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Review of tropical cyclones in the Australian region : Climatology, variability, predictability, and trends

- Chand, Savin, Dowdy, Andrew, Ramsay, Hamish, Walsh, Kevin, Tory, Kevin, Power, Scott, Bell, Samuel, Lavender, Sally, Ye, Hua, Kuleshov, Yuri

  • Authors: Chand, Savin , Dowdy, Andrew , Ramsay, Hamish , Walsh, Kevin , Tory, Kevin , Power, Scott , Bell, Samuel , Lavender, Sally , Ye, Hua , Kuleshov, Yuri
  • Date: 2019
  • Type: Text , Journal article , Review
  • Relation: Wiley Interdisciplinary Reviews: Climate Change Vol. 10, no. 5 (2019), p. 1-17
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  • Description: Tropical cyclones (TCs) can have severe impacts on Australia. These include extreme rainfall and winds, and coastal hazards such as destructive waves, storm surges, estuarine flooding, and coastal erosion. Various aspects of TCs in the Australian region have been documented over the past several decades. In recent years, increasing emphasis has been placed on human-induced climate change effects on TCs in the Australian region and elsewhere around the globe. However, large natural variability and the lack of consistent long-term TC observations have often complicated the detection and attribution of TC trends. Efforts have been made to improve TC records for Australia over the past decades, but it is still unclear whether such records are sufficient to provide better understanding of the impacts of natural climate variability and climate change. It is important to note that the damage costs associated with tropical cyclones in Australia have increased in recent decades and will continue to increase due to growing coastal settlement and infrastructure development. Therefore, it is critical that any coastal infrastructure planning and engineering decisions, as well as disaster management decisions, strongly consider future risks from tropical cyclones. A better understanding of tropical cyclones in a changing climate will provide key insights that can help mitigate impacts of tropical cyclones on vulnerable communities. An objective assessment of the Australian TCs at regional scale and its link with climate variability and change using improved and up-to-date data records is more imperative now than before. This article is categorized under: Paleoclimates and Current Trends > Modern Climate Change.

A review of the scaled boundary finite element method for two-dimensional linear elastic fracture mechanics

- Song, Chongmin, Ooi, Ean Tat, Natarajan, Sundararajan

  • Authors: Song, Chongmin , Ooi, Ean Tat , Natarajan, Sundararajan
  • Date: 2018
  • Type: Text , Journal article , Review
  • Relation: Engineering Fracture Mechanics Vol. 187, no. (2018), p. 45-73
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  • Description: The development and the application of the scaled boundary finite element method for fracture analysis is reviewed. In this method, polygonal elements (referred to as subdomains) of arbitrary number of edges are constructed, with the only limitation that the whole boundary is directly visible from the scaling centre. The element solution is semi-analytical. When applied to two-dimensional linear fracture mechanics, any kinds of stress singularities are represented analytically without local refinement, special elements and enrichment functions. The flexibility of polygons to represent arbitrary geometric shapes leads to simple yet efficient remeshing algorithms to model crack propagation. Coupling procedures with the extended finite element method, meshless method and boundary element method to handle changes in the crack morphology have been established. These developments result in an efficient framework for fracture modelling. Examples of applications are provided to demonstrate their feasibility. © 2017 Elsevier Ltd

Challenges faced by shorebird species using the inland wetlands of the East Asian-Australasian Flyway : The little curlew example

- Bellio, Mariagrazia, Minton, Clive, Veltheim, Inka

  • Authors: Bellio, Mariagrazia , Minton, Clive , Veltheim, Inka
  • Date: 2017
  • Type: Text , Journal article , Review
  • Relation: Marine and Freshwater Research Vol. 68, no. 6 (2017), p. 999-1009
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  • Description: Asia is experiencing an alarming rate of inland wetlands loss, posing a risk to the future long-term survival of many species depending on these ecosystems. This review on the status and conservation of the little curlew (Numenius minutus) aims to draw attention to the conservation challenges faced by migratory shorebird species using the inland wetlands of the East Asian-Australasian Flyway (EAAF). Extensive and systematic research survey efforts along the EAAF have focused on species using coastal and tidal areas rather than on species using inland wetlands. Knowledge gaps include functional ecology and physiological responses to quality of food resources, population trends, migratory strategy and the role species play in supporting ecosystems resilience. Studies using remote sensing and geographic information system techniques to track the movements of birds along the flyway and to map habitat condition will prove essential in the future to allow a better understanding of the dynamics occurring at the stopover areas, how birds use resources and what competition pressures exist among species. Ultimately, these studies will contribute to our ability to predict changes and establish management practices for the long-term protection and conservation of the stopover areas for a suite of shorebird species using inland wetlands along the flyway. © CSIRO 2017.

Lost in optimisation of water distribution systems? A literature review of system operation

- Mala-Jetmarova, Helena, Sultanova, Nargiz, Savic, Dragan

  • Authors: Mala-Jetmarova, Helena , Sultanova, Nargiz , Savic, Dragan
  • Date: 2017
  • Type: Text , Journal article , Review
  • Relation: Environmental Modelling and Software Vol. 93, no. (2017), p. 209-254
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  • Description: Optimisation of the operation of water distribution systems has been an active research field for almost half a century. It has focused mainly on optimal pump operation to minimise pumping costs and optimal water quality management to ensure that standards at customer nodes are met. This paper provides a systematic review by bringing together over two hundred publications from the past three decades, which are relevant to operational optimisation of water distribution systems, particularly optimal pump operation, valve control and system operation for water quality purposes of both urban drinking and regional multiquality water distribution systems. Uniquely, it also contains substantial and thorough information for over one hundred publications in a tabular form, which lists optimisation models inclusive of objectives, constraints, decision variables, solution methodologies used and other details. Research challenges in terms of simulation models, optimisation model formulation, selection of optimisation method and postprocessing needs have also been identified. © 2017

Risk of post-fire metal mobilization into surface water resources : A review

- Abraham, Joji, Dowling, Kim, Florentine, Singarayer

  • Authors: Abraham, Joji , Dowling, Kim , Florentine, Singarayer
  • Date: 2017
  • Type: Text , Journal article , Review
  • Relation: Science of the Total Environment Vol. 599-600, no. (2017), p. 1740-1755
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  • Description: One of the significant economic benefits to communities around the world of having pristine forest catchments is the supply of substantial quantities of high quality potable water. This supports a saving of around US$ 4.1 trillion per year globally by limiting the cost of expensive drinking water treatments and provision of unnecessary infrastructure. Even low levels of contaminants specifically organics and metals in catchments when in a mobile state can reduce these economic benefits by seriously affecting the water quality. Contamination and contaminant mobility can occur through natural and anthropogenic activities including forest fires. Moderate to high intensity forest fires are able to alter soil properties and release sequestered metals from sediments, soil organic matter and fragments of vegetation. In addition, the increase in post-fire erosion rate by rainfall runoff and strong winds facilitates the rapid transport of these metals downslope and downstream. The subsequent metal deposition in distal soil and water bodies can influence surface water quality with potential impacts to the larger ecosystems inclusive of negative effects on humans. This is of substantial concern as 4 billion hectares of forest catchments provide high quality water to global communities. Redressing this problem requires quantification of the potential effects on water resources and instituting rigorous fire and environmental management plans to mitigate deleterious effects on catchment areas. This paper is a review of the current state of the art literature dealing with the risk of post-fire mobilization of the metals into surface water resources. It is intended to inform discussion on the preparation of suitable management plans and policies during and after fire events in order to maintain potable water quality in a cost-effective manner. In these times of climate fluctuation and increased incidence of fires, the need for development of new policies and management frameworks are of heighted significance. © 2017 Elsevier B.V.

A review of practical tools for rapid monitoring of membrane bioreactors

- Scholes, Emily, Verheyen, Vincent, Brook-Carter, Phillip

  • Authors: Scholes, Emily , Verheyen, Vincent , Brook-Carter, Phillip
  • Date: 2016
  • Type: Text , Journal article , Review
  • Relation: Water Research Vol. 102, no. (2016), p. 252-262
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  • Description: The production of high quality effluent from membrane bioreactors (MBRs) arguably requires less supervision than conventional activated sludge (CAS) processes. Nevertheless, the use of membranes brings additional issues of activated sludge filterability, cake layer formation and membrane fouling. From a practical standpoint, process engineers and operators require simple tools which offer timely information about the biological health and filterability of the mixed liquor as well as risks of membrane fouling. To this end, a range of analytical tools and biological assays are critically reviewed from this perspective. This review recommends that Capillary Suction Time (CST) analysis along with Total Suspended and Volatile Solids (TSS/VSS) analysis is used daily. For broad characterisation, total carbon and nitrogen analysis offer significant advantages over the commonly used chemical and biological oxygen demand (COD/BOD) analyses. Of the technologies for determining the vitality of the microbial biomass the most robust and reproducible, are the second generation adenosine-5'-triphosphate (ATP) test kits. Extracellular polymer concentrations are best monitored by measurement of turbidity after centrifugation. Taken collectively these tools can be used routinely to ensure timely intervention and smoother operation of MBR systems. © 2016 Elsevier Ltd.

Dealing with Trade-Offs in destructive sampling designs for occupancy surveys

- Canessa, Stefano, Heard, Geoffrey, Robertson, Peter, Sluiter, Ian

  • Authors: Canessa, Stefano , Heard, Geoffrey , Robertson, Peter , Sluiter, Ian
  • Date: 2015
  • Type: Text , Journal article , Review
  • Relation: PLoS ONE Vol. 10, no. 3 (2015), p. e0120340
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  • Description: Occupancy surveys should be designed to minimise false absences. This is commonly achieved by increasing replication or increasing the efficiency of surveys. In the case of destructive sampling designs, in which searches of individual microhabitats represent the repeat surveys, minimising false absences leads to an inherent trade-off. Surveyors can sample more low quality microhabitats, bearing the resultant financial costs and producing wider-spread impacts, or they can target high quality microhabitats were the focal species is more likely to be found and risk more severe impacts on local habitat quality. We show how this trade-off can be solved with a decision-theoretic approach, using the Millewa Skink Hemiergis millewae from southern Australia as a case study. Hemiergis millewae is an endangered reptile that is best detected using destructive sampling of grass hummocks. Within sites that were known to be occupied by H. millewae, logistic regression modelling revealed that lizards were more frequently detected in large hummocks. If this model is an accurate representation of the detection process, searching large hummocks is more efficient and requires less replication, but this strategy also entails destruction of the best microhabitats for the species. We developed an optimisation tool to calculate the minimum combination of the number and size of hummocks to search to achieve a given cumulative probability of detecting the species at a site, incorporating weights to reflect the sensitivity of the results to a surveyor's priorities. The optimisation showed that placing high weight on minimising volume necessitates impractical replication, whereas placing high weight on minimising replication requires searching very large hummocks which are less common and may be vital for H. millewae. While destructive sampling methods are sometimes necessary, surveyors must be conscious of the ecological impacts of these methods. This study provides a simple tool for identifying sampling strategies that minimise those impacts. © 2015 Canessa et al.
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