School of Geography, Earth and Atmospheric Sciences - Research Publications
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ItemOn the destructive tendencies of cratons(GEOLOGICAL SOC AMER, INC, 2021-02-01)We propose that subducting slabs may cause lithospheric removal by directing mantle flow along the craton margin. This process could carve and shape the cratons, leading to conditions that impact the overall (in)stability of the lithosphere. We use three-dimensional geodynamic models to investigate how subduction-driven directed flow interacts with cratonic lithosphere of differing shape, concluding that the margin shape controls both channelization of flow around the craton as well as the potential for destruction. While the simulations show that all craton shapes aid in channelization, the cratons with straight vertical margins are the most resistant to deformation, and the cratons with gradually thickening margins are less resistant to deformation. The dependence on shape could contribute to the progressive removal of cratonic lithosphere along its margin in a runaway process until a more stable vertical margin shape evolves.
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ItemInclusive mainstream services for people with intellectual disabilities: A relational approach(ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2024-01-01)
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ItemContinuing existence: viability and indigenous youth action in Himachal Pradesh, India(Informa UK Limited, 2024-01-01)
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ItemScratching the surface: Subtractive rock markings from the Cockburn Ranges, eastern Kimberley, Western Australia(TAYLOR & FRANCIS LTD, 2023-09-02)
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ItemWet deposition in shallow convection over the Southern Ocean(Springer Science and Business Media LLC, 2024-12-01)Abstract Southern Ocean (SO) air is amongst the most pristine on Earth, particularly during winter. Historically, there has been a focus on biogenic sources as an explanation for the seasonal cycle in cloud condensation nuclei concentrations (NCCN). NCCN is also sensitive to the strength of sink terms, although the magnitude of this term varies considerably. Wet deposition, a process encompassing coalescence scavenging (drizzle formation), is one such process that may be especially relevant over the SO. Using a boundary layer cloud climatology, NCCN and precipitation observations from Kennaook/Cape Grim Observatory (CGO), we find a statistically significant difference in NCCN between when the upwind meteorology is dominated by open mesoscale cellular convection (MCC) and closed MCC. When open MCC is dominant, a lower median NCCN (69 cm−3) is found compared to when closed MCC (89 cm−3) is dominant. Open MCC is found to precipitate more heavily (1.72 mm day−1) and more frequently (16.7% of the time) than closed MCC (0.29 mm day−1, 4.5%). These relationships are observed to hold across the seasonal cycle with maximum NCCN and minimum precipitation observed during Austral summer (DJF). Furthermore, the observed MCC morphology strongly depends on meteorological conditions. The relationship between NCCN and precipitation can be further examined across a diurnal cycle during the summer season. Although there was again a negative relationship between precipitation and NCCN, the precipitation cycle was out of phase with the NCCN cycle, leading it by ~3 hours, suggesting other factors, specifically the meteorology play a primary role in influencing precipitation.
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ItemSurface Wave Mixing Modifies Projections of 21st Century Ocean Heat Uptake(MDPI, 2023-03)Climate models do not explicitly account for the smaller scale processes of ocean surface waves. However, many large-scale phenomena are essentially coupled with the waves. In particular, waves enhance mixing in the upper ocean and thereby accelerate the ocean response to atmospheric changes. Here, we introduced a representation of wave-induced turbulent mixing into the one-way coupled ACCESS-OM2-025 ocean model to study its effect on ocean heat content throughout the 21st century under the RCP4.5 scenario. We made two projections on ocean heat uptake for the end of the century: one which accounts for wave-induced mixing (the ‘modified’ projection) and the other which does not (the ‘standard’ projection). Both projections showed upper ocean heat content to increase by more than 2.2 × 1022 J. This projected ocean heat uptake was reduced by about 3% in the modified projection. Whilst the inclusion of wave-induced mixing reduces projected ocean heat uptake globally, some areas are expected to warm considerably faster, particularly the North Atlantic sub-tropics, the Tasman Sea, the Sea of Japan, and parts of the South Atlantic.
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ItemTropical vegetation productivity and atmospheric methane over the last 40,000 years from model simulations and stalagmites in Sulawesi, Indonesia(Cambridge University Press (CUP), 2024-03-26)Abstract Recent research has shown the potential of speleothem δ13C to record a range of environmental processes. Here, we report on 230Th-dated stalagmite δ13C records for southwest Sulawesi, Indonesia, over the last 40,000 yr to investigate the relationship between tropical vegetation productivity and atmospheric methane concentrations. We demonstrate that the Sulawesi stalagmite δ13C record is driven by changes in vegetation productivity and soil respiration and explore the link between soil respiration and tropical methane emissions using HadCM3 and the Sheffield Dynamic Global Vegetation Model. The model indicates that changes in soil respiration are primarily driven by changes in temperature and CO2, in line with our interpretation of stalagmite δ13C. In turn, modelled methane emissions are driven by soil respiration, providing a mechanism that links methane to stalagmite δ13C. This relationship is particularly strong during the last glaciation, indicating a key role for the tropics in controlling atmospheric methane when emissions from high-latitude boreal wetlands were suppressed. With further investigation, the link between δ13C in stalagmites and tropical methane could provide a low-latitude proxy complementary to polar ice core records to improve our understanding of the glacial–interglacial methane budget.
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ItemPartial planned relocation and livelihoods: Learnings from Narikoso, Fiji(WILEY, 2024-01-01)Pacific Island Countries (PICs) are vulnerable to climate change impacts, including sea level rise, extreme weather events and other environmental changes. Planned relocation can be an adaptive response to climatic threats. In Fiji, six communities have already relocated. While there is growing interest in planned relocation, there are few empirical case studies from which to learn. Narikoso village, in the Kadavu Province of Fiji, undertook partial relocation in 2020. Drawing on qualitative research (interviews, group discussions, observation), informed by Vanua methodology in 2022, this study examines the impacts of partial planned relocation on people's lives and livelihoods. Seven sustainable livelihood assets – or forms of ‘capital’ – are explored: natural, social, financial, human, physical and cultural, with the addition of spiritual. Our research found that planned relocation altered forms of capital that underpin sustainable livelihoods, leading to both benefits and problems. We argue that planned relocation must not only reduce exposure to climatic and environmental risk, but promote and preserve the integrity of local ecosystems, value continuity of culture and sustain and develop diverse assets that support sustainable livelihoods. This demands deep engagement with climate change‐affected communities to ensure that planned relocations sustain people's livelihoods, dignity and survival.
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ItemCharacterizing Precipitation and Improving Rainfall Estimates Over the Southern Ocean Using Ship-Borne Disdrometer and Dual-Polarimetric C-Band Radar(AMER GEOPHYSICAL UNION, 2024-03-28)Abstract Large satellite discrepancies and model biases in representing precipitation over the Southern Ocean (SO) are related directly to the region's limited surface observations of precipitation. To help address this knowledge gap, the study investigated the precipitation characteristics and rain rate retrievals over the remote SO using ship‐borne data of the Ocean Rainfall And Ice‐phase precipitation measurement Network disdrometer (OceanRAIN) and dual‐polarimetric C‐band radar (OceanPOL) aboard the Research Vessel (RV) Investigator in the Austral warm seasons of 2016–2018. Seven distinct synoptic types over the SO were analyzed based on their radar polarimetric signatures, surface precipitation phase, and rain microphysical properties. OceanRAIN observations revealed that the SO precipitation was dominated by drizzle and light rain, with small‐sized raindrops (diameter <1 mm) constituting up to 47% of total accumulation. Precipitation occurred most frequently over the warm sector of extratropical cyclones, while concentrations of large‐sized raindrops (diameter >3 mm) were prominent over synoptic types with colder and more convectively unstable environments. OceanPOL observations complement and extend the surface precipitation properties sampled by OceanRAIN, providing unique information to help characterize the variety of potential precipitation types and associated mechanisms under different synoptic conditions. Raindrop size distributions (DSD) measured with OceanRAIN over the SO were better characterized by analytical DSD forms with two‐shape parameters than single‐shape parameters currently implemented in satellite retrieval algorithms. This study also revised a rainfall retrieval algorithm for C‐band radars to reflect the large amount of small drops and provide improved radar rainfall estimates over the SO.
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ItemHousing affordability stress and mental health: The role of financial wellbeing(WILEY, 2024-01-01)Abstract Using data from wave 20 of the Household, Income and Labour Dynamics in Australia Survey, we provide a descriptive examination of the relationship between housing affordability stress (HAS) and a multi‐item measure of financial wellbeing across tenure types and test whether good financial wellbeing is protective of the negative mental health effects of HAS. We find that HAS is associated with lower financial wellbeing and that this is differentially distributed by tenure, with renters who experience HAS reporting, on average, lower financial wellbeing than owners. This suggests that HAS, which focuses on income to define housing stress, is different to financial wellbeing. Being in control of finances and feeling financially secure are important components of the way in which financial hardship impacts mental health. Renters may be more likely to experience these issues than owners; hence, they fare worse in terms of their mental health when in HAS than owners do.