Research Topic: Modelling non-stationarity in rainfall-runoff relationships in Australia catchments
Australia (particularly southeast Australia) has experienced several multi-year droughts in the past. These droughts have resulted in emptying reservoirs and associated water mismanagement. One major cause of the mismanagement is due to the unrealistic water estimated by existing rainfall-runoff models used for water availability estimation. These models fail due to their simplistic structure where they do not account for several catchment mechanisms which drive the rainfall-runoff non-stationarity (i.e. runoff generated per unit rainfall in a catchment are different for contrasting climatic periods i.e. wet or dry). Proloy’s research investigates several catchment and climate associated mechanisms which govern the rainfall-runoff non-stationarity and include them into a robust framework of existing models for a realistic runoff simulation under rainfall-runoff non-stationarity.
Two of the mechanisms which govern the rainfall-runoff non-stationarity are land use change and surface water-groundwater interactions. The land use change is generally accounted for in the rainfall-runoff models, however, the surface water-groundwater interaction is not, and therefore, Proloy has developed and tested a new linked surface water-groundwater modelling approach which considers a rainfall-runoff model and a groundwater model and simulates the runoff. Proloy has also done a comparative study of models prior to selecting the appropriate rainfall-runoff and the groundwater models. His results indicate a significant improvement in runoff simulation under rainfall-runoff non-stationarity while using the linked surface water-groundwater modelling approach compared to stand-alone rainfall-runoff model simulated results. These findings will be highly applicable for proper water management under hydroclimatic variability in Australian catchments.
Proloy is supervised and co-supervised by Associate Prof. Anthony Kiem and Professor Garry Willgoose respectively, and he is close to the end of his PhD.
Research Topic: Palaeoclimate reconstructions from geologic archives from the Cook Islands (South Pacific)
The climate of the South Pacific is highly variable, acting in response to large-scale ocean-atmosphere systems over varying temporal scales. However, the instrumental records in this region are typically short and incomplete, providing only a snap-shot of the range of conditions this region experiences. Further, Global Climate Models (GCMs) provide an inconsistent projection of future changes, hampering response planning to anthropogenic climate change. Much of this uncertainty is due to the wide ranging projections for changes in the South Pacific Convergence Zone (SPCZ), a major driver of rainfall variability for the region. My project aims to address these knowledge gaps by providing a reconstruction of past 2000 years of rainfall variability from stalagmites and interpret such variability in terms of shifts in the South Pacific Convergence Zone (SPCZ). In the last three decades, speleothems (caves secondary calcium carbonate deposits) have become a cornerstone of approach to better understanding Earth’s climate because they capture the cave’s response to the external environment. This response is encoded in the form of chemical and physical characteristics, which act as proxies of palaeoclimate. Any speleothem-based research in unchartered territory, like Southern Cook Islands, must be based on monitoring the current status within caves. Here, this baseline is used to benchmark the interpretation of paleoclimate signals encoded in stalagmites of last 2000 years on the basis of monitoring the current cave conditions. A wide range of proxies such as oxygen and carbon stable isotopes, and trace elements are available for modern deposits which will be benchmarked against monitoring data and crystallization pathways. This will be followed by propagating the interpretation to stalagmites to reconstruct the paleoclimate of last 2000 years. A particular strength of this research is using calcite fabrics such that unconventional calcite farming data will be used to solve uncertainties associated with interpretation of other proxies. Importantly, the reconstruction can assist in evaluating GCMs and provide an improved understanding of the baseline climate.
Research Topic: Submarine landslides along the east Australian continental margin and the tsunami hazard they pose for the east Australian Coastline’
Submarine landslides are considered to be a common characteristic of the east Australian continental margin. However, their sedimentology and tsunamigenic potential is not well understood. This project aims to investigate the sedimentology and identify the likely age of several submarine landslide sites located along the east Australian continental margin. Hydrodynamic modelling of landslide failure will also be undertaken to better understand how these landslides fail and the potential tsunami hazard that they pose to the east Australian coastline.
Research Topic: Identification of rare earth element phase associations in Australian coal by-products and the potential for their extraction
In recent years, there has been a global recognition of the importance rare earth elements (REEs) have for the development and production of many high-tech devices and renewable energy technologies. For example, the REEs are utilised in: magnets used in wind turbines, nickel-metal hydride (NiMH) batteries for hybrid electric vehicles, and phosphors used in mobile phone and laptop displays. The term REE most commonly refers to the lanthanide series of elements (Z=57-71), and includes yttrium (Y) and scandium (Sc) due to their similar chemical properties and common occurrence in rare earth minerals. Currently, greater than 86% of rare earth production and 50% of known reserves occur in China. However, steady growth in demand has restricted Chinese exportation, which resulted in the REE supply crisis of 2010 and subsequent price spike in 2011. Although the geopolitical leverage of China over western nations has since decreased, it still has a near monopoly on the global rare earth market.
Following numerous studies aimed at characterising REEs in US coal byproducts, pilot- and bench-scale projects have been established to produce high-purity REE concentrates. Despite promising initial results in the US, there are no detailed investigations into the rare earth resource potential of coal byproducts produced in Australia. In order to address this knowledge gap, my research aims to quantify the content and distribution of the REEs in coal tailings and combustion residues representing a diverse range of coal ages, ranks and depositional histories around Australia. Primary REE-bearing phases will be identified in the most economically promising samples, and the potential implications for their extraction will be evaluated based on elemental and mineralogical associations. These research goals will be met using a range of laboratory based methods, and advanced techniques such as Synchrotron Radiation based Micro X-ray Fluorescence (SR-XRF) to produce high spatial resolution elemental images. The establishment of a domestic source of REEs in coal by-products would see that Australia stands to benefit economically during the forecasted price surge, maintain its place in the growing market for high-value minerals, and improve the environmental profile of power generators through the evaluation of waste processing options.
Research Topic: Characterising and attributing variability of tropical cyclone tracks in the Southwest Pacific
The Southwest Pacific is a vast ocean region that is home to 15 island nations with diverse cultures. Of all natural hazards, tropical cyclones are the most destructive, causing significant impacts to properties, lives and infrastructure. To improve the resilience of societies to the destructive impacts of tropical cyclones, accurate forecasting is needed on timescales of seasons, through to weeks/days following tropical cyclone formation. However, accurate forecasts of tropical cyclone movement (i.e. track) post-formation is challenging due to uncertainties in the subsequent tropical cyclone position and intensity, which hampers the coordinated response to the risk. Thus, an effective warning and response strategy established at the time of initial threat requires an enhanced understanding of the characteristics of these intense storms.
My current research is concerned with the investigation of the impact of climate variability on tropical cyclone activity in the Southwest Pacific region. Moreover, it is aimed to develop robust adaptation strategies so that forecasting is more constrained, and the public adopts the predicted impacts. Thus, by looking at the large-scale interaction between the ocean and atmosphere, my research aims to better our understanding of tropical cyclone track variability in this region. The outcomes of this research will be an improved understanding of the drivers of tropical cyclones in the Southwest Pacific region. Identifying how the various drivers modulate tropical cyclones will enhance the ability to forecast such events given that many of the large-scale drivers (e.g. El Niño and La Niña) can be predicted up to 6 months in advance. This is particularly significant given the vulnerability of the study region to changes in the frequency and intensity of tropical cyclones making landfall. Hence, the information gained from this study will be beneficial in improving adaptive capacity to such events, especially on longer timescales.