Eastern Seaboard Climate Change Initiative – East
Coast Lows Project
Project Eastern Seaboard Climate Change Initiative – East Coast Lows Project
Project Manager: Peter Smith
Ph: 9895 6177 E: firstname.lastname@example.org
Project Coordinator: Graham Turner
Ph: 9585 6941 E: email@example.com
1.0 Summary........................................................................................................................ 2
2.0 Background and Objectives......................................................................................... 3
2.1 The Eastern Seaboard Climate Change Initiative ........................................................ 5
2.2 ESCCI East Coast Lows Program ............................................................................... 5
3.0 Research Plans ............................................................................................................. 7
Research Plan ESCCI-ECL project 1 East Coast Lows Hazard Tool ................................ 7
Research Plan ESCCI-ECL Project 2 Projections of future ECL frequency along the NSW
coast ................................................................................................................................ 14
Research Plan For ESCCI-ECL Project 3 Long term natural variability and probability
assessment of ECLs ....................................................................................................... 17
Research Plan For ESCCI-ECL Project 4 Coastal System Response and Probabilistic
Risk Assessment of Extreme East Coast Low Sequences .............................................. 19
Research Plan for ESCCI- ECL Project 5 : The Influence of ECL on the Water Security of
Coastal NSW ................................................................................................................... 22
1.1 ESCCI East Coast Lows Project
East Coast Lows (ECLs) are intense low-pressure systems which occur off the eastern coast of
Australia. They often intensify rapidly overnight, making them one of the more dangerous weather
systems to affect the NSW coast. ECLs can generate
gale force winds along the coast and adjacent waters,
heavy and widespread rainfall, leading to flash and/or major river flooding, and
very rough seas and prolonged heavy swells over coastal and ocean waters, which can
cause damage to the coastline and islands such as Lord Howe Island.
The June 2007 “Pasha Bulker” storm near Newcastle
was an East Coast Low. The behaviour of this weather
pattern is not well understood, but may have a
dramatic effect on the way climate change is
experienced on the east coast of Australia and across
The NSW Environmental Trust has agreed to fund a
$750,000 three year (minimum) research project on
understanding the formation and impacts of East Coast
Photo G.Turner Lows and how their frequency and intensity may alter
with climate change. ESCCI research partners expect
to use this money to leverage an additional $1-3 million. This project includes 6 sub projects which
to date are all on schedule in accordance with the approved Business Plan (Table 1).
Table 1. Progress on ESCCI East Coast Lows projects
Project Description Progress Details
1 A publicly accessible Eastern On track, Work completed on:
Seaboard Climate Hazard Tool development Collation of previous work
(previously East Coast Low Hazard complete, Investigation of potential for
Tool) providing information on awaiting automated tracking technologies to
significant weather events that have Public release capture and map ECLs
had major impacts on the Eastern of web Research into thresholds for
Seaboard of Australia (ESA) in terms interface, identifying impact producing ECLs
Project Description Progress Details
of rainfall, wind, extreme waves and scheduled by Definition of Eastern Seaboard
storm surge. A cyclone tracking Dec 2011 region
feature will enable identification of Construction of a GIS map of the
ECLs that have impacted on the Eastern Seaboard region
ESA. Obtaining feedback from peak
users through State Emergency
Management Council of NSW
Development of project
interface near completion
Work underway on:
Verification of automated tracking of
Supporting documentation to
2 Projections of future ECL frequency On track, Unsuccessful ARC bid submitted in May
and intensity along the NSW coast early stage 2010. ARC bid resubmitted May 2011.
using global and regional climate An interim pilot project has commenced.
modelling. The project will evaluate model
simulations of major historical ECL
3 Understanding long term natural On track, Commenced July 2010. Project aims
variability of ECLs by using paleo- nearing have been updated and the project
climate information such as oxygen completion team has finished first stages of work. A
isotopes in tree rings and coral cores jpaper on first stage work has been
from the eastern Pacific. submitted to an international journal and
a number of Conference presentations
have arisen. Estimated completion date
4 Assessing regional coastal and On track with ARC Linkage Grant application
estuarine impacts of extreme ECLs Pilot Project. submitted April 2011. First attempt
from the geohistorical record and Full project unsuccessful and revised application to
using this information for coastal delayed by be submitted in April, 2012.
planning for urban settlement, public funding delay
infrastructure and many natural
5 Regional water security impacts of On track, ARC Linkage proposal to be submitted
extreme ECLs on South-Eastern early stage Nov 2011
Seaboard reservoirs. Partner research proposal (ECL & IFD
rainfall intensities) secured funding.
6 Dynamical Downscaling of ECLs. Nil expected No action planned for the reporting
(see details period. Contingent on funding
right) consolidation and developments in
other ESCCI RCM projects
2.0 Background and Objectives
Australia’s south-eastern seaboard
The area of land between the Great Dividing Range and the coast of Victorian Gippsland, NSW and
southern Queensland is home to almost 9 million Australians and billions of dollars of public and
private infrastructure. A variety of high-impact weather events occur in this area and generate
damaging winds, flooding, hail, and heavy seas and swells affecting the state’s environment,
infrastructure and communities. High-impact weather events also play a critical role in water
management with a number of our major water catchments replenished in bursts by extreme rainfall
In particular, the south-eastern seaboard is susceptible to weather events known as East Coast
Lows (ECLs). These events contribute significantly to annual rainfall along the east coast and
ranges, with many of the area’s stored water being derived from the high intensity rainfall of ECL
systems (e.g. Warragamba, July 1998, see Figure 1, whereupon levels almost doubled from just
over 50% to 100% capacity). The water supply implications extend beyond the divide, with large
ECL events bringing significant rainfall to the headwaters of western rivers, particularly in the north
of NSW. ECLs can also be destructive – in June 2007, an East Coast Low caused significant
damage to the coast near Newcastle and led to nine deaths, insurance claims of $1.6 billion, and
the grounding of the M.V. Pasha Bulker. In 2008, a series of storms in southeast Queensland
caused significant flooding and storm damage in Brisbane and Gold Coast. These weather events
also generate conditions that can lead to increased bushfire risk, lightning strike and strong winds.
Sydney : Available Water Storage (Sydney Catchment Authority 2011)
East Coast Low Events
Figure 1: Impact of ECLs on Sydney's Water Security
For these reasons an understanding of high-impact weather events, their variability and how they
will change in the future, is a necessary precursor to determining the impacts of climate change on
natural and human systems and the implementation of effective adaptation strategies. If these
storms increase in intensity, frequency and/or duration in response to human induced climate
change, we can expect significant intensification of impacts on coastal infrastructure and
ecosystems; particularly in light of amplified impacts due to rising sea level. If however these events
decline in frequency, intensity or duration, it may lessen the effects of rising sea level but result in
reduced flows to our water storage infrastructure.
The Australian coast, and in particular the east coast, has greater scientific uncertainty in Global
Climate Model (GCM) projections than the rest of the continent. Large areas like central Australia
are well served by GCMs, but the models have difficulty dealing with small scale weather processes
– such as ECLs – and areas with complex terrain. The east coast of Australia exemplifies this
situation: a narrow coastal plain flanked by the Great Dividing Range, a climatologically significant
feature that is not well factored into current climate models.
Despite the concentration of people and infrastructure in this area it is still one of the least
climatologically studied zones in Australia, and current research is relatively limited, not co-
ordinated nor necessarily focussed on answering key questions for the community. NSW has a
distinct and pressing need for coordinated and focussed attention on coastal and near coastal
climatic processes. This need for information extends beyond the borders of NSW, into northern
Victoria and southern Queensland.
2.1 The Eastern Seaboard Climate Change Initiative
The Eastern Seaboard Climate Change Initiative (ESCCI) is a cooperative research consortium led
by Office of Environment & Heritage, that includes NSW Government Agencies, the Australian
Bureau of Meteorology, the Sydney Institute of Marine Science and a number of major universities
in NSW. ESCCI aims to address information gaps in the nature and impacts of climate change and
climate variability on the Australian east coast, ranges and inshore marine environments (and Lord
Howe Island). ESCCI’s outputs are policy focused.
2.2 ESCCI East Coast Lows Program
The ECL type weather pattern is found only along the Australian east coast and two other places in
the world (off the east coasts of North America and Japan). The behaviour of this weather pattern
and its association with other major climatic drivers such as El Niño and the Southern Annular
Mode are not well understood, but may have a dramatic effect on the way climate change is
experienced on the east coast of Australia and across the tablelands. Changes to rainfall on the
tablelands will also have flow-on effects through to the west of the State, including the upper
Murray-Darling Basin which in turn may influence the water available for irrigated agriculture, urban
water supply and environmental flows within the basin.
The program currently has a number of proposed project-based outputs:
2.2.1 ESCCI- ECL Project 1: East Coast Lows (ECL) hazard tool
The Eastern Seaboard Climate Hazard Tool will link historical ECL events with information on their
impacts (e.g. location and intensity of heavy rainfall, severe winds, extreme waves and storm
surge). This will be achieved by building on, and integrating with, existing datasets and through
consultation with intended peak users of the tool, including emergency managers, water managers,
researchers and the insurance sector. Importantly, the tool will also include information about other
synoptic systems which have resulted in hazardous conditions across the Eastern Seaboard of
Australia (ESA). The Hazard Tool will be accessible publicly, initially through a registered users
website and ultimately through the Bureau of Meteorology’s (BoM) website. It will also include an
automated tracking feature that will capture and map ECL tracks for further analysis. The Hazard
Tool is essential for project 2 as it will:
provide a interactive tool which enables users to understand the proportion of hazardous
conditions which are associated with ECLs compared to other synoptic systems
help to improve understanding of the physical conditions that lead to ECLs and other major
synoptic systems that have impacted heavily on the Eastern Seaboard
inform stakeholders of the seasonal and interannual variability of the ECL phenomenon and
other hazardous weather systems
Assist users in developing a risk profile for hazardous weather conditions across the eastern
The Hazard Tool requires a NSW Government contribution of $150,000 over two years. The BoM
has contributed $200K over two years to this project.
2.2.2 ESCCI- ECL Project 2: Projections of future ECL frequency along the NSW coast
The goal of this project is to determine whether East Coast Lows will change in frequency or
intensity in the future. The project will address this by:
1. Assessing the existing Global Climate Models (GCM) on how well they simulate observed
2. Testing the sensitivity of the model simulations to the choice of physical conditions that are used
as a basis for the model;
3. Determining which physical mechanisms are the most important for the development of ECLs
by performing specific experiments to explore the importance of various external factors such as
the East Australian Current and the large scale atmospheric dynamics; and
4. Performing high-resolution simulations of future climate using a range of plausible emission
scenarios to examine the likely changes in ECL frequency and intensity in the mid and late 21st
The project will:
Provide a clearer picture on what changes can be expected over the next century in the
intensity and frequency of ECLs. This will allow water planners to incorporate this into
projections of available water in dams and storages (Project 5 linkage), and
In combination with the results of projects 3 and 4, enable an estimate of the scale of impact
that rising sea-level in conjunction with storm surge will have on coastal infrastructure and
2.2.3 ESCCI- ECL Project 3: Long term natural variability and probability assessment of
This project will use paleo climate information to examine whether ECLs have been a long term
phenomenon in NSW, and measure their intensity and frequency on a multi-decadal basis over the
last 1000 years. Information will be derived from climate proxies (such as oxygen isotopes in tree
rings) from NSW and across the Tasman in New Zealand, and coral cores from the eastern Pacific
and speleothems (stalactites and stalagmites) in caves in NSW. In particular this project will:
attempt to determine if the frequency of ECLs is related to the dominant regional climate modes
such as the ENSO (El Niño southern oscillation) phenomenon and
provide the basis for risk assessment of extreme ECL events both under natural climate
variability and interpreted from climate shifts associated with climate model projections.
This project will provide input into project 2 by defining and quantifying the likely range of frequency
and intensity of ECLs that we have experienced over the longer term. This will greatly improve the
ability to model the probable changes of ECLs into the future.
2.2.4 ESCCI-ECL Project 4: Coastal System Response and Probabilistic Risk Assessment of
Extreme east Coast Low Sequences
ECLs contribute to erosion of coastal lowlands and abrupt shifts in estuarine ecosystems and their
water quality. This project will:
define regionally distinct impacts for the NSW coastal zone for a range of storm intensities
form the basis for the regional identification of coastal and estuarine vulnerability to extreme
ECL events and
in combination with the results of project 2, allow an estimate of the scale of impact that rising
sea-level in conjunction with storm surge will have on local coastal infrastructure and
The information from this project will be critical for coastal planning for urban settlement, public
infrastructure and many natural ecosystems. For example, results from a pilot study for this work
indicated some of the towns located on geologically recent sand deposits are a great risk from
altered wind and storm patterns associated with variations in ECLs.
2.2.5 ESCCI- ECL Project 5: The Influence of ECL on the Water Security of Coastal NSW
This study aims to better understand the hydrologic importance of ECL and related weather
systems for water supply to major storages. This information will be used to better to understand
how water security will change if future climate change alters the frequency, magnitude and
geographic extent of these weather systems.
To achieve this aim the study will establish the frequency and spatial distribution of low pressure
system within the east coast of Australia, primarily using the Bureau of Meteorology ECL database
(Project 1 linkage). Further information will also be used from related projects (3 & 4) using
paleological records to establish variability over a much longer period.
The study will also help to better represent existing climate variability by checking long term (paleo)
ECL frequency (ESCCI-ECL Project 3) against long term records of dry spells (beyond the
instrumental record of 1895). Understanding how climate variability has impacted weather systems
in the past is important in understanding how climate change may modify this variability in the
At the later stage of the research the following subjects will be better defined: the water security as
a function of ECL, water yield against climate variability with a consideration beyond instrumental
record, the spatial extent of low pressure induced intense rainfall.
The ECL projections will be available from ESCCI-ECL Project 2. This will be used to revise all the
prior analyses in this project for the future climate of 2030 and 2100.
The project will commence in late 2011 and be completed in 2013. In addition to Trust and pending
ARC funding, the project is also co-funded by Dept. Finance & Services and Hunter Water
Corporation. The outputs of the project will be staged to ensure that results are available for
consideration of the review of the 2014 Metropolitan Water Plan and for development of the water
management plan for the Hunter Water region.
2.2.6 ESCCI- ECL Project 6 Dynamical Downscaling of ECLs
This optional project will use the data generated in projects 1, 2 and 3 to develop a higher resolution
regional climate model for the behavior of ECLs over the next century. It has linkages to other (non
Environmental Trust) funded ESCCI projects on Regional Climate Models. Consequently, the
project may be subject to abridging or abandonment if ARC funding is not realized for other ESCCI
ECL projects, and substantial dynamical downscaling research progress is made in alternate
3.0 Research Plans
Research Plan ESCCI-ECL project 1 East Coast Lows Hazard Tool
A. BUILDING A ROBUST CLIMATOLOGICAL DATABASE
B. ADVANCE UNDERSTANDING OF THE BROADSCALE FAVOURABLE ENVIRONMENTS
FOR EAST COAST LOW FORMATION
How will these change in the future?
Could these changes alter the frequency and intensity of future east coast lows on
the eastern Australian coast?
The overall aim of this theme of the East Coast Low (ECL) project proposal is to build an on-going
and robust database of ECLs and their associated impacts. The aim is to establish both
climatologies (in terms of averages and variability), and also to continually detect and monitor any
trends in frequency of occurrence and intensity of these extreme phenomena. It proposes, in this
regard, to build on the work already undertaken by the Bureau of Meteorology NSW Climate
Services Centre (CSC) (Fig. 12).
A. 1 Extend NSWRO/CSC maritime low database:
The NSW CSC has established a database of known systems in the period 1970 to the
present which have formed or intensified over the ocean in an area bounded by 25˚S and 40˚S and
extending from the coast to 160˚E (the database does contain events prior to 1970 but is not
comprehensive prior to this date ). It also has capability to record the impact of events on the coast
in terms of rainfall, wind and waves but has only been populated in relation to rainfall impacts. This
database provides a good starting point. However, it is currently manually intensive with an element
of subjectivity in classification. It is also worth noting that not all systems have an impact signature
over land and therefore this database, as it stands, has not been designed to exactly suit this
research program and hence requires further improvement.
30 Significant Rain
Number of events
5 per. Mov. Avg.
5 per. Mov. Avg.
10 Linear (Significant
5 per. Mov. Avg.
5 (Heavy Rain)
1970 1975 1980 1985 1990 1995 2000 2005
Fig. 12: Annual Frequency of East Coast Low events (based on the existing NSWRO/CSC
The maximum benefit will be gained from the database if the methodology is moved from a
subjective analysis of surface charts to an objective automated or semi-automated analysis which
then could be applied to reanalyses and/or numerical weather prediction analyses. For example,
Pook et al. (2006) have developed an objective cutoff low recognition tool. This algorithm takes
account of the upper air and the surface as well as applying a thickness criterion in order to identify
cut-off lows and could be applied with some confidence to the existing reanalyses back to the late
1950s. Within the course of the project it will be possible to extend existing tools to encompass new
knowledge on broad scale features relevant to the formation of cut-off lows such as the presence of
upper air “blocking” and other large-scale features described in theme 2a.
In addition, while existing databases are based solely on recognised surface synoptic features,
significant rainfall events can be associated with events without a strong surface signature. By
linking this sort of database with impact data (e.g. rainfall), such cases could also be identified (see
proposed methodology in section b, below).
Currently the existing database differentiates several sub-categories based on the synoptic situation
in which the low intensifies or forms. This synoptic typology would need to be reviewed along with
the need to include upper atmospheric and ocean features that may be of even greater significance
in terms of the cyclogenesis of these systems (such as upper jet position, upper lows, temperature
and presence of features such as strong eddies within the East Australian Current (EAC), etc).
However, insight on long-term trends of these systems does seem to emerge from existing
climatologies that use the simpler synoptic classification approach, suggesting that such systems
can still reveal useful knowledge relevant to future climate change (e.g. area of formation - whether
in “the easterlies” (north) or “the westerlies” (south); details on surface pre-conditioners – lows
forming north of a strong high pressure ridge; etc).
A. 2 Generate a rainfall based ECL database
This work would continue the original work by HH97 and also the more recent work by
SW09 to include rainfall data in the NSW CSC database but benefit from advances in climatological
datasets, in particular the 5km Australian Water Availability (AWA) project’s gridded daily rainfall
dataset from 1900 (Jones et al., 2007). New thresholds for spatial coverage and intensity, identified
in consultation with key stakeholders, would be required to identify extreme rainfall events.
Comparisons between the rainfall based ECLs and maritime ECLs database for the reanalyses
period (1958 to now) would help define the right criteria to identify overlapping events. Furthermore,
the identification of ECLs using rainfall criteria has the potential to be extended back to 1900 which
will lead to a larger database and help with the climatological analyses (inter-annual, decadal and
B. Advance understanding on cyclogenesis and favourable broad scale circulation:
As noted earlier, there is a need for a more systematic understanding of the larger-scale
dynamic or environmental ingredients conducive to the development of ECLs, and hence it is critical
to advance that understanding. This is a critical development and a mandatory step for a better
understanding of the potential impact of future climate change on the larger-scale environment and
dynamical ingredients that drive or enable the development of ECLs
Fig. 13: Regional field of 400 hPa (approximately 6km) wind and isentropic potential vorticity
overlaid on contrast-enhanced satellite imagery in the “water-vapour channel”, valid for the 8th of
June 2007. The dark areas correspond to dry air in the upper troposphere.
B. 1 Understanding the ECL cyclogenesis:
Careful analysis of the cyclogenesis of some spectacular cases of ECLs reveals some
interesting features in term of broad-scale circulations (G. Mills, communication to the ECLs
workshop, 2008). The sequence leading to the development of such ECLs is:
An upper-tropospheric split-jet, or blocking pattern, upstream of eastern Australia, with a
positively tilted trough or cut-off low over eastern Australia
Amplification of the upstream trough over the Indian Ocean, subsequent amplification of the
immediate upstream ridge south of Australia
The next stage of this energy-dispersion process is the development of a southerly jet streak on
the western side of the positively tilted trough over eastern Australia
As this southerly jet streak propagates towards the apex (lower latitudes) of the trough, the
trough/cut-off low deepens and begins to tilt towards the northeast and move towards the coast
The consequence of this evolution is a focussing of Isentropic Potential Vorticity (IPV) advection
on the northeast side of the cut-off low, which forces pressure falls at the surface
If low-level ingredients are suitable, explosive development of an ECL occurs.
This analysis suggests the possibility of identifying large-scale “risk factors” necessary for the
formation of ECLs. To ensure these could become a meaningful diagnostic, a systematic analysis is
required on a larger set of cases (therefore linking with the effort to develop a more comprehensive
database for maritime lows/ECLs described in theme 1) to confirm the role of this mechanism
across all the known cases.
In particular, the direction of tilt of the upper trough may not necessarily be consistent for all ECLs.
Analyses of cut-off lows in southeastern Australia (Pook et al., 2006) reveal intense systems
forming in anticyclonic thermal involutions and cyclonic thermal involutions with apparent changes
in the orientation of the upper trough over short periods. Just where and when the block amplifies
seems to be an important factor and therefore, the role of extending this analysis to the
climatological record is to verify the generality of the mechanism outlined above to other cases.
In order to do so, this analysis then must be extended to the complete analysis history (up to 50
years) to ensure the robustness of the diagnostic. This work can be done using existing re-analyses
(NCEP/NCAR and ERA40 as well higher resolution interim ECMWF reanalyses once they became
It is recognised that the translation from a conceptual diagnostic to a “fingerprint identification”
algorithm is challenging. Often these diagnostics contain various thresholds that must be crossed to
trigger the recognition of a risk of an event (such as an ECL). These thresholds are often a function
of grid spacing and, therefore, are a practical constraint for future application to GCM outputs.
Performing this analysis on several reanalyses will help to refine the identification criteria and also
identify limitations of modelled gridded information for the diagnosis of ECLs. Applying the
identification criteria to different reanalysis products and comparing the results may also yield
insights into the role of model physics and the importance of horizontal resolution on ECL formation.
It might be possible to include probabilistic information regarding these important thresholds
dependent on the model physics (different models are used by the centres producing reanalyses)
and the role of the horizontal resolution. It may also lead to the ability to prioritise different criteria
used for ECL identification.
Complementary to identification of the large-scale upper-air precursor to the ECL’s future formation
downstream, a careful analysis of the surface ingredients necessary for the intensification to occur
are essential and could lead to appropriate criteria that complement the subjectively differentiated
sub-categories of ECLs in theme 1.
B. 2 Application to climate models:
Following on the previous development, the ECL risk diagnostic will be applied to climate
simulations of the current climate. This first stage will help evaluate the applicability of the
diagnostic to climate models. Outputs from climate models are comparable to reanalyses without
the constraint of observed data and with equal or coarser resolution. This evaluation will also be
used to evaluate existing GCMs with respect to a criterion highly relevant to coastal eastern
In a second stage, the diagnostic will be applied to simulation of the 21st century climate to evaluate
the impact of climate change on the risk of formations of ECLs. In conjunction with the model
evaluation mentioned earlier this is likely to lead to a possible narrowing of the less uncertain
rainfall projections for coastal eastern Australia based on the models’ ability to produce realistic
climatology – and its evolution due to climate change- of the risk of formation of ECLs. Such an
advance would then provide more meaningful projections for water resources and for the impact of
extreme weather events. A limitation of this methodology, however, is that it is unlikely to provide
quantitative information regarding the rainfall amount produce by ECLs and how that amount might
change under global warming, or whether the spatial distribution of ECL formation (closer or further
from the coast, further north or south) will change. This quantitative information will require
numerical modelling at high resolution of cases now and in the future climate (as proposed in theme
In addition to the work done specifically on large-scale conditions favourable to ECL cyclogenesis,
climate model simulations will be also used to evaluate large-scale modes of variability which have
been linked to ECL climatology (as part of theme 1 research). This analysis will help evaluate
climate model ability to reproduce the current climate and hence provide a mechanism to rank
existing models and reduce uncertainties of future projections. It is anticipated that this aspect of
the program which covers a much broader ground than ECLs will not require an important
investment as it will benefit from on-going research in existing climate programs such as the
Australian Climate Change Science Program (ACCSP) supported by the Department of Climate
Change (DCC) and the South-Eastern Australian Climate Initiative (SEACI).
3. Deliverables for 10/11 financial year
Sub project 1A
A. Review existing databases and mine all relevant and available ECL data. All existing
ECL information is to be located and consolidated in a central repository at the NSW CSC. This will
include all relevant published scientific papers and technical reports.
B. Investigate the potential of automated tracking technologies to adequately capture
and map ECL’s is to be investigated. Work already undertaken by Melbourne University and
David Jones (BOM) on automatic tracking software is likely to be very valuable to this project and is
currently being tested for its applicability.
C. Develop thresholds for identifying impact producing ECLs. Through discussions with
various stakeholders, such as the NSW State Emergency Services Council (SEMC), OEH and the
Climate and Water divisions of BoM, thresholds for significant coastal rainfall, wind, wave and storm
surge events are to be analysed. This research will be utilised to identify possible significant
synoptic events by impact type rather than by solely utilising surface synoptic patterns. It will also
form the basis for user guidance in selecting thresholds relevant to their line of work. Stakeholder
engagement early in the project development will inform the development of both the database and
the interface created for data interrogation. Work on this deliverable will be conducted jointly with
theme 2 of the ECL research program as it investigates the broad scale environments suitable for
the formation of high impact ECLs and other synoptic events.
D. Commence digitisation of remaining coastal observations. Many historical
meteorological observations from the east coast of Australia exist only in paper form. To support
ESCCI research, including the ECL project, BOM are undertaking a digitisation project using the
resources of the National Climate Centre. Historical observations from the 1800’s and perhaps as
early as the first European settlement will be reviewed and if suitable entered into the Australian
Data Archive for Meteorology (ADAM). NSW CSC will be coordinating the digitisation project and
prioritising records for processing.
E. Develop a detailed project proposal for the activities of 2010/11 and 2011/12 financial
years. The commencement of the construction and population of the comprehensive ECL
database is due to begin early in the 2010/11 financial year and be completed by early in 2011/12
with subsequent interrogation and analysis through to the end of 2011/12. The proposal will detail
the costings associated with procuring a professional database designer and the labour costs
required for populating the database with event information.
F. Establish the Hazard Tool interface. The project’s IT developer will establish the Climate
Hazard Tool interface by developing a website and embedded algorithm to interrogate the BoM’s
data archive according to user selected inputs, such as dates/area/phenomena/threshold. He will
also integrate the automated cyclone tracking program to capture and map ECLs occurring in the
ESA region using high resolution MSLP reanalysis data.
G. Develop supporting documentation and user guidance material. This will be available
through links from the Hazard Tool interface for background information and project methodology
for interested users. This will also acknowledge contributions from other agencies, eg. Manly
Hydraulics. The guidance material will assist users in choosing phenomena thresholds applicable to
their area of interest and/or research.
Sub project 1B
A. Identify case study events with significant impacts on the NSW Coast. The broad
scale circulation patterns preceding and during these events will be analysed and form the basis of
the research in Theme 1B. This links closely with deliverable C in Theme 1A.
B. Commence identification of large-scale “risk factors” necessary for the formation of
high impact ECLs. To ensure these could become a meaningful diagnostic, a systematic analysis
is required on a larger set of cases (therefore linking with the effort to develop a more
comprehensive database for maritime lows/ECLs described in theme 1A) to confirm the role of this
mechanism across all the known cases. This work can be done using existing re-analyses
(NCEP/NCAR and ERA40 as well higher resolution interim ECMWF and MERRA reanalyses once
they became available). Identification is required of both the large-scale upper-air precursors and
also the surface ingredients necessary for ECL formation and intensification to occur. This work
could lead to appropriate criteria that complement the subjectively differentiated sub-categories of
ECLs in theme 1A.
4. Project Personnel
Overall management of the broader ECL Research Program and its three themes is the
responsibility of Dr Bertrand Timbal, Centre of Australian Weather and Climate Research
Sub project 1A
A small steering committee for theme 1A of the ECL research program will be comprised of
Bertrand Timbal and the Manager of NSW Climate Services Centre (position to be filled in March
2011). The project officers responsible for the deliverables listed above are Felicity Gamble, Agata
Imielska and Acacia Pepler of the NSW CSC and Martin Schweitzer of Data Services, all from the
Bureau of Meteorology.
Sub project 1B
A small steering committee for theme 1B of the ECL research program will be comprised of
Bertrand Timbal, Graham Mills of CAWCR and Perry Wiles, National Climate Centre (BOM). The
project officer responsible for the deliverables listed above is currently Andrew Dowdy.
Hopkins, L.C. and G.J. Holland, 1997: Australian heavy-rain days and associated East Coast
Cyclones: 1958:92, J. of Clim., 10, 621-635
Jones, D., W. Wang and R. Fawcett, 2007: Climate Data for the Australian Water Availability
Project, Final milestone report, Bureau of Meteorology
Pook, M, P. McIntosh and G. Meyers, 2006: The synoptic decomposition of cool season rainfall in
the south-eastern Australian cropping region, Journal of Applied Meteorology, 45(8), 1156–
Speer, M., P. Wiles and A. Pepler, 2009: Low pressure systems off New South Wales coast and
associated hazardous weather: establishment of a database, Aus. Met. Mag. (accepted)
Shand, T., I. Goodwin, M. Mole, J. Carley, S. Browning, I. Coghlan, M.Harley and W.Peirson, 2011:
NSW Coastal Inundation Hazard Study: Coastal Storm and Extreme Waves, WRL Technical
Modra, B., 2010: NSW Ocean Water Levels, Draft Report MHL 1881
7. Contact details
Position to be filled in March 2011
Manager NSW Climate Services Centre
Bureau of Meteorology
Ph: 02 9296 1525
Fax: 02 9296 1567
NSW Climate Services Centre
Bureau of Meteorology
Ph: 02 9296 1610
Fax: 02 9296 1567
Research Plan ESCCI-ECL Project 2 Projections of future ECL frequency along the NSW
Will East Coast Lows (ECLs) change in frequency or intensity in the future?
A proposed Linkage proposal on East Coast Lows (ECLs) between UNSW, NSW OEH and BoM
The New South Wales Coast is subject to heavy rain, strong winds and large waves resulting from
low pressure systems adjacent to the Tasman Sea that develop from a variety of synoptic and
mesoscale systems. These systems, referred to as “East Coast Lows”, cause a significant amount
of damage along the east coast of NSW each year. One outstanding issue is if or how these events
might change in the future under climate change. This Linkage proposal aims to address this by
answering the following question:-
Will East Coast Lows (ECLs) change in frequency or intensity in the future?
The answer to this question will be achieved by meeting the following objectives:-
Objective 1. Evaluate Global Climate Model (GCM) ability to simulate ECLs and examine
projected future change in ECLs
In order to do this we will:
i) Develop a definition for ECLs valid at GCM resolutions
ECL systems will be defined in a manner consistent with the other working groups and CAWCR.
Since this definition will be used to identify ECLs in GCM output it must be valid at GCM spatial
scales and at the daily time scale, and provide a measure of the intensity of the ECL. Thus, while
ECLs are identified at the higher resolution in an operational forecast, the objective methodology
developed here will identify ECLs at the resolution of GCMs (~1° to 3° grid). This ECL identification
methodology will be tested on reanalysis datasets that are essentially GCM models that have been
constrained to the observations, allowing a direct comparison with the ECL database (being
produced in Theme 1). A number of reanalysis products are available that span the spatial
resolution of GCMs providing a rigorous test of the methodology.
ii) Identify the frequency and intensity of ECLs in 20th century GCM simulations
Using the Coupled Model Intercomparison Project phase 3 (CMIP3) archive we will compare
modelled and observed statistics of ECL frequency and intensity. This will allow a ranking of the
GCMs based on their ability to capture 20th century ECLs and provide a basis for weighting future
climate simulations in preference to those models that perform well.
iii) Identify ECLs in future projections
Here we will assess whether the frequency or intensity of ECLs is predicted to change in the future
by comparing future and present day ECL statistics and by understanding the limitations of this
technique identified previously.
iv) Identify ECLs in the next generation of global climate models
In the last year of the project, model runs performed through the Coupled Model Intercomparison
Project phase 5 (CMIP5) in preparation for the IPCC Fifth Assessment Report (AR5) in 2013 will
make it possible to use the latest generation of GCM simulations to implement the techniques
described above and reassess the projected future changes in ECLs.
Objective 2. Perform high resolution regional climate modelling simulations of ECLs
Given the relatively small spatial scale and longevity of many ECL events it is likely that some of
these can not be identified at GCM resolution. This will be tested by performing dynamical
downscaling of reanalysis output using the Weather Research and Forecasting (WRF) regional
climate model. Simulations of the late 20th century will be performed using spatial resolutions of
50km and 10km and an output time step of 3 hours.
Using the objective methodology developed in objective 1, ECLs will be identified in the WRF
simulations and evaluated against the ECL database (developed in theme 1). This will allow the
methodology to be refined at these higher spatial scales.
Several important issues concerning which physical processes are most important in the
development of ECLs need addressing in order to perform the best possible downscaling. The two
experiments outlined below will directly address two of the main candidates that may strongly
influence the downscaling.
i) Importance of large scale dynamics on the Regional Climate Model (RCM)
RCM simulations are driven at the lateral boundaries by GCM (or reanalysis) fields but inside the
RCM domain atmospheric states evolve freely. This means that large scale features within the
domain may evolve at a different rate or to a different intensity to that produced by the driving global
model. Using spectral nudging, large scale features in the upper atmosphere are kept in-sync with
the global model. Here an experiment will be performed using spectral nudging to determine
whether this effect is important in the production of ECLs.
ii) The role of the East Australian Current (EAC) in the production and intensification
At present the role of the EAC in the production and intensification of ECLs remains largely
unquantified. Using RCM simulations the importance of the EAC will be tested. By comparing the
results of RCM simulations using low resolution Sea Surface Temperatures (SSTs), such as those
in GCMs which do not resolve the EAC, and high resolution SSTs derived from satellite
observations, the impact of the EAC on the development of ECLs will be determined.
ROLE OF PERSONNEL
This project offers emerging young scientists the opportunity to be at the forefront of both
scientifically challenging and policy relevant research. They will be guided by the expertise of
established researchers and policy makers to ensure research excellence and that the project
outcomes will be delivered on time.
Participant roles are as follows:
Research Scientist 1 will perform the reanalyses based regional climate simulations and in-depth
evaluation against observations. They will also subsequently perform the sensitivity and hypothesis
tests to establish a quantitative understanding of the mechanisms involved in the initiation and
development of ECLs.
Research Scientist 2 will be responsible for performing the GCM driven regional climate
simulations for both present day and future climate scenarios, analysing the changes that occur and
the mechanisms behind these changes.
CI Evans will be responsible for the overall management of the project, including liaising with
project partners. He will lead the regional climate modelling and be responsible for teaching the
research scientists to successfully use these tools. He has extensive experience using RCMs to
produce climate change projections, as well as performing sensitivity analysis and hypothesis
CI Alexander will provide the two RSs with training on the appropriate statistical techniques
necessary to analyse extreme events such as ECLs. She will provide outstanding international links
for the RSs and this research through her leadership roles on several major extremes initiatives
including guidance on how to appropriately compare modelled and observed extremes.
CI Sherwood as one of the world leaders in atmospheric dynamics will provide the necessary
expertise to advise the RSs on the structure and development of ECLs. His extensive knowledge of
both atmospheric observations and models will provide the RSs with expert guidance throughout
each stage of the project.
PI Rakich was instrumental in establishing the Eastern Seaboard Climate Change Initiative and will
ensure that project outcomes align with but do not overlap the ESCCI project objectives. His
cosupervision of the RSs will guide the automatic ECL detection objective and will also ensure that
the project aim to improve ECL forecasting will be met and that the project outcomes align with
BoMs strategic objectives.
OEH will contribute to the overall direction of the project to ensure that stakeholder requirements
are met through chairing the steering committee. They will provide the necessary link to the
Australian Climate Change Science Framework to ensure that outcomes meet national objectives.
They will also provide the necessary communication to state and federal government agencies as
Research Plan For ESCCI-ECL Project 3 Long term natural variability and probability
assessment of ECLs
Topic: extending the extreme east coast low climatology over the past millennium
The historical records over the past century show that the magnitude and frequency of East Coast
Lows (ECL) is linked to decadal-scale variability in the climate system. This project will produce a
climate pattern time-series using proxy climate data from the Australasian, New Zealand and
Antarctic regions. Decadal-scale modes of climate variability that have occurred over the past 1000
years will be determined as the basis for an investigation of the magnitude-and frequency of ECL's
in the Trans-Tasman Sea region. The study will also investigate the associated anomalies in air
pressure, south-eastern Australian rainfall and Tasman Sea wave climate. The project will provide
the basis for making risk assessments of extreme ECL events for a range of recurrence intervals,
both under natural climate variability, and projected climate from existing coupled climate model
BACKGROUND AND AIMS
East Coast Cyclones also known as East Coast Lows (ECL) are complex weather systems that
form off the east coast of Australia and/or travel parallel to the coast of Australia from south-east
Queensland to Victoria. They can cause significant storm damage to both the natural system and
human infrastructure. There are a few types of coastal ECL, with the main types being: a primary
type that develops in an easterly low pressure trough (usually cradled by a slow moving anticyclone
to the south-west of New Zealand), typically off the northern NSW and SE Queensland coast; and a
secondary type known as a Southern Secondary Low (SSL) that develops in the wake of a cold
front, forming a cut-off low over the western Tasman Sea, typically off the NSW central coast; and
thirdly Continental Lows and Inland Trough Lows that intensify off the central to south coast region.
These systems develop from the interaction of the surface trough and an upper atmosphere low
pressure system, cut-off from the westerly air stream. In all cases, a strong sea-surface
temperature gradient in the Tasman Sea is essential for the development of these weather
ECL’s can cause contrasting coastal behaviour between southern, central NSW and SE Qld. Our
previous research has demonstrated that ECL’s are associated with secular shifts in the major
hemispheric modes of extratropical climate variability: (i) the Pacific South American mode; and, (ii)
the Southern Annular Mode. The teleconnection relationship between these extreme weather
systems and the El Nino-Southern Oscillation (ENSO) is time varying. ECLs may be associated
with El Nino conditions and SSL’s with La Nina conditions depending upon the coupling of tropical
and extratropical circulation in the mid latitudes. However, their magnitude appears to be greatest
when they occur in transition months between ENSO states, or during abrupt shifts in climate.
The project aims are:
1. Refine the climatological diagnostics of ECLs from the available instrumental climate
reanalysis data, ECL synoptic meteorology, and sea-surface temperature data archives
2. Expand existing databases of ECLs and the magnitude-frequency relationship;
3. Reconstruct a proxy time series of Trans-Tasman Sea region pressure and wind fields, and
ECL frequency and over the past ~1,000 years, at quasi decadal resolution and magnitude
at quasi annual resolution using multiple paleoclimate records,
4. Conduct a probabilistic risk assessment of ECL magnitude-frequency due to natural climate
Task 1. The methodology that will be used to address Aim 1 and 2 is based on: (i) Synoptic Typing
(ST) of the ECL types using Self Organised Mapping (SOM) of the NCEP-NCAR Reanalysis (NNR)
daily climate composite data (1948-2010) surface and mid-tropospheric pressure and winds, sea-
surface temperature; (ii) climate data stratification according to the phase of the major hemispheric
climate modes: PSA, SAM and ENSO; and, (iii) reclassification of ECL types in the existing
seasonal maritime low databases, held by the BoM, Macquarie University/Climate Futures/Risk
Frontiers and NIWA.
Task 2. The methodology that will be used to address Aim 3 is based on synthesis of proxy
atmospheric circulation time series reconstructed from: (i) Antarctic ice core, major ion chemistry;
(ii) New Zealand tree rings and cave speleothems; at annual/seasonal resolution, and (iii) east
coast Australian paleological storm erosion shoreline sequences archived in coastal strandplains. In
addition, Australian and south-west Pacific proxy sea-surface temperature time series reconstructed
from coral geochemistry will be used to develop the Trans Tasman region sea-surface temperature
history. These proxy atmospheric circulation and sea-surface temperature time series will be
analysed using statistical methods recently determined by our research team to first develop a
quasi-decadal time series of the major climate modes, their cyclicity, dominance, and phase shifts.
These records will then be assimilated and converted to ECL Synoptic Type magnitude-frequency
time series using the climate diagnostics and self-organised maps (SOM) produced in Task 1.
Task 3. The methodology that will be used to address Aim 4 is based on statistical methods using;
(i) random-phase resampling of the ECL Synoptic Type time series conducted multiple times; (ii)
Monte-Carlo simulation of ECL Synoptic Type occurrence as a function of the major climate modes;
and, (iii) development of probability density functions for both methods, that will define the
probability risk assessment of ECL occurrence and magnitude.
The principal outputs will be: (i) an improved classification of ECL climatology and a new ECL
database to be contributed to ESCCI ECL Theme 1 project on the ECL Hazard Tool; (ii) unique
~1,000 year time series of ECL synoptic type magnitude-frequency, and relationship to the major
climate modes (PSA, SAM and ENSO) that will contribute to the ESCCI ECL Theme 1 project on
the dynamical meteorological forecasting of ECLs and the Theme 2 project on Future ECL
projections using regional-scale climate models, and (iii) a probability risk assessment of ECL
events that will contribute to Theme 1 ECL Hazard Tools.
The chief investigator will be A/Prof Ian Goodwin, Director of Climate Futures at Macquarie
University. His responsibilities will be to supervise the project and a Postgraduate Student at
Macquarie (Mr Stuart Browning), and a Research Scientist (TBA), together with Dr Drew Lorrey
from the New Zealand National Institute of Water and Atmosphere (NIWA) will undertake the
climate analysis and development of the proxy ECL time series and extreme maritime storms in the
sub-tropics and mid-latitudes.
Both Goodwin and Lorrey will interpret the decadal Trans-Tasman region climate history from their
previously developed proxy climate data. Goodwin will work with Dr Matt Mason from Risk
Frontiers (Macquarie University) to undertake the statistical methods to develop the probability risk
assessment. The project personnel will work closely with a climatologist from the Bureau of
Meteorology (BoM, Sydney Office) such that the project is synchronised with the ECL Theme 1
project on the dynamical meteorology of ECLs, being conducted by the BoM.
Research Plan For ESCCI-ECL Project 4 Coastal System Response and Probabilistic Risk
Assessment of Extreme East Coast Low Sequences
Shoreline erosion, sand dune transgression, breakout and migration of estuarine inlets, ocean and
river flood inundation of coastal lowlands, abrupt shifts in estuarine water properties and
ecosystems, and sediment transport patterns are impacts of East Coast Low's. Historical
observations of these impacts extend over a short time period. This project will develop a longer
temporal perspective of the spatial impacts of extreme storm events along the NSW coast for the
range of probable storms in a 1,000 to 1,500 year period. This will describe the natural variability of
storm impacts on the NSW coast and will contribute to the regional identification of coastal and
estuarine vulnerability to extreme ECL events with a range of recurrence intervals. The Probability
Density Functions (PDFs) of storm intensity, magnitude and clustering will provide a benchmark for
the statistically generated PDFs and exceedance curves currently used in engineering design and
hazard management. The project will provide Evidence-based research on the resilience and
adaptive capacity of natural coastal systems to climate change.
The chief investigator will be A/Prof Ian Goodwin, Director of Climate Futures at Macquarie. His
responsibilities will be to supervise the project and a Postgraduate Student at Macquarie, undertake
the geohistorical research and development of the probability risk assessment, with Dr Matt Mason
from Risk Frontiers. The project personnel will also include: Dr Tim Cohen, flood paleohydrologist
and geomorphologist, and Mr David Hanslow, coastal process specialist, and potentially a scientist
with skills in estuarine sedimentary and ecosystem processes (saltmarsh/mangrove environments),
both from the OEH Water and Coastal Science Section.
Aims And Objectives:
The main aim is to establish a geohistorical record of the magnitude and extent of coastal, estuarine
and lower floodplain impacts from each of the major synoptic extreme storm types affecting the
NSW coastline: East Coast Lows and Southern Secondary Lows. This will build on observational
data on storm beach and dune erosion, storm surge runup and inundation, and estuarine inlet
ocean breakouts, storm wave climate, and coastal lowlands flooding, collected over the past few
decades, and build on current studies such as: (i) OEH projects on Extreme Storms and Inundation
– Extreme wave climate and storm surges; (ii) coastal hazard assessment by Risk Frontiers; (iii)
storm erosion, coastal inundation and estuarine inlet migration hazard assessment in NSW
coastline hazard studies; and, (iv) storm surge and riverine flood modelling. Existing research by
the PI indicates that high-frequency, high-magnitude extreme storm periods occurred during: 800-
1000 AD; and the early 1700’s; the early 1800’s, and between 1950 and 1976. Data and insights
from the partner ESCCI project on the long-term (1000 years) natural variability and probability
assessment of east coast lows and their climatology will also inform this project.
1. To determine the impact of a range of storm events on coastal, estuarine and floodplain
morphology, including: storm beach/dune erosion, coastline realignment and curvature,
nearshore and dune sediment budgets, estuarine and lagoon entrance behaviour (breakout,
closure and migration), storm surge inundation extent and elevated water level in estuarine
environments, and flood history on coastal lowlands.
2. To determine independent probability density distributions for: (i) storm erosion demand and
(ii) storm surge inundation; together with a combined assessment of storm surge and river
3. To interpret a probabilistic assessment of storm magnitude/frequency recurrence and define
the ‘ultimate storm impacts’ for northern, central and southern NSW coasts.
4. To determine the recovery rates of the open coast, estuaries and adjacent floodplain to the
range of extreme storm events, and to identify the threshold or tipping points for abrupt
physical changes, such as inlet/entrance switching or coastline realignment, essential to the
understanding of coastal ecosystem dynamics.
The project methodology is an innovative combination of state-of-the-art geoscience, coastal
modelling and risk analysis. However, we recognize that for the project to be achievable in a three-
year timeframe, it will be essential to work on targeted sites that are representative of the different
latitudinal coastal zone segments in NSW, and that the results can be applied to ‘climate-change
hotspots’. We define the latter as those locations previously defined (e.g. in the OEH Climate
Change Biophysical Scan process, or by the Commonwealth Department of Climate Change (DCC)
‘first pass’ coastal risk and vulnerability assessment (DCC, 2009), and that comprise locations
where significant settlement, infrastructure, and/or biodiversity and resources co-exist. We also
recognize from our existing research that East Coast Lows impact the coastal zone from SE
Queensland to the Sydney Region, and Southern Secondary Lows impact the Hunter Region to
South Gippsland in Victoria.
Field study sites will be drawn from the existing archive of coastal geoscience data held by The
NSW Department of Mineral Resources, Macquarie, Sydney, UNSW and Wollongong Universities,
and the Geoscience Australia OzEstuaries database. Suitable field locations are: One site chosen
from, Byron Bay and Lennox Head coast, Iluka and Clarence coast, Nambucca, Bellinger and
Southern Coffs Harbour regional coast; one chosen from Port Stephens coast, Lake Macquarie or
Tuggerah coast; a Central Coast or Sydney Region embayment, e.g. Avoca/McMasters, or
Narrabeen/Collaroy; one chosen from the Shoalhaven coast, or Moruya Coast; and one chosen
from the Tathra coast, Wonboyn coast or Mallacoota coast.
Modern records of coastal shoreline and dune movement survey data, shoreface bathymetric data,
beach/dune photogrammetric data, and estuarine inlet configuration and dredging data, and
waverider buoy recorded wave climate data comprise a suite of time slice data on recent (50 years)
coastal behaviour, and storm wave climate. These data will be extended over the past 1,000 years
using geoscientific methods including: (a) Ground Penetrating Radar subsurface surveys of
foredunes and relict foredunes to identify paleoscarps depicting major erosion events, and
subsequent sediment accretion packages, storm deposits, and in conjunction with aerial
photographs, paleoshoreline location, curvature and alignment evolution, and paleo-estuarine inlet
evolution; (b) sediment coring of dunes and storm deposits from dunes and estuarine or lagoon
floors to provide samples for the chronological control of shoreline evolution and storm event
occurrence using Optical Stimulated Luminescence (OSL) methods; (c) shoreline planform
geometric change in association with storm-wave climate will be determined using hindcast wave
refraction modelling together with the spatially mapped sequence of storm shorelines; (d) during
sediment coring from lagoon floors, and estuarine inter-tidal and supra-tidal flats to identify marine
inundation events; and (e) sediment coring from estuarine bayhead deltas to identify riverine
Task 2 - Geospatial Analysis of Coastal and Estuarine Morphological Change
The geomorphic data will be used to constrain the shoreline, inlet and dune configuration at multi-
decadal resolution. Time-slice impact maps will be prepared in a Geographic Information System
(GIS). Whilst, we will be resolving the cumulative impacts of frequent extreme storm event periods,
rather than individual storm events, our prior research has shown that there is a high probability that
the geomorphic/sedimentary signatures of the ultimate storm event is preserved in the foredune
sequence on the open coast and within the lagoon floor sediments. Paleostorm wave climate data
will be hindcast using Danish Hydraulics Institute (DHI) spectral wave modelling software, and this
will allow the extension of our present understanding of storm wave climate and associated
Task 3 – Probabilistic Assessment and Risk Analysis
A magnitude-frequency assessment together with probabilistic assessment methods will be applied
to the identified coastal and estuarine impacts. Probability of Exceedance data will be determined,
together with Probability Density Functions (PDF’s). A Monte-Carlo simulation will be made of the
storm erosion demand and storm inundation occurrence as a function of the major ECL synoptic
1. A comprehensive storm event history and detailed record of coastal and estuarine impacts
compiled as Geospatial Data and as PDF’s. The latter will be compiled for application by
OEH and the Bureau of Meteorology (BoM) to develop the ECL Hazard tool to cover a
maximum probable event with a return period up to 1,000 years;
2. A scientific understanding on the thresholds in coastline, inlet and estuarine morphological
response to extreme storms that will precipitate abrupt changes to biodiversity, natural
resources, settlements and infrastructure on open coast and estuarine systems.
Research Plan for ESCCI- ECL Project 5 : The Influence of ECL on the Water Security of
East Coast Lows (ECLs) are intense low-pressure systems which occur off the east coast of
Australia. They often intensify rapidly overnight, making them one of the more dangerous weather
systems to affect the NSW coast. ECLs can generate gale force winds along the coast and adjacent
waters, resulting in heavy swells and rough seas, as well as heavy rainfall often resulting in major
On the positive side, ECLs and their associated rainfall have also been identified as important for
generating significant inflows into major water storages along coastal NSW (Wiles et al, 2009).
Each year there are about ten significant maritime lows. Generally, once a year, these troughs
develop into a major event and these major events are critical to water security in the densely
populated eastern seaboard.
Even though the importance of ECLs is acknowledged there is minimal understanding and
unresolved questions relating to:
the relationship between ECLs and the magnitude, frequency, duration and location of
extreme historical storm events (i.e. heavy rainfall, high seas, and/or strong winds);
how ECLs form (i.e. what makes a regular maritime low turn into a major ECL event) and the
characteristics and relative importance of different types of ECLs (i.e. ECL bombs versus
historical ECL magnitude, frequency, location, duration, path and geographical extent and
how this and the related impacts have varied (and/or trended) over time;
historical ECL magnitude, frequency, location, duration, path and geographical extent and
how this and the related impacts are linked to large-scale drivers of hydroclimatic variability
such as ENSO, IPO, IOD, SAM etc;
historical variability and trends in ECL behaviour and how has impacted historical water
availability, dry spells, and breaking of dry spells along coastal NSW;
the likelihood and characteristics of changes to ECL magnitude, frequency, location, path
and geographical extent under anthropogenic climate change and resulting implications for
water security along coastal NSW.
As such this document outlines the proposed scope of an ARC Linkage application to be submitted
in the November 2011 funding round. The research will be conducted as part of the Eastern
Seaboard Climate Change Initiative (ESCCI) which is a cooperative research consortium led by
NSW Office of Environment and Heritage (OEH) and includes NSW Government Agencies, the
Australian Bureau of Meteorology, the Sydney Institute of Marine Studies and a number of major
NSW based universities. Other partners involved in this study include Hunter Water Corporation
and the Sydney Catchment Authority. This project complements the work being done within SEACI.
The overall objective of the project will be to investigate the importance of ECLs for the water
security of coastal NSW. The project is broken up into three interconnected sub-projects:
1. East Coast Lows (ECLs): formation, impacts, historical variability and future projections
2. What is the hydrologic validity of downscaled climate information emerging from NARCliM
(Jason Evans and co at UNSW)?
3. How reliable are water supply systems on the Eastern Seaboard? How sensitive is this
reliability to changes in East Coast Low (ECL) behaviour?
Sub-project 1: East Coast Lows (ECLs): formation, impacts, historical variability and future
Uni of Newc Staffing: 1 x PhD supervised by AK, DVK (50% each)
Work is currently underway investigating trends and variability of rainfall along the east coast of
NSW and how the distribution of that rainfall shifts over time, with a particular focus on extreme
rainfall events and how they relate to ECLs (Agata’s PhD).
Preliminary investigations into ECL trends and variability and the correlation between ECLs and
various large-scale climate modes (e.g. ENSO, STR etc) have also been conducted by Bertrand
Timbal and Andrew Dowdy as part of SEACI.
The BoM is in the process of preparing a detailed database of coastal lows pressure systems,
including ECL, from approximately 1950 to present. This involves the characterisation of different
types of ECLs and an assessment of their different impacts.
It is intended that sub-project 1 extends this previous and ongoing work by focusing on:
A literature review to clarify what is known and not known regarding how ECLs form and
how the different types of ECL are defined;
Complementing the ongoing work of Agata by concentrating on variability and trends of east
coast dry spells (and the breaking of those dry spells) and how these relate to ECLs. Note
that, in addition to rainfall, dry spells will be assessed with respect to hydrological indicators
(e.g. streamflow and reservoir storage levels);
Continuing the investigations into historical ECL magnitude, frequency, location, path and
geographical extent and how this and the related impacts are linked to large-scale drivers of
hydroclimatic variability such as ENSO, IPO, IOD, SAM etc. Note this will extend previous
work as the analysis will employ methods designed (and previously demonstrated) to cope
with the non-linear, non-stationary and interactive nature of the phenomena under
investigation as opposed to the single drive, linear correlation approach that has been
employed in existing ECL studies. This analysis will utilise several data sources such as
observed station data, reanalysis data, and paleo information (from Ian Goodwin et al
(ESCCI project 3 & 4) ??) and will focus on the various different types of ECL. This is
important as there is currently confusion and inconsistency in the literature and research
community as to what type of ECL has been assessed in the various studies. Other specific
questions considered will include:
o how have ECL tracks differed in the past?
o Does an absence of one type of ECL make another type more likely?
o can the relationships between ECL behaviour and large-scale climate modes be
used to forecast periods of elevated or decreased likelihood of ECL development?
Analysis of NARCliM GCM/RCM outputs (and other CMIP5 GCM/RCM outputs) to
determine how well (if at all) the climate models simulate (a) the historical variability in ECL
magnitude, frequency, location, duration, path and geographical extent and impacts and (b)
the historical relationships between ECL behaviour and large-scale climate modes (in
collaboration with Jason Evans at UNSW)?
Investigating how ECL behaviour might vary in the future (e.g. 20, 50, 100 years) under
anthropogenic climate change and natural variability? What are the implications of this for
water security? (Note that the question relating to implications for water security will be
addressed in collaboration with the PostDoc on sub-project 3)
Sub-project 2: Testing the hydrologic validity of downscaled climate data
Uni of Newc Staffing: 1 x Phd supervised by GW, AK (DVK?? GK??)
The use of the downscaling climate set for hydrology will need to be stochastic. The simulations for
the future are not deterministic forecasts but stochastic simulations that should have the correct
statistical properties. Thus it’s important that the statistical properties of the (climate/hydrology)
dataset are correctly reproduced for the historical data. Deterministic reproduction would be good
but statistical is crucial. Hydrology assessment here means both drought and flooding. In this sub-
project we will concentrate on the two extremes rather than the entire range of time series.
Experience with stochastic rainfall simulators has shown that while rainfall statistics might be
adequately simulated the runoff statistics can still be poor. We will validate the downscaled
hydrology by doing a range of simulations for a variety of size catchments, from north to south and
with different exposure to the coast and wind. The catchment used will be ones where we can also
generate a dataset with ground observed data sets so we can compare ground based
measurements with the downscaled predictions. Standard runoff statistics will be used but also we
will run the results through a variety of reservoirs systems of various sizes to look at the
reproduction of long term persistence in the datasets. We will also look at reproduction of various
measures used for demand management of urban water (e.g. trigger levels on reservoir systems).
This latter validation will be done in close consultation with urban water partners (Hunter Water) to
provide domain specific validations.
Also assessed will be the hydrological benefit of downscaling to a fine resolution. This will be done
by comparing 10 km versus 2 km NARCliM downscaled information and how they, when use as
climatic inputs for hydrological modelling, reproduce the various hydrological statistics.
Comparisons could also be made between dynamically downscaled and statistically downscaled
information (if Ashish’s statistically downscaled info is made available to us).
No future projections are considered in this sub-project.
PhD Novelty (the research questions that ARC will be looking for):
The validation of a downscaled dataset for hydrology reproduction is not entirely new but the
availability of the entire coastline from N to S allows us to more closely examine potential
physical drivers to rainfall/evaporation behaviour. For instance does the combined effect of
mountains and coastal winds have an impact at the escarpment on statistical reproduction.
Is there a difference in statistical reproduction based on the ocean modes?
The validation of the hydrology on the urban water system behaviour is new and has not
been done previously and is likely to lead to new insights to do with reproduction of long
term persistence and robustness of urban water systems (we might see different system
behaviour based on subtle differences in the measured and predicted hydrology).
The combination of downscaling, hydrology prediction, and examination of the resolution
and scale dependence of hydrology statistics is new. This will lead to insight in the validity of
the act of downscaling on hydrology statistics from the downscaled climate (is the output of
downscaling “real” or just “false precision”?). It will help to answer questions about how fine
a resolution is needed for hydrology assessment, and the incremental value of the
downscaled product for hydrology assessment.
Sub-project 3: Assessing the impact of ECLs on water security and how this might change
Uni of Newc Staffing: 1 x Postdoc with assistance from GW, GK, AK, DVK
This sub-project is where the outcomes for the industry partners are well defined, where the
research requires a degree of sophistication not typically available at PhD level and where
considerable interaction is required with the industry partners.
We will select 4 case studies to be studied in detail for historical (instrumental and maybe
palaeo) and future conditions. The future conditions will be based on the downscaled
GCM/RCM outputs of NARCliM (UNSW collaboration and in-kind - ESCCI project 2) and
insights from the BoM ECL model and the paleo-data on ECLs occurrence (ESCCI project
1, 3 & 4). The 4 case studies are:
o The Sydney Water urban system. GK has a headworks model (network optimisation
code) for the Sydney system but it was developed for the SCA. It will require the
agreement of SCA to release the model for this project. Otherwise we will construct
our own (though this is a major task and we will likely only be able do a simplified
version in time allowed). SCA will provide models and data.
o The Hunter Water urban system. There exist two models for the system currently
available and each has particular advantages. GK has a network optimisation code
while Brendan Berghout has a more traditional operations rule based model. It is not
clear which model to use and it is not clear we need to decide before the grant goes
o A north coast catchment (Coffs Harbour? Port Macquarie?). If drought is driven by
ECL frequency it conceivable that the N Coast might be relatively less sensitive to
southern bounds of the warm currents. I think also Pete Smith said there are
emerging problems for Coffs so it makes a good study.
o A south coast catchment. There are no obvious candidates but since it is
conceivable that this area might be most sensitive to ECL frequency changes
(because its near the existing southern boundary of ECL occurrence---to be
confirmed by sub-project #1) a catchment should be studied. This might be the
opportunity to look at an isolated irrigation type dam rather than multi-dam urban
systems. Perhaps we could look at catchment pre- and post- an irrigation dam.
Another possibility is to perhaps look at one of the Canberra dams (even though they
are in Murray Darling they are on the eastern side of the Alps so are probably
Eastern Seaboard Climate???—to be investigated by sub-project #1).
• What exactly do OEH, NoW and Hunter Water want?
• Can NoW identify how they might like us to assess changes in extra-urban
water security changes due to ECL occurrence and climate change?
Research Novelty (i.e. for ARC)
o Methodology for using GCM data for quantitatively assessing the reliability of water
supply system on Eastern Seaboard. We will no doubt learn a lot about the use of
dynamical downscaled data and the effect of climate resolution effects on hydrology
o Address concerns raised in the “Biophysical Scan” that GCM output are inadequate
for assessing climate change impacts on water resource. This will be first time in
Australia dynamical downscaled climate data will be used for assessing hydrology
and water security.
o The role of ECLs in determining the robustness of our water supply systems and the
potential impacts that climate change will have on them
UoN: Anthony Kiem, Garry Willgoose, Danielle Verdon, George K
OEH: Fei Ji
NoW: Shahadat Chowdhury
BoM: Aaron Coutts-Smith, Acacia Pepler, Agata Imielska
HWC: Brendan Berghout
SCA: Jason Martin, Mahes
OEH: 0.9 EFT/yr for 3 years
NoW: 0.2 EFT/yr for 3 years
BoM: 0.2 EFT/yr for 3 years
SCA: 0.1 EFT/yr for 2nd and 3rd years
Partners: Cash = $170k
In-kind (other ESCCI/NARCliM projects) = ~$3,000k
In-kind (models and data from SCA and HWC) = TBA
In-kind (BoM, OEH, NoW staff on this project) $120k x 3yrs = $360k
ARC ask = $530k
Total cash = $170k + $530k = $700k
$$ required for PhD, Post-doc salary, on-cost and expenses
2 x PhD = 40k each/year for 3 years (including expenses) = $120k x 2 = $240k
1 x Post-doc = $120k/year for 3 years (including expenses) = $360k
Travel, equipment, data, publication costs = ~30k/yr = = ~$100k
Significance and Innovation
In final application will clearly highlight that this work is complementary to existing work (BoM,
UNSW, SEACI etc) and not in competition. Even though others are looking at ECL the objectives
and/or approaches and/or datasets are different hence multiple lines of independent enquiry
(=robust and unbiased research insights and indication that the issue is significant).
Beyond the science significance of this specific project the findings will also be used in upcoming
Sydney Metro Plan (Collette) which will lead to further industry investment and the implications go
beyond water security. Several biological problems that require info that will be produced here and
so there is wider scope along the lines of climate change and aquatic biology (Pete Smith), climate
change and flood risk (Duncan McClucky), estuarine health, bushfire, urban growth, agriculture,
Linkage Projects 2012 (Round 2) Timeline
Due at Research Office
Eligibility Exemption Requests 10am on 22 September 2011
Draft Applications 10am on 19 October 2011
- No paper copy required, but pdf copy must be emailed to
- All sections of the application must be shown as 'Valid' in
RMS in order to be reviewed.
Final Applications 10am on 7 November 2011
- Submitted to 'Research Office' in RMS
Certification Form/Email 10am on 7 November 2011
ARC Closing Date 5pm on 16 November 2011