleaner separation of the forced signal from background variability—or a higher “signal-to-noise” ratio. Building on previous analyses comparing Eulerian and water-mass-based one-dimensional coordinates, here we recast two-dimensional coordinate systems—temperature–salinity ( T – S ), latitude–longitude, and latitude–depth—onto a directly comparable equal-volume framework. We compare the internal variability, or “noise” in temperature and salinity between these remapped two-dimensional coordinate systems in a 500-yr preindustrial control run from a CMIP6 climate model. We find that the median internal variability is lowest (and roughly equivalent) in T – S and latitude–depth space, compared with latitude–longitude coordinates. A large proportion of variability in T – S and latitude–depth space can be attributed to processes that operate over a time scale greater than 10 years. Overall, the signal-to-noise ratio in T – S coordinates is roughly comparable to latitude–depth coordinates, but is greater in regions of high historical temperature change. Conversely, latitude–depth coordinates have greater signal-to-noise ratio in regions of historical salinity change. Thus, we conclude that the climatic temperature change signal can be more robustly identified in water-mass coordinates. Changes in ocean temperature and salinity are driven both by human-induced climate change and by modes of natural variability in the climate system, such as El Niño–Southern Oscillation. It can be difficult to isolate the human-induced “signal” of climate change from the natural fluctuations or “noise” in the climate system. Water-mass-based methods, which “follow” a parcel of water around the ocean, have been thought to improve on “Eulerian” (i.e., analyses performed at fixed latitude, longitude, and depth) frames of reference as they are less impacted by the noise. However, it is difficult to cleanly compare between water-mass-based methods and Eulerian methods. Here, we aim to quantify the extent to which water-mass-based frameworks improve on Eulerian frameworks in isolating the climate signal from the noise. We recast water-mass and Eulerian methods onto an equivalent grid, enabling a clean comparison between them, and find that doing so increases the signal-to-noise ratio in water-mass-based coordinates in regions of ocean warming. These results emphasize the utility of water-mass-based methods in analyzing long-term climatic temperature change in the ocean.
Reading emotions from faces in two indigenous societies.
Publisher: American Psychological Association (APA)
Date: 07-2016
DOI: 10.1037/XGE0000172
Abstract: That all humans recognize certain specific emotions from their facial expression-the Universality Thesis-is a pillar of research, theory, and application in the psychology of emotion. Its most rigorous test occurs in indigenous societies with limited contact with external cultural influences, but such tests are scarce. Here we report 2 such tests. Study 1 was of children and adolescents (N = 68 aged 6-16 years) of the Trobriand Islands (Papua New Guinea, South Pacific) with a Western control group from Spain (N = 113, of similar ages). Study 2 was of children and adolescents (N = 36 same age range) of Matemo Island (Mozambique, Africa). In both studies, participants were shown an array of prototypical facial expressions and asked to point to the person feeling a specific emotion: happiness, fear, anger, disgust, or sadness. The Spanish control group matched faces to emotions as predicted by the Universality Thesis: matching was seen on 83% to 100% of trials. For the indigenous societies, in both studies, the Universality Thesis was moderately supported for happiness: smiles were matched to happiness on 58% and 56% of trials, respectively. For other emotions, however, results were even more modest: 7% to 46% in the Trobriand Islands and 22% to 53% in Matemo Island. These results were robust across age, gender, static versus dynamic display of the facial expressions, and between- versus within-subjects design. (PsycINFO Database Record
Vertical Eddy Fluxes in the Southern Ocean
Publisher: American Meteorological Society
Date: 05-2013
Abstract: The overturning circulation of the Southern Ocean has been investigated using eddying coupled ocean–sea ice models. The circulation is diagnosed in both density–latitude coordinates and in depth–density coordinates. Depth–density coordinates follow streamlines where the Antarctic Circumpolar Current is equivalent barotropic, capture the descent of Antarctic Bottom Water, follow density outcrops at the surface, and can be interpreted energetically. In density–latitude coordinates, wind-driven northward transport of light water and southward transport of dense water are compensated by standing meanders and to a lesser degree by transient eddies, consistent with previous results. In depth–density coordinates, however, wind-driven upwelling of dense water and downwelling of light water are compensated more strongly by transient eddy fluxes than fluxes because of standing meanders. Model realizations are discussed where the wind pattern of the southern annular mode is lified. In density–latitude coordinates, meridional fluxes because of transient eddies can increase to counter changes in Ekman transport and decrease in response to changes in the standing meanders. In depth–density coordinates, vertical fluxes because of transient eddies directly counter changes in Ekman pumping.
Rejoinder to Kret and Straffon
Publisher: Elsevier BV
Date: 12-2018
Reply to “Comments on ‘Diathermal Heat Transport in a Global Ocean Model’”
Publisher: American Meteorological Society
Date: 08-2019
Abstract: Hochet and Tailleux (2019), in a comment on Holmes et al. (2019), argue that under the incompressible Boussinesq approximation the “sum of the volume fluxes through any kind of control volume must integrate to zero at all times.” They hence argue that the expression in Holmes et al. (2019) for the change in the volume of seawater warmer than a given temperature is inaccurate. Here we clarify what is meant by the term “volume flux” as used in Holmes et al. (2019) and also more generally in the water-mass transformation literature. Specifically, a volume flux across a surface can occur either due to fluid moving through a fixed surface, or due to the surface moving through the fluid. Interpreted in this way, we show using several ex les that the statement from Hochet and Tailleux (2019) quoted above does not apply to the control volume considered in Holmes et al. (2019). Hochet and Tailleux (2019) then derive a series of expressions for the water-mass transformation or volume flux across an isotherm in the general, compressible case. In the incompressible Boussinesq limit these expressions reduce to a form (similar to that provided in Holmes et al. 2019) that involves the temperature derivative of the diabatic heat fluxes. Due to this derivative, can be difficult to robustly estimate from ocean model output. This emphasizes one of the advantages of the approach of Holmes et al. (2019), namely, does not appear in the internal heat content budget and is not needed to describe the flow of internal heat content into and around the ocean.
Believing the unbelieved Reincarnation, cultural authority, and politics in the Trobriand Islands
Publisher: University of Chicago Press
Date: 09-2020
DOI: 10.1086/709553
Super Residual Circulation: a new perspective on ocean vertical heat transport
Publisher: American Meteorological Society
Date: 21-05-2021
Abstract: Ocean circulation and mixing regulate Earth’s climate by moving heat vertically within the ocean. We present a new formalism to diagnose the role of ocean circulation and diabatic processes in setting vertical heat transport in ocean models. In this formalism we use temperature tendencies, rather than explicit vertical velocities to diagnose circulation. Using quasi-steady state simulations from the Australian Community Climate and Earth-System Simulator Ocean Model (ACCESS-OM2), we diagnose a diathermal overturning circulation in temperature-depth space. Furthermore, projection of tendencies due to diabatic processes onto this coordinate permits us to represent these as apparent overturning circulations. Our framework permits us to extend the concept of Super-Residual Transport (SRT), which combines mean and eddy advection terms with subgridscale isopycnal mixing due to mesoscale eddies, but excludes small-scale three dimensional turbulent mixing effect, to construct a new overturning circulation – the ‘Super Residual Circulation’ (SRC). We find that in the coarse resolution version of ACCESS-OM2 (nominally 1° horizontal resolution) the SRC is dominated by an ~11 Sv circulation which transports heat upward. The SRC’s upward heat transport is ~2 times larger in a finer horizontal resolution (0.1°) version of ACCESS, suggesting a differing balance of super-residual and parameterized small-scale processes may emerge as eddies are resolved. Our analysis adds new insight into super-residual processes, as the SRC elucidates the pathways in temperature and depth space along which watermass transformation occurs.
Long-term global ocean heat content change driven by sub-polar surface heat fluxes
Publisher: Wiley
Date: 09-11-2020
Contingent communality and community-based adaptation to climate change: Insights from a Pacific rural atoll
Publisher: Elsevier BV
Date: 10-2021
Reducing personal climate anxiety is key to adaptation
Publisher: Springer Science and Business Media LLC
Date: 29-06-2023
Anthropogenic aerosols offsetting ocean warming less efficiently since the 1980s
Publisher: Authorea, Inc.
Date: 20-07-2023
DOI: 10.22541/ESSOAR.168987142.28631718/V1
Abstract: Greenhouse gases and aerosols play a major role in controlling global climate change. Greenhouse gases drive a radiative imbalance which warms the ocean, while aerosols cool the ocean. Since 1980, the effective radiation felt by the planet due to anthropogenic aerosols has levelled off, global ocean cooling due to aerosols has decelerated, and greenhouse gas-driven ocean warming has accelerated. We explore the deceleration of aerosol-driven ocean cooling by quantifying a time- and spatially-varying ocean heat uptake efficiency, defined as the change in the rate of global ocean heat storage per degree of cooling surface temperature. In aerosol-only simulations, ocean heat uptake efficiency has decreased by 69% since the 1900s. The tropics and sub-tropics have driven this decrease, while the coldest fraction of the ocean continues to sustain cooling and high ocean heat uptake efficiency. Our results identify a growing trend towards less efficient ocean cooling due to aerosols.
A Multidisciplinary Approach to Research in Small-Scale Societies: Studying Emotions and Facial Expressions in the Field
Publisher: Frontiers Media SA
Date: 18-07-2016
Trobriand Tales, Kwanebuyee Kilivila
Publisher: Smithsonian Institution
Date: 26-02-2021
Abstract: This volume comprises an edited compilation of traditional oral narratives from the Trobriand Islands of Papua New Guinea obtained by Jerry W. Leach from 1970 to 1973, which are held in the Smithsonian Institution’s National Anthropological Archives. The narratives encompass key aspects of Trobriand cultural heritage as well as insights into the Kilivila language, regional cosmologies, and past and present social practices. The narratives constitute an elaborate but fragile system of knowledge that is threatened by rapid social change. The book is the culmination of a research project begun in 2011 through the auspices of the Recovering Voices Program at the National Museum of Natural History. Traveling to the Trobriand Islands with copies of the Leach narratives, the editor worked with communities to select the most culturally important and prevalent narratives, 79 of which are presented here. Trobriand communities proposed that those narratives be printed in Kilivila and in English to help preserve traditional knowledge for future generations. Each narrative is categorized in local terms, preceded by details regarding the storytellers and a summary, as well as links to other stories when narratives are related, and many are followed by a list of key words and expressions that are defined in a section on vocabulary. Further explanations and illustrations help clarify and complete the stories, providing ex les of traditional objects and techniques as well as their uses.
Internal salt content: a useful framework for understanding the oceanic branch of the water cycle
Publisher: American Meteorological Society
Date: 13-04-2021
Abstract: The global water cycle is dominated by an atmospheric branch which transfers fresh water away from subtropical regions and an oceanic branch which returns that fresh water from subpolar and tropical regions. Salt content is commonly used to understand the oceanic branch because surface freshwater fluxes leave an imprint on ocean salinity. However, freshwater fluxes do not actually change the amount of salt in the ocean and – in the mean – no salt is transported meridionally by ocean circulation. To study the processes which determine ocean salinity we introduce a new variable: “internal salt” and its counterpart “internal fresh water”. Precise budgets for internal salt in salinity coordinates relate meridional and diahaline transport to surface freshwater forcing, ocean circulation and mixing, and reveal the pathway of fresh water in the ocean. We apply this framework to a 1° global ocean model. We find that in order for fresh water to be exported from the ocean’s tropical and subpolar regions to the subtropics, salt must be mixed across the salinity surfaces that bound those regions. In the tropics, this mixing is achieved by parameterized vertical mixing, along-isopycnal mixing, and numerical mixing associated with truncation errors in the model’s advection scheme, while along-isopycnal mixing dominates at high latitudes. We analyze the internal freshwater budgets of the Indo-Pacific and Atlantic Ocean basins and identify the transport pathways between them which redistribute fresh water added through precipitation, balancing asymmetries in freshwater forcing between the basins.
Atlantic Ocean Heat Transport Enabled by Indo‐Pacific Heat Uptake and Mixing
Publisher: American Geophysical Union (AGU)
Date: 11-12-2019
DOI: 10.1029/2019GL085160
Nature-based solutions for atoll habitability
Publisher: The Royal Society
Date: 16-05-2022
Abstract: Atoll societies have adapted their environments and social systems for thousands of years, but the rapid pace of climate change may bring conditions that exceed their adaptive capacities. There is growing interest in the use of ‘nature-based solutions' to facilitate the continuation of dignified and meaningful lives on atolls through a changing climate. However, there remains insufficient evidence to conclude that these can make a significant contribution to adaptation on atolls, let alone to develop standards and guidelines for their implementation. A sustained programme of research to clarify the potential of nature-based solutions to support the habitability of atolls is therefore vital. In this paper, we provide a prospectus to guide this research programme: we explain the challenge climate change poses to atoll societies, discuss past and potential future applications of nature-based solutions and outline an agenda for transdisciplinary research to advance knowledge of the efficacy and feasibility of nature-based solutions to sustain the habitability of atolls. This article is part of the theme issue ‘Nurturing resilient marine ecosystems’.
Diathermal Heat Transport in a Global Ocean Model
Publisher: American Meteorological Society
Date: 2019
Abstract: The rate at which the ocean moves heat from the tropics toward the poles, and from the surface into the interior, depends on diabatic surface forcing and diffusive mixing. These diabatic processes can be isolated by analyzing heat transport in a temperature coordinate (the diathermal heat transport). This framework is applied to a global ocean sea ice model at two horizontal resolutions (1/4° and 1/10°) to evaluate the partioning of the diathermal heat transport between different mixing processes and their spatial and seasonal structure. The diathermal heat transport peaks around 22°C at 1.6 PW, similar to the peak meridional heat transport. Diffusive mixing transfers this heat from waters above 22°C, where surface forcing warms the tropical ocean, to temperatures below 22°C where midlatitude waters are cooled. In the control 1/4° simulation, half of the parameterized vertical mixing is achieved by background diffusion, to which sensitivity is explored. The remainder is associated with parameterizations for surface boundary layer, shear instability, and tidal mixing. Nearly half of the seasonal cycle in the peak vertical mixing heat flux is associated with shear instability in the tropical Pacific cold tongue, highlighting this region’s global importance. The framework presented also allows for quantification of numerical mixing associated with the model’s advection scheme. Numerical mixing has a substantial seasonal cycle and increases to compensate for reduced explicit vertical mixing. Finally, applied to Argo observations the diathermal framework reveals a heat content seasonal cycle consistent with the simulations. These results highlight the utility of the diathermal framework for understanding the role of diabatic processes in ocean circulation and climate.
The Geography of Numerical Mixing in a Suite of Global Ocean Models
Publisher: American Geophysical Union (AGU)
Date: 07-2021
DOI: 10.1029/2020MS002333
Abstract: Numerical mixing, defined here as the physically spurious tracer diffusion due to the numerical discretization of advection, is known to contribute to biases in ocean models. However, quantifying numerical mixing is nontrivial, with most studies utilizing targeted experiments in idealized settings. Here, we present a water mass transformation‐based method for quantifying numerical mixing that can be applied to any conserved variable in general circulation models. Furthermore, the method can be applied within in idual fluid columns to provide spatial information. We apply the method to a suite of global ocean model simulations with differing grid spacings and subgrid‐scale parameterizations. In all configurations numerical mixing drives diathermal heat transport of comparable magnitude to that associated with explicit parameterizations. Numerical mixing is prominent in the tropical thermocline, where it is sensitive to the vertical diffusivity and resolution. At colder temperatures numerical mixing is sensitive to the presence of explicit neutral diffusion, suggesting that it may act as a proxy for neutral diffusion when it is explicitly absent. Comparison of otherwise equivalent 1/4° and 1/10° configurations with grid‐scale dependent horizontal viscosity shows only a modest enhancement in numerical mixing at 1/4°. However, if the lateral viscosity is maintained while resolution is increased then numerical mixing is reduced by almost 35 % . This result suggests that the common practice of reducing viscosity in order to maximize permitted variability must be considered carefully. Our results provide a detailed view of numerical mixing in ocean models and pave the way for improvements in parameter choices and numerical methods.
The Kula of the Gospels: Christianity, Magic, and Exchange in the Trobriand Islands
Publisher: Project MUSE
Date: 2022
DOI: 10.1353/CP.2022.0059
How Malinowski sailed the Midnight Sun: the academic conference as ethnographic performance
Publisher: Wiley
Date: 17-04-2021
Recognizing spontaneous facial expressions of emotion in a small-scale society of Papua New Guinea.
Publisher: American Psychological Association (APA)
Date: 03-2017
DOI: 10.1037/EMO0000236
Abstract: We report 2 studies on how residents of Papua New Guinea interpret facial expressions produced spontaneously by other residents of Papua New Guinea. Members of a small-scale indigenous society, Trobrianders (Milne Bay Province N = 32, 14 to 17 years) were shown 5 facial expressions spontaneously produced by members of another small-scale indigenous society, Fore (Eastern Highlands Province) that Ekman had photographed, labeled, and published in The Face of Man (1980), each as an expression of a basic emotion: happiness, sadness, anger, surprise, and disgust. Trobrianders were asked to use any word they wanted to describe how each person shown felt and to provide valence and arousal ratings. Other Trobrianders (N = 24, 12 to 14 years) were shown the same photographs but asked to choose their response from a short list. In both studies, agreement with Ekman's predicted labels was low: 0% to 16% and 13% to 38% of observers, respectively. (PsycINFO Database Record
An optimal transformation method for inferring ocean tracer sources and sinks
Publisher: Copernicus GmbH
Date: 10-07-2023
DOI: 10.5194/EGUSPHERE-2023-1220
Abstract: Abstract. The geography of changes in the fluxes of heat, carbon, fresh water and other tracers at the sea surface are highly uncertain and are critical to our understanding of climate change and its impacts. We present a state estimation framework wherein the relative roles of ocean circulation, boundary fluxes and mixing, which describe the evolving state of water masses, can be balanced. In this framework, we define a discrete set of ocean water masses distinguished by their geographical and thermodynamic/chemical properties for specific time periods. Ocean circulation then moves these water masses in geographic space. In phase space, geographically adjacent water masses are able to mix together, representing a convergence, and air-sea property fluxes move the water masses over time. We define an optimisation problem whose solution is constrained by the physically permissible bounds of changes in ocean circulation, air-sea fluxes and mixing. As a proof of concept implementation, we use data from a historical numerical climate model simulation with a closed heat and salinity budget. An inverse model solution is found for the evolution of temperature and salinity consistent with `true' air-sea heat and fresh water fluxes which are introduced as model priors. When a constant bias is introduced to the prior fluxes, the inverse model finds a solution closer to the true fluxes. This framework, which we call the Optimal Transformation Method, represents a modular, relatively computationally cost effective, open source and transparent state estimation tool that complements existing approaches.
“Winga Is Trying to Get in”: Local Observations of Climate Change in the Tiwi Islands
Publisher: American Geophysical Union (AGU)
Date: 03-2023
DOI: 10.1029/2022EF002808
Abstract: There is a growing body of research documenting Indigenous Peoples and Local Communities' observations of changes in climate. The accuracy, efficacy, and transferability of this research depends on its motives and methods. In this paper, we report on research to produce a working knowledge of changes in climate and its impacts on local biophysical systems in the Tiwi Islands in Northern Australia. Interviews with 52 Tiwi people were combined with erse forms of aerial data to produce a nuanced understanding of climate change in these remote islands. These data show changes in climate‐sensitive biophysical systems that would otherwise remain undetected by instruments conventionally used for monitoring climate change. These include changes in shorelines, which are causing concerns about damage to buildings that are important for Tiwi well‐being, and changes in the marine environment and wetlands, which are causing concerns about damage to natural heritage. We discuss the implications of these findings, arguing that systematic observations collected by networks of people “on Country” can provide excellent monitoring of climate change impacts, and that Indigenous people's interests in the effects of climate change overlap with those of non‐Indigenous people, as do their rights to support from the State for adaptation.
Repositioning the (Is)land: Climate Change Adaptation and the Atoll Assemblage
Publisher: Wiley
Date: 03-2022
DOI: 10.1111/ANTI.12814
Abstract: Sinking atolls are an enduring symbol of the power of climate change to destroy inhabited places. Climate impact science and the media share a panoptic gaze on atoll islands seeing them as being small, inert and passive in the face of rising seas. The focus in these accounts is on the power of water as the agent of destruction, while the agency of the assemblage of human and non‐human actors that is the (is)land itself is ignored. Thus, atolls are said to be vulnerable, and the prevailing ideas of adaptation are either international relocation to avoid the sea or seawalls to contain it. Based on qualitative field research in Pacific atolls, this paper examines the connections between island peoples and their terrestrial environments, and the work that they are doing in response to the impacts of climate change. It shows how land is conceived symbolically, socio‐culturally and legally, and considers its role in sustaining livelihoods and anchoring identities through a changing climate.
The geography of numerical mixing in a suite of global ocean models
Publisher: Copernicus GmbH
Date: 04-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-9319
Abstract: & & Numerical mixing, the physically spurious diffusion of tracers due to the numerical discretization of advection, is known to contribute to biases in ocean circulation models. However, quantifying numerical mixing is non-trivial, with most studies utilizing specifically targeted experiments in idealized settings. Here, we present a precise method based on water-mass transformation for quantifying numerical mixing, including its spatial structure, that can be applied to any conserved variable in global general circulation ocean models. The method is applied to a suite of global MOM5 ocean-sea ice model simulations with differing grid spacings and sub-grid scale parameterizations. In all configurations numerical mixing drives across-isotherm heat transport of comparable magnitude to that associated with explicitly-parameterized mixing. Numerical mixing is prominent at warm temperatures in the tropical thermocline, where it is sensitive to the vertical diffusivity and resolution. At colder temperatures, numerical mixing is sensitive to the presence of explicit neutral diffusion, suggesting that much of the numerical mixing in these regions acts as a proxy for neutral diffusion when it is explicitly absent. Comparison of equivalent (with respect to vertical resolution and explicit mixing parameters) 1/4-degree and 1/10-degree horizontal resolution configurations shows only a modest enhancement in numerical mixing at the eddy-permitting 1/4-degree resolution. Our results provide a detailed view of numerical mixing in ocean models and pave the way for future improvements in numerical methods.& &
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Laboratoire Des Ecoulements Géophysiques Et Industriels
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Imperial College London
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University Of Southampton
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University Of Cambridge
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National Museum Of Natural History
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American Museum Of Natural History
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Related Funding Activities
Australian Centre For Excellence In Antarctic Science
Start Date: 2021
End Date: 2024
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE200100040
Start Date: 04-2020
End Date: 07-2021
Amount: $580,000.00
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View Funded ActivityDiscovery Projects - Grant ID: DP190101173
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View Funded ActivitySpecial Research Initiatives - Grant ID: SR200100008
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