Summer Scholarship Projects- 2017/18

UNSW

Australian vegetation dynamics: the role of water (based at UNSW)

Supervised by: Dr Anna Ukkola and Dr Martin De Kauwe

Australia is the driest inhabited continent with marked inter-annual variability in rainfall. This variability in water availability is a key determinant for ecosystem function. To improve future projections of vegetation-climate interactions, it is crucial to understand the underlying mechanisms controlling vegetation responses to water availability. This project aims to develop a better quantitative understanding of how plants respond to varying water availability by contrasting satellite-derived observations with simulations from the Australian community land surface model, CABLE. Some programming experience in Python, R or similar is desirable.

Exploring the mid-Holocene Green Sahara (based at UNSW)

Supervised by: Professor Steve Sherwood and Dr Vishal Dixit

The African Sahara could be the largest art gallery on Earth, showcasing thousands of engravings and cave paintings.  Desert today, it was covered with plants around 5000 years ago.  Climatic shifts had tremendous impact on African civilization and continue to be a threat to the Sahel region south of the Sahara, which experienced a multi-decadal drought during the latter half of the 20th century. The explanation for these shifts remains an enigma.  One idea is that mid-level drying inhibits precipitating convection in the region. In this project the student will analyse the decadal co-variations of mid-level drying and convection to test this idea, using global observation-based datasets.  The student should have a basic understanding of atmospheric processes, and some knowledge of data manipulation software is helpful.

Physical drivers of extreme marine heat waves (based at UNSW)

Supervised by: Dr Alex Sen Gupta, Dr Angela Maharaj and Dr Markus Donat

Marine heat waves can have a dramatic effect on marine species with often important implications for fisheries and aquaculture. Yet compared to their terrestrial counterparts only a handful of marine heat waves have been examined in detail to understand the physical processes that generate these events. In this project we will use observations of sea surface temperature in combination with hybrid observation/model dats sets of the subsurface ocean to 1. identify a major marine heat wave that has not been investigated in detail, 2. identify the local process (both oceanographic and atmospheric) that generated the event and 3. examine how the heatwave is affected by large scale climate oscillations (like El Nino and La Nina).

Siting of instruments for urban climate and air quality research in Sydney (based at UNSW)

Supervised by: Dr Melissa Hart, Dr Angela Maharaj and Dr Giovanni Di Virgilio

Sydney’s population is predicted to grow by 30% within twenty years, most of which is slated for the semi-rural fringes. The resulting urbanisation will adversely impact temperature and air quality in these areas of rapid population growth. Currently there are few meteorological and air quality observational sites to adequately monitor the effects of this increased urbanisation on local weather and air quality. The Sydney Schools Weather and Air Quality (SWAQ) network aims to place instruments in Sydney schools to fill these gaps. A student with GIS knowledge and interest in urban environmental monitoring is required to consolidate information on existing monitoring sites, identify keys areas of development and projected population growth to produce a list of optimal monitoring sites in the greater Sydney region and surrounds. 

Australian east coast lows in satellite wind data  (based at UNSW)

Supervised by: Dr Alejandro Di Luca and Associate Professor Jason Evans

Extra-tropical cyclones can be identified using a variety of 2-dimensional fields including mean sea level pressure, relative vorticity (e.g. at 850 hPa) and/or geopotential heights (e.g. 925 hPa). While all these fields provide appropriate characteristics and yields qualitatively similar results, they are all poorly constrained by observations, particularly over the oceans. As a consequence, results are sometimes largely dependent on the specific model used by the reanalysis product. For example, Australian East Coast Lows (ECLs) spend much of their life-time over the ocean where measurements of sea level pressure do not exist and substantial variation between different reanalysis can occur.

This project will implement an algorithm to identify ECLs using only surface wind fields as derived from satellite measurements. These results can then be used to evaluate the representation of ECLs in reanalysis products and to compare with results obtained using other meteorological fields. A number of cyclones characteristics will be used in the evaluation process such as their frequency, size and translation speed.

Modes of variability in Southern Hemisphere climate and oceans (based at UNSW)

Supervised by: Dr Agus Santoso

This project will examine particular features of Southern Hemisphere climate and oceans variability using observations and climate models.   The student will have the option to focus on a particular aspect of interest, such as processes associated with the El Nino Southern Oscillation or the Indian Ocean Dipole, or their extreme behaviour, just to name a few.   There will also be scope to extend the analysis to future projections under greenhouse forcing.  Other than learning about climate dynamics, the student will also gain skill in processing large data sets, conducting statistical analysis, and programming with Matlab.   

Where's NEMO now? Dynamics of the East Australia Current (based at UNSW)

Supervised by: Dr Alejandro Di Luca and Dr Paul Spence

The East Australia Current (EAC), made famous by the movie Finding Nemo, runs southward along the east coast of Australia. It is a highly variable current that transports an enormous amount of heat from the tropics to the Tasman Sea, and shapes Australia's climate by influencing the location and intensity of storms. The aim of this project is to quantify the ability of ocean models with a varying level of complexity to simulate key characteristics of the EAC (e.g. volume transport, heat transport, nutrient transport). The student will learn to handle big data, develop valuable Python programming skills, and understand the role of the EAC in Australian climate.

Assessing future changes in extreme surface fire weather and atmospheric instability (based at UNSW)

Supervised by: Dr Giovanni Di Virgilio and Associate Professor Jason Evans

Extreme bushfires occur under conditions of extreme surface fire weather and atmospheric instability that facilitates coupling between the fire and atmosphere, often generating pyro-cumulonimbus events. Several studies have been performed that investigated future changes in surface fire weather (often using the Forest Fire Danger Index, FFDI) and generally find an increase particularly in the transition seasons. Few studies have investigated the occurrence of severe atmospheric instability (using the continuous Haines index – cHaines). This project will investigate coincident occurrence of extreme FFDI and cHaines, its relationship with large fires, and how it will change in the future.

Optimization:  Can land surface models benefit from adapting current practices in hydrological models? (based at UNSW)

Supervised by: Dr Mark Decker and Professor Andy Pitman

Land surface models (LSMs) comprise the terrestrial component of weather and climate prediction systems.  Based on simplifying assumptions and reduced complexity representations of the physical processes, LSMs simulate the storage water, energy, and carbon within the soil, snow, and vegetation, as well as the transfer between the land and the atmosphere.  The land surface plays a crucial role in initiating thunderstorms and clouds, determining the near surface air temperature, and governing the severity of droughts.  LSMs stand distinct from global hydrological models (GHMs) because LSMs emphasize the transfer of energy, water, and chemicals between the land and the atmosphere and GHMs emphasize the flow of water in soils, rivers, and lakes.  Despite different focusses both  LSMs and GHMs simulate the terrestrial hydrological cycle.  However LSMs and GHMs approach model calibration in fundamentally different ways.  GHMs explicitly recognize the unobservability and uncertainty of model parameters and combine complex optimization algorithms with limited observations to find the optimum parameter values.  In contrast, LSMs neglect formal optimization and rely on hand tuning unkown parameters.  The benefit of optimization for GHMs is readily apparent even though parameter optimization is limited to data rich regions.  The LSM community generally neglects optimization when data is available due to the lack of observations over much of the globe.

This study will examine the efficacy of optimizing a LSM at several sites, and determine the transferability of the optimum parameters to sites with similar vegetation and climatology.  The land surface component of the Australian climate model (ACCESS), CABLE, will by optimized at several sites using observed fluxes of water and energy.  The transferability of the optimum parameters to sites with similar vegetation and climatology will be evaluated by using the optimized parameters at sites not used during the optimization.  This study will demonstrate if the LSM community is correct in neglecting optimization where the data are available because the models are utilized globally.

The student will conduct model simulations using default, optimized, and random parameter values.  This project involves the use of Linux systems, computer models, and model output analysis.  The ideal student will have some experience or interest in programming and visualization, for example with Python, NCL,or R.  The chosen scholar will gain expertise in handling real world data, using the land component of weather and climate models, and model output analysis.

Estimating sensitivity in a variable climate (based at UNSW)

Supervised by: Dr Leela Frankcombe

The amount by which our climate will warm depends on the amount of greenhouse gases we emit as well as how sensitive the climate system is to those greenhouse gases. This 'climate sensitivity' is estimated from climate models or from observations of the real climate (either from the distant past or from the more recent historical period). When using resent observations we have to take into account the role of natural climate variability in order to make accurate estimates of climate sensitivity. 
 
This project will use a highly idealised framework to study the effect of different types and amplitudes of climate variability on the estimation of climate sensitivity. Using the results from this project we aim to learn the optimum method of estimating  sensitivity in a variable climate as well as the errors associated with that estimation.  
 
Prior experience with a programming language is not required, but potential students must be willing to learn programming skills for the project.

UTas

Antarctic Bottom Water change at Heard Island (based at UTas)

Supervised by Dr Helen Phillips

In January 2016, we conducted a hydrographic survey of watermass properties and velocity structure east of Heard Island aboard RV Investigator. This cross-shore transect from deep water up onto the shelf captured Antarctic Bottom Water at one point along its journey from the Antarctic coast into the Indian Ocean. This project will map the properties of AABW at this one point in time, and compare it with earlier observations in the same region. This work will provide new estimates of change in AABW in response to climate change. These observations will contribute to a larger project that will examine AABW change observed simultaneously at 5 locations along its Southern Ocean pathway.

Subtropical Front dynamics in the Tasman Sea and its biogeochemical implications (based at UTas)

Supervised by: Dr Joan Llort and Associate Professor Pete Strutton

The Tasman Sea is the small ocean basin enclosed between Australia and New Zealand. The southern half of this basin is characterised by a complex circulation with warm tropical and sub-tropical waters encountering sub-Antarctic waters from the Southern Ocean. The dynamic barrier between these two water masses is known as the Subtropical Front (STF, see figure below). The location of the STF has important consequences for the biogeochemistry in the Tasman Sea because it segregates the nutrient-poor northern waters with the nutrient-rich (but iron-low) waters from the Southern Ocean. The aim of this project is to determine the position of the STF during the last 15-20 years using observational data, such as Argo floats and satellite data (altimetry and ocean colour data). The results from this work will provide the context to understand the observed changes in phytoplankton activity in the Tasman Sea during the last 20 years.  

Southern Ocean Clouds, Radiation and Aerosol Transport Experimental Studies (SOCRATES) field experience

Supervised by: Dr. Simon Alexander, Dr. Yi Huang and A/Prof Steve Siems 

SOCRATES is an international field campaign being based out of Hobart this summer for six weeks. (~ 12 January to 24 February).  The US National Science Foundation is deploying a research aircraft (the NCAR G-V HIAPER) to make unprecedented observations of the pristine clouds over the remote Southern Ocean to address the significant cloud and radiation biases in climate models over this region.  Some flights will be coordinated with ship-based surface observations being made onboard the Australian R/V Investigator.  We seek a summer student to assist in data quality control, instrumentation maintenance and public outreach. This project presents a unique opportunity for a student to gain valuable experience in science communication and public outreach, while also expanding their research skill set through data quality control tasks and hands-on instrument experience.

UMelb

Unique aerosol measurements over the Great Barrier Reef (based at UMelb)

Supervised by: Dr Claire Vincent, Dr Robyn Schofield, Dr Alain Protat

In this project, the student will analyse and compare two unique observational datasets of aerosols over the Great Barrier Reef. Both datasets were collected during a voyage of the CSIRO Research vessel, the RV Investigator, in 2016.

The first dataset consists of measurements collected from instruments that were suspended from an enormous, helium filled balloon that was winched up and down through the atmosphere, to a height of about 600m. This was the first time such measurements had been collected over the sea. The second dataset consists of high quality measurements remotely sensed from a LiDAR onboard the ship. Together, the data will tell us about the quality of the air and sources of pollution and other aerosols around the Great Barrier Reef. 

Like most observational data, the measurements contain missing values, systematic errors and significant uncertainties. Your job is to reveal the fascinating science contained in the data through careful analysis and creative plotting. Programming experience, preferably with MATLAB, IDL, R or PYTHON is essential for this project.

Impact of changing climate on Southern hemisphere tropical cyclone formation rates (based at University of Melbourne)

Supervised by: Professor Kevin Walsh and Dr Sharmila Sur

Tropical cyclones (TCs) are often catastrophic high-impact weather events, and trigger high mortality and huge economic damage in populated tropical coastal regions. Although widely debated, there is a growing recognition that the ongoing warming trends over the tropical oceans can drastically complicate the status and fate of global TC activity. Understanding the altering behaviour of TC activity in a changing climate is thus a topic of profound socio-economic significance. However, how TC formation rates have changed in recent decades or will change in warmer climate still remains challenging and uncertain. A better understanding of the warming-induced underlying physical mechanisms that regulate TC formation rates will be crucial for improving our knowledge of future TC estimates.

The goal of this project is to investigate the relationship between the changing large-scale tropical environment and TC formation rates in recent decades, in particular over the southern hemisphere. Based on the latest best-track datasets, modern reanalyses and standard statistical methods, the student will identify the dominant tropical climate conditions that have significantly modulated TC formation rates over southern hemisphere. A particular focus will be on the 2016-2017 TC season and the climate-related reasons for the very late start to the TC season in our region.

            In this project, the student will have the opportunity to develop better technical skills in handling and analysing large datasets. Depending on the progress and interest of the student, there is an opportunity to write up their results for a peer-reviewed publication. The project is suitable for a student with a basic understanding of climate processes, and some experience with Unix computing. Previous knowledge of Python, Matlab, NCL or GrADS would be highly beneficial.

ANU

The dynamics of wind-forced internal waves (based at ANU)

Supervised by: Dr Callum Shakespeare

The ocean is a sea of internal gravity waves. Similar to the gravity waves that propagate over the ocean surface and break along our coastlines, internal waves propagate great distances through the ocean interior. These waves are vital for deep ocean mixing and the maintenance of the ocean’s overturning circulation. The two largest sources of internal waves are high-frequency wind stresses acting on the ocean surface and tides flowing over the rough seafloor. Tidal generation is a well studied problem, but the dynamics by which wind stresses drive the generation of internal waves is less so. In this project we will investigate thie wind generation problem using an idealised numerical model of the upper ocean. We will determine how the energy, frequency and scale of wind-generated internal waves depends on the wind stress forcing and the properties of the ocean itself. 
 
This project would suit students with a physics, maths or fluid dynamics background and an interest in ocean modelling. 

CSIRO (Aspendale)

Relationships between stratospheric ozone depletion, chlorine and polar clouds in models and observations (based at CSIRO)

Supervised by: Dr Matt Woodhouse, Dr Robyn Schofield and Dr Andrew Klekociuk

Stratospheric ozone depletion (the ozone hole) is the direct result of anthropogenic chlorine emission (e.g. chloroflourocarbons, CFCs). Stratospheric ozone is destroyed by reactive chlorine, which is itself produced within polar stratospheric clouds (PSCs) from CFCs. Ozone is a greenhouse gas, and the ozone hole has a direct impact on Southern Hemisphere climate and winds, reinforcing some of the climate effects resulting from greenhouse gas emissions over recent decades. It is therefore highly desirable to accurately represent stratospheric ozone (and its depletion) in climate models so that we may better predict the state of the climate in coming decades.

In this project, polar stratospheric clouds, stratospheric reactive chlorine and stratospheric ozone from state of the art model simulations will be evaluated against real-world observations to identify biases within the model. The student will also quantify the sensitivity of ozone loss to reactive chlorine and polar stratospheric clouds, both in models and in observations, the first time such a study has been attempted.

The student will conduct the analysis in a unix supercomputing environment using Matlab, IDL, python or a similar language. Demonstrated programming and data analysis skills are highly desirable, though the student can expect to acquire new skills and knowledge during the project with the input of the supervisors. The student will be based at CSIRO Aspendale, and will be supervised by Dr. Matt Woodhouse (CSIRO), Dr. Robyn Schofield (University of Melbourne), and Dr. Andrew Klekociuk (Australian Antarctic Division).

Monash

Applicants for this project should apply through the Monash summer research scholarship scheme (applications close October 7).

Understanding trends in tropical upper-tropospheric temperature (based at Monash)

Supervised by Dr Martin Singh

Climate models predict that the temperature of the tropical upper troposphere will warm faster than the surface in response to increased greenhouse-gas concentrations. However, this upper tropospheric “amplification" of warming is weaker or not present in many observational datasets. Furthermore, the degree of amplification varies substantially across different climate models used in the IPCC assessments. This project will seek to understand the origin of these differences by examining the output of climate models and comparing this output to a simple theoretical prediction for the tropical temperature profile. The student will examine to what extent different assumptions used in the theoretical model can explain the different amplification factors among climate models.

Exploring relationships between lightning, radar-derived hail diagnostics, and hail damage (based at Monash)

Supervised by Dr Rob Warren

Severe hail storms represent a major hazard along the central east coast of Australia, with previous events causing billions of dollars in damage. Knowledge of the climatology of these storms is thus of great value to both forecasters and the insurance industry. Previous work has shown that radar-derived diagnostics, such as the maximum expected size of hail (MESH), provide a good indication of whether or not damaging hail will occur. A question which has yet to be addressed is whether these diagnostics can predict the severity of hail damage. Furthermore, since radar coverage is confined to major cities there is a need to investigate the potential of other hail predictors, such as lightning flash count. In this project we will attempt to address these issues using three unique datasets which have been developed for the Brisbane and Sydney regions. These consist of gridded fields of lightning flash count, MESH, and hail damage insurance claims for a total of 70 days (31 in Brisbane and 39 in Sydney). Relationships between the variables will be explored using a combination of neighbourhood processing and regression analysis.

Reassessing the initiation and predictability of El Nino events (based at Monash)

Supervised by Dr Shayne McGregor

El Nino events have dramatic impacts on climate and extreme weather around the globe, including floods, droughts and tropical cyclone formation and landfall. While many institutions around the globe offer routine forecasts of these events, the events continue to surprise the experts and defy forecasts. This is despite the improvement in our understanding, numerical models and observations of the tropical Pacific region. This apparent unpredictability is largely thought to stem from the stochastic nature of the event initiation. This study will use a series of atmospheric model simulations to investigate the whether any of the nature of this stochastic forcing and its relationship to background SSTs.

 

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