Journal Articles

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3D evaluation of fine-scale normalised DSMs in urban settings
(2020-09) Breytenbach, Andre
Humankind often needs to accurately model, identify and spatially quantify aboveground phenomena on the Earth’s surface for informed decision-making. Height data derived from digital elevation models (DEMs) is often used to achieve this. This study conducted a deterministic assessment of three normalised digital surface models (nDSMs) of different spatial resolutions, namely 2m, 4m and 12m, derived from VHR digital stereo aerial photography, tri-stereo Pléiades imagery and Tandem-X InSAR data, respectively. Covering a predominantly built-up area within a city landscape, the nDSMs were vertically and volumetrically compared to assess their quality and fit-for-use. In each case a consistent systematic evaluation was accomplished against a lidar derived reference surface at matching spatial resolutions (co-registered) using a semi-automated GIS routine. The relative height and volumetric errors were statistically analysed and described, including those computed individually over nine urban land cover/land use (LCLU) classes and several selected large buildings. Higher vertical accuracies were reported across single storey structures and areas with no to little or short vegetation, as apposed to substantially lower accuracies obtained over multi-levelled buildings and tall (dense) woody vegetation. Here significant underestimations of volumes exacerbated by lower spatial resolutions were also observed across each nDSM. Conversely, notable volume overestimations were found over predominantly grass-covered areas in especially the finer-scaled nDSMs. VHR elevation data is recommended to model and quantify aboveground elements spatially in 3D (e.g. buildings, earthworks and woody vegetation) in urban landscapes, but a sensitivity test beforehand remains critical to ensure more reliable outcomes for users and stakeholders alike.
A greener, rapid and accurate microwave-assisted hydrogen peroxide digestion method for ICP-OES determination of heavy metals in pet food samples
(2024-07) Ncube, N; Tancu, Yolanda; Mketo, N
Microwave-assisted hydrogen peroxide digestion (MW-AHPD) method for determination of Cd, As, Pb, Sn, and Cr in South African pet food samples by inductively coupled plasma-optical emission spectroscopic (ICP-OES) is reported. Multivariate tools and wheat flour certified reference material (FAP80467) assessed limiting factors and reproducibility of the methods respectively. The resulted optimum conditions were: 200 ◦ and 5 mol/L for temperature, time, sample mass and H 2 O 2 C, 40 mins, 0.5 g, concentration, respectively. The method demonstrated excellent accuracy (96–98%), reproducibility (≤ 2.1%) and high detection limits (0.0675–0.3765 µg/g). Then, real pet food samples made from maize, rice, vegetables, fish, and wheat were digested and concentration levels of Cd, Pb, As, Cr and Sn ranged between 11.2 and 22.6, 6.4–11.9, 3.44–13.4, 0.44–2.98 and 0.18–0.98 µg/ g, respectively. The three metal ions were above the minimum tolerable limits (Cd: 10 µg/g, Pb:10 µg/g, As: 12.5 µg/g) for some of the fish and wheat.
A novel biogenic silicon-based anode material for lithium-ion batteries: A review
(2024-08) Seroka, Ntalane S; Luo, Hongze; Khotseng, L
Silicon possesses a 10-fold specific capacity compared to commonly used carbon-based anodes. The volume instability, among other impediments for practical use of silicon anodes, leads to the rapid decay of the capacity because of poor cyclability. Urgent mechanisms are required to improve lithium-ion storage during cycling and prevent volume variation in the silicon structure. Biogenic silicon derived from sugarcane bagasse can be used in nanoelectronic devices. Over the years, electrode materials have been an essential part of battery components. Moreover, electrode materials are favourable for highly portable nanoelectronics, hybrid as well as pure electric vehicles, etc. Furthermore, the biogenic silicon chosen for this study was based on natural abundance, environmental friendliness, and affordability. However, most silicon anodes are hindered by unstable volume expansion, variation in solid electrolyte interface films, and poor electrical conductivity. The focus is on silicon anodes, recent developments, and the potential of biogenic silicon from sugarcane waste, exploring its physicochemical properties to meet the requirements of a suitable anode material.
A review of metal pollution in a transformed, urban South African Estuary
(2024-12) Ndhlovu, A; Adams, JB; Nel, M; Newman, Brent K; Rishworth, GM; Human, LRD
Metal pollutants enter coastal water bodies from agricultural, industrial, and domestic wastewater activities amongst other sources. These pollutants are often transported through the food chain to higher trophic levels including organisms such as fish. Ultimately, they may pass to humans that consume contaminated seafoods. As such, it is imperative to understand how metals in estuarine systems are transported across trophic levels. Baseline data on metal concentrations are of crucial importance to evaluate changes over time and amongst areas to inform management and conservation strategies. In this assessment, we compile and discuss a database of metal concentrations recorded in various environmental media in the Swartkops River estuary, as a baseline against which future comparisons can be made. The Swartkops Estuary is subjected to considerable anthropogenic pressure that has led to a deterioration in water quality. We also provide a conceptual model to understand the flow of metals in the estuary. We furthermore identify lines of future research that will address gaps and uncertainties in the existing data and provide recommendations for remediation. Studies on metal concentrations in the water column of the estuary are limited. Studies on metals in sediment suggest that the estuary is not significantly metal contaminated. While studies revealed that plants do accumulate metals and fauna studies show differences in metal concentrations in the tissue of invertebrates and fish. It is difficult to conclude if these fauna are accumulating metals in their tissue compared to historically and if concentrations reflect uptake as a consequence of exposure to metal contaminated water, sediment and food.
Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone
(2023-07) Singh, Asmita; Fietz, S; Thomalla, Sandy J; Sanchez, N; Ardelan, MV; Moreau, S; Kauko, HM; Fransson, A; Chierici, M; Ryan-Keogh, Thomas J
The high nutrient–low chlorophyll condition of the Southern Ocean is generally thought to be caused by the low bioavailability of micronutrients, particularly iron, which plays an integral role in phytoplankton photosynthesis. Nevertheless, the Southern Ocean experiences seasonal blooms that generally initiate in austral spring, peak in summer, and extend into autumn. This seasonal increase in primary productivity is typically linked to the seasonal characteristics of nutrient and light supply. To better understand the potential limitations on productivity in the Antarctic sea-ice zone (SIZ), the photophysiological response of phytoplankton to iron addition (2.0 nM FeCl3) was investigated during autumn along the Antarctic coast off Dronning Maud Land. Five short-term (24 h) incubation experiments were conducted around Astrid Ridge (68 S) and along a 6 E transect, where an autumn bloom was identified in the region of the western SIZ. Surface iron concentrations ranged from 0.27 to 1.39 nM around Astrid Ridge, and 0.56 to 0.63 nM along the 6 E transect. Contrary to expectation, the photophysiological response of phytoplankton to iron addition, measured through the photosynthetic efficiency and the absorption cross-section for photosystem II, showed no significant responses. It is thus proposed that since the autumn phytoplankton in the SIZ exhibited a lack of an iron limitation at the time of sampling, the ambient iron concentrations may have been sufficient to fulfil the cellular requirements. This provides new insights into extended iron replete postbloom conditions in the typically assumed iron deficient high nutrient–low chlorophyll Southern Ocean.
Accessibility of TB diagnostic services at primary healthcare clinics in the eThekwini district, South Africa: A geospatial analysis
(2024-09) Dlangalala, T; Musekiwa, A; Mckelly, David H; Baloyi, E; Phosa Mashamba-Thompson, T
Improving geographic access can aid in managing tuberculosis (TB) by enabling early diagnosis and treatment initiation. Although geospatial techniques have been used to map the transmission patterns of drug-resistant TB in South Africa, fewer studies have investigated the accessibility of TB diagnostic services. This study evaluated the accessibility of TB diagnostic services and disease distribution in the eThekwini district of South Africa. Methods In this cross-sectional study, population data for 2021 were disaggregated into smaller analysis units and then re-aggregated through the dasymetric mapping technique. Data on notified TB patients, including Global Positioning System coordinates of clinics, were obtained from the District of Health Information System, exported to ArcGIS 10.8.2 and used to calculate distances to the nearest clinics and hospitals. Results 92% of the population (3 730 494 people) in eThekwini could access TB diagnostic services within 5 km. Patients travelled an average distance of 4.7 km (range: 0.1–26.9 km). TB diagnostic services were highly accessible in the Northern and Central regions and moderately accessible in the predominately rural Western and Southern regions. The smallest population of eThekwini resides in rural areas; however, 40.7% of its residents live >5 km from a diagnosing facility, with patients in the South having to travel up to 44.5 km. TB incidence was higher in the predominately rural West and South regions compared with the Central and North regions which are mainly comprised of urban and suburban areas. Our findings also showed that 98.4% of the clinics in eThekwini were located within 30 km of a hospital at an average distance of 9.6 km within the district. However, the distribution of these hospitals does not demonstrate equitable access as the majority are located within the Central region, and fewer are found in the other three regions of eThekwini. Conclusions Addressing the disparities in access to TB diagnostic services is required in the eThekwini district. Leveraging the existing mobile health clinics can assist with this, particularly, in rural areas with inadequate access. Additionally, active-case finding should be intensified in these regions since they had a higher TB burden per population. Prioritising interventions in these areas is crucial for reducing the impact of the disease on affected communities.
Accessibility, affordability, and equity in long-term spatial planning: Perspectives from a developing country
(2022-05) Van Heerden, Quintin; Karsten, Carike; Holloway, Jennifer P; Petzer, Engela; Burger, Paul AD; Mans, Gerbrand G
City planners attempt to create more equitable spaces by providing and improving access to benefits of living in cities, especially for previously disadvantaged urban communities. To this extent, evidence-based decision making is required to adequately plan for and improve accessibility to several types of facilities. Accessibility studies in literature focus mostly on one element, which is sufficient when presenting methodological advancements, but it is limiting when providing decision support to city planners. This paper argues that these measurements should be expanded and there is a need for a nuanced view on accessibility for improved urban planning practices. Such a view is presented by simultaneously considering various categories of supply (employment, housing, transportation, health, education, police), multiple modes of transport (walking, private vehicle, numerous transit modes), two cost thresholds (distance-based and monetary cost), level of access (percentage of facilities that can be reached), while distinguishing between the socio-economic profiles of regions in the city on the demand side. This improves the understanding of affordability and equity in the study of accessibility. Furthermore, this paper expands two categories (education and housing) to explain the influence of capacity on accessibility and equity. Lastly, it couples a land-use model to some of the accessibility measures to show the usefulness of using such a combination in long-term spatial planning and what the effects will be without government intervention, again contributing to the understanding of, and planning for, more inclusive and equitable cities.
Acid mine drainage from gold mining in South Africa: Remediation, reuse, and resource recovery
(2024-07) Baloyi, Siwela J; Ramdhani, Nishani; Mbhele, Khangweleni R; Simate, GS
This review critically examines the effects of AMD from the gold mines of South Africa and available options. We also critically analyse case studies, research gaps, and the challenges and opportunities presented by the AMD. Our assessment indicates the availability of potential technological advancements that might flip the paradigm in favour of less sludge being produced, lower operational costs, and more effective AMD treatment strategies. This has led to the development of long-term plans for AMD treatment technologies and the recovery of important minerals. There is currently a demand for integrated AMD technologies that take a holistic approach to long-term AMD treatment. Reusing water and recovering valuable resources like sulphuric acid, rare earth elements, and other metals have received a lot of attention. Continued study and implementation of such strategies will support sustainable gold mining, address the environmental damage caused by AMD, and optimize resource and revenue-generating potentials.
Acoustics in South African classrooms: Regulations versus reality
(2021-08) Van Reenen, Coralie A; Du Plessis, Chrisna
This research set out to broaden the pool of evidence regarding the acoustic conditions at schools in South Africa. A review of local and international literature, standards and design guidelines shows that the ideal classroom acoustic conditions of 35 dBA ambient and 0.7 s reverberation time are required to enable a suitable environment for teaching and learning. A review of local literature revealed a very small body of knowledge regarding actual acoustic conditions and monitoring of classroom acoustics and that these cases demonstrated ambient noise levels in classrooms (whether occupied or unoccupied) to be above the recommendations of the relevant South African National Standard (SANS 10103). The limited local research promted the need for this case study. The findings of a province-wide survey of urban schools showed that traffic noise is the main source of noise disturbance in schools. A case study of five schools showed that the average outdoor noise level at schools exposed to traffic throughout the day is 63.3 dBA and the average indoor noise level at these schools when classrooms are unoccupied is approximately 58 dBA, which is significantly higher than the requirement. The reverberation time in classrooms was between 0.6 and 1.75 s. It is concluded that the current acoustic conditions in South African urban schools is poor when evaluated against the South African National Standards. However, since this is based on only five case studies, a broader study is required to understand the general conditions and establish suitable mitigation measures.
Active and passive organic carbon fluxes during a bloom in the Southern Ocean (South Georgia)
(2024-12) Major, W; Giering, SL; Ainsworth, A; Belcher, A; Blackbird, S; Bridger, M; Briggs, N; Carvalho, F; Clément, L; Thomalla, Sandy J
The Controls Over Mesopelagic Interior Carbon Storage (COMICS) cruise DY086 took place aboard the RRS Discovery in the South Atlantic during November and December, 2017. Physical, chemical, biogeochemical and biological data were collected during three visits to ocean observatory station P3, off the coast of South Georgia, during an austral spring bloom. A diverse range of equipment including CTD-rosette, Acoustic Doppler Current Profiler (ADCP), net deployments, marine snow catchers (MSCs), Stand Alone Pump System (SAPS) and PELAGRA Sediment Traps were used to produce a comprehensive, high-quality dataset. The data can provide excellent insight into regional biological carbon pump (BCP) processes; it is recommended for use by observational scientists and modellers to enhance understanding of ecosystem interactions relating to mesopelagic carbon storage.
Adapting environmental management systems for African ports
(2022-03) Arabi, Sumaiya; Taljaard, Susan; Weerts, Steven P
Globally sustainable environmental practices in ports have been linked to socio-economic benefits. While African ports are increasingly acknowledging environmental issues and starting to address these in environmental policy, many are still struggling with effective implementation of sound environmental management practices. Multiple factors have been identified as potentially contributing to these challenges including institutional limitations, financial constraints, and limited human and technical capacity. In this paper, we propose an EMS framework for African ports, based on international best practice, but customised to specific continental challenges, and taking guidance from integrated coastal management (ICM) best practice recognising that coastal systems are the broader domain within which ports are spatially situated. The Plan-Do-Check-Act (PDCA) model provides the adaptive management structure for the proposed EMS framework. We consider this framework as a logical and structured method to initiate the implementation of EMS in African ports more effectively, compatible with international standards such as ISO 14001. Unpacking each of the key components and elements within the PDCA model, together with motivation for their inclusion, provides greater transparency to port managers who ultimately have to understand and implement EMS processes.
Addressing plastic pollution and waste flows: Insights from South Africa’s experience
(2024-06) Oelofse, Suzanna HH; Russo, Valentina; Stafford, William HL
The Pew Charitable Trust's 2020 report 'Breaking the Plastic Wave', indicates that existing technologies could support an 80% reduction in plastic leakage relative to business as usual by 2040. Therefore, South Africa became the first country to work with the Pew Charitable Trust and Oxford University to test and apply 'Pathways', a modelling framework and software tool which stemmed and evolved from the Pew report, at country level. The tool calculates the flows of plastics in the economy and the impact of various strategies to reduce future plastic pollution. The Scenario Builder within the Pathways tool allows the user to optimise flows in the plastics value chain to satisfy a set of defined objectives in order to achieve an optimal solution. Three major findings have emerged from the application of Pathways at country level for South Africa. Firstly, plastic pollution is set to almost double by 2040 if no interventions are implemented. Secondly, meeting the newly legislated extended producer responsibility (EPR) targets set for plastic packaging can avoid 33% of projected total pollution over the period of 2023-2040. Lastly, an optimal system change can avoid 63% of total plastic pollution over the period 2023-2040. Thus, applying Pathways at country level in South Africa has proven to be valuable by setting a baseline against which progress towards reducing plastic pollution can be measured; determining the outcome of meeting the legislated EPR targets over time, and informing policy decisions by allowing users to model different scenarios towards an optimal system change scenario.
Advancing sustainable port development in the Western Indian Ocean region
(2024-12) Taljaard, Susan; Weerts, Steven P; Audouin, Michelle A
The Western Indian Ocean (WIO) region is experiencing rapid growth in large-scale developments, including ports. These ports play an important role in the region’s economy, but they are invariably located in coastal areas with rich natural resources that provide other ecosystem-based societal benefits. Progress has been made towards greater port sustainability in the region in recent years, but there is an urgent need to accelerate regional sustainable efforts. In response, the Nairobi Convention Secretariat initiated the development of a ‘Toolkit for Sustainable Port Development’. This was rooted in an Integrated Port Management (IPM) framework comprising four key phases: planning, design, construction, and operations. A systematic and incremental approach is recommended for implementation, first adopting the IPM framework and then applying eco-friendly technologies and practices based on place-based priorities to reduce environmental impacts and unacceptable socio-economic consequences. This will contribute significantly to sustainable port development in the WIO region.
Advancing the science of environmental flow management for protection of temporarily closed estuaries and coastal lagoons
(2021-02) Stein, ED; Gee, EM; Adams, JB; Irving, K; Van Niekerk, Lara
The science needed to inform management of environmental flows to temporarily closed estuaries and coastal lagoons is decades behind the state of knowledge for rivers and large embayments. These globally ubiquitous small systems, which are often seasonally closed to the ocean’s influence, are under particular threat associated with hydrologic alteration because of changes in atershed land use, water use practices, and climate change. Managing environmental flows in these systems is complicated by their tight coupling with watershed processes, variable states because of intermittently closing mouths, and reliance on regional scale sediment transport and littoral processes. Here we synthesize our current understanding of ecohydrology in temporarily closed estuaries (TCEs) and coastal lagoons and propose a prioritized research agenda aimed at advancing understanding of ecological responses to altered flow regimes in TCEs. Key research needs include agreeing on a consistent typology, improving models that couple watershed and ocean forcing at appropriate spatial and temporal scales, quantifying stress–response relationships associated with hydrologic alteration, improving tools to establish desired conditions that account for climate change and consider cultural/indigenous objectives, improving tools to measure ecosystem function and social/cultural values, and developing monitoring and adaptive management programs that can inform environmental flow management in consideration of other stressors and across different habitat types. Coordinated global efforts to address the identified research gaps can help guide management actions aimed at reducing or mitigating potential impacts of hydrologic alteration and climate change through informed management of freshwater inflows.
An aerodynamic CFD analysis of inlet swirl in a micro-gas turbine combustor
(2023-07) Meyers, Bronwyn C; Grobler, Jan-Hendrik; Snedden, GC
A combustor was designed for a 200N micro-gas turbine [1, 2] using the NREC preliminary combustor design method [1, 2, 3]. During the design process, there are various aspects where there are no definitive methodologies for specifying the design detail, such as the design of the hole-sets, and multiple options can be derived that can satisfy the required mass flow split and pressure drop for a particular hole-set.
African case studies: Developing pavement temperature maps for performance-graded asphalt bitumen selection
(2022-01) Mokoena, Refiloe; Mturi, George AJ; Maritz, Johan; Mateyisi, Mohau; Klein, Pieter
The reliable performance of roads is crucial for service delivery, and it is a catalyst for domestic and cross-border spatial development. Paved national roads are expected to carry higher traffic volumes over time as a result of urbanization and to support the economic development in the continent. Increased traffic levels combined with expected increases in air temperatures as a result of global warming highlight the need to appropriately select bituminous road materials for a reliable performance of asphalt roads. The objective of the paper is to present African case studies on the development of temperature maps necessary for performance-graded bitumen selection for road design and construction. A consistent approach, that caters for the variability of geographical, environmental and climatic conditions, does not currently exist within the continent. Therefore, this paper discusses a series of critical components in the development of temperature maps for performance-graded bitumen including (i) pavement temperature models and climatic zones in Africa; (ii) the effect of urban heat islands on pavement temperature; (iii) sources of weather data and (iv) the mapping procedure to produce temperature maps. Characterizing the thermal properties of the pavement was found to be an important factor for reliably calculating expected road temperatures as well as the consideration of the ambient climate for a given location. During this study, the urban heat island effect was found to have little influence on the maximum pavement temperatures but a significant effect on the minimum pavement temperatures. Some areas of the urban district assessed in this investigation were found to increase by two performance grades according to the minimum temperature criteria. The recent observed weather data from weather stations are the most accurate means of measurement of the ambient environmental conditions necessary for performance-based specifications, but they are not always easily accessible, and therefore other sources of data, such as satellite data, may need to be used instead. With the expected temperature increases expected as a result of climate change, the use of Global Climate Models also opens new avenues for performance-based material selection in the African continent for expected climates as an alternative to traditional approaches based on historically observed weather.
Ammonium metal phosphates: Emerging materials for energy storage
(2020-06) Raju, Kumar
The search for new materials that can hold the heteroatoms viz., nitrogen, oxygen and phosphorus becomes crucial for robust energy storage and conversion devices. Recently, ammonium metal phosphates (NH4MPO4, M = Mn2+, Ni2+, Co2+, Fe2+, etc.) and their hydrates have emerged as promising materials because of their attractive virtues; rapid electron transport because of the existence of more electroactive sites; and highly redox-active centres and rapid ion transport because of the intercalated water interactions. The synthesis of different dimensionalities (0D–3D) of these materials is facile and robust that boosts the electrochemical performances to some extent. This review emphasises the recent state-of-the-art work published on the ammonium metal phosphates for energy storage and a brief discussion on key challenges and future directions.
Analysis of nighttime lights over the cities of Cape Town, Durban and Johannesburg, South Africa
(2024-01) Mncube, Z; Xulu, S; Mbatha, Nkanyiso B
Remote sensing of nighttime light (NTL) offers a unique and practical means of assessing human developments through snapshots of nocturnal lighting captured from space. The Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) is one of the widely used NTL products and is now publicly available on Google Earth Engine (GEE), which allows accelerated analysis using different geospatial approaches. Here, we perform a comparative trajectory analysis of NTL over the three largest cities of South Africa between 2014 and 2023, and project the changes for 2027 based on Markov chain analysis. Our results show that the NTL increased steadily for the city of Durban (from 27.93 nW cm−2.sr−1 in 2014 to 29.45 nW cm−2.sr−1 in 2023) but decreased in the cities of Cape Town (from 32.30 nW cm−2.sr−1 in 2014 to 31.14 nW cm−2.sr−1 in 2023) and Johannesburg (from 52.19 nW cm−2.sr−1 in 2014 to 46.82 nW cm−2.sr−1 in 2023). The unstable power supply of South African cities can affect the NTL data. In addition, from our results, a similar pattern for each of these cities is observed to be in line with load shedding events in the country, especially for Cape Town and Johannesburg. Regarding the spatiotemporal distribution of the NTL, the central areas have medium to high radiance and have been spreading to the periphery of the cities since 2014. Moreover, land use and land cover (LULC) analysis reveals that developed urban areas, shown by dense built-up areas, coincide with the locations of medium and high NTL radiances. The assessment of NTL changes across low, medium, and high classes indicates a stable configuration with no large changes between classes; this is also observed on the spatial projection of NTL for the year 2027. Our results shed light on NTL mapping in large cities, an area that is constantly evolving due to new developments in remote sensing.
Analysis of the determinants of household’s water access and payments among the urban poor. A case study of Diepsloot Township
(2022-10) Tshililo, FP; Mutanga, Shingirirai S; Sikhwivhilu, K; Siame, J; Hongoro, C; Managa, LR; Mbohwa, C; Madyira, DM
Currently, 91% of the world population has access to clean and safe water. Despite this encouraging development exclusion and marginalisation of the poor appear not only to be deepening but fast spreading. Low-income communities in urban areas are increasingly grappling with issues of reliability, sufficiency, and affordability of potable water. Attaining SDG 6 and its targets goal is a daunting task for most developing nations and limited evidence provide an intrinsic look at water systems for marginalised urban communities. This study investigates factors influencing household water access, its reliability and affordability among the low-income communities. The study administered a structured questionnaire to 500 households to determine key predictors of household water access. Findings show persistent high unemployment levels with most of the people surviving on less than R 3000 (198 USD) a month. Around 66% of households had access to tap water either inside the house or yard, but the water supply was irregular, and most households were not paying for the water. Household water access and payment for water services were influenced by house type, household size and water source with a p value of 0.00, 0.035 and 0.042 respectively. Other variables such as education, employment, and income were not significant predictors of household's water access. The study observed that income, employment, education, gender, drinking tap water, water interruptions, and satisfaction levels did not have a significant relationship with household water payment for water services. The findings of this study highlight the importance of policy in driving water service provision for the successful attainment of Sustainable Development Goal 6.1.
Antarctica and the Southern Ocean
(2024-08) Clem, KR; Raphael, MN; Adusumilli, S; Amory, C; Baiman, R; Banwell, AF; Barreira, S; Beadling, RL; Bozkurt, D; Thomalla, Sandy J
Antarctica experienced strong to record below-average pressure and stronger-than-average circumpolar westerlies to start (January) and close (December) 2023, marking the third and fourth consecutive summers with such conditions (2020/21, 2021/22, 2022/23, 2023/24). During austral autumn, winter, and spring, the atmospheric circulation over the South Pacific underwent a marked transition from the previous three years as the “triple dip” La Niña officially transitioned to El Niño during autumn 2023. Consistent with El Niño, positive pressure anomalies developed in the Ross and Amundsen Seas, and anomalous low pressure developed over the Antarctic Peninsula and western Weddell Sea. These two circulation anomalies produced two regions of persistent warm northerly flow and above-average atmospheric river activity: across the Weddell Sea and Dronning Maud Land (on the eastern side of the low) and in the Wilkes Land region (on the western side of the high). These two regions saw Antarctica’s most pronounced climate anomalies in 2023, including well-above average temperatures and surface mass balance. These anomalies were most pronounced in the Weddell Sea region where western Dronning Maud Land, Coates Land, and the Ronne-Filchner Ice Shelf saw Antarctica’s highest surface mass balance anomalies for the year, and temperatures for much of the year ranged from 2°C to 6°C above average over the Weddell Sea and along coastal Dronning Maud Land. The Antarctic Peninsula also experienced well-above-average temperatures and surface melting during the 2022/23 summer melt season, marking the fourth consecutive summer of anomalous high surface melt on the Peninsula.

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