Bulletin vol 25 no 3 june 2012

AMOS

AustralianMeteorological & OceanographicSociety

Bulletin of the Australian Meteorological & Oceanographic Society Vol 25, No.3, June 2012 ISSN 1035-6576

Contents Editorial ..........................................................................................................................................................................40 President’s Column ........................................................................................................................................................41 News ..............................................................................................................................................................................41 News from the Centres ..................................................................................................................................................42 Conference report ..........................................................................................................................................................43 Obituary — Neil David Adams ....................................................................................................................................44 Phone Application Review — Coton App....................................................................................................................45 Articles ...........................................................................................................................................................................47 J. Allen — Supercell Storms: Melbourne’s White Christmas 2011 .......................................................................................47

Meet a Member .............................................................................................................................................................52 Snapshot ........................................................................................................................................................................53 Charts from the Past with Blair Trewin: 18 July 1917 ...................................................................................................54 Calendar .........................................................................................................................................................................55

ISSN 1035-6576 Cover picture: A hail stone that fell in Keilor in the north-western suburbs of Melbourne on 25 December 2011. For more information on the 2011 Christmas Day storms turn to page 47. Image: Gareth Berry.

Unless specifically stated to the contrary, views expressed in the Bulletin are the personal views of the authors, and do not represent the views of the Society or any other organisation or institution to which the author(s) may be affiliated.

Editorial

Severe storms and tornadoes in Australia Reading through the article on the 2011 Melbourne Christmas Day storms by John Allen (see page 47) reminded me of my own experience of the storm and prompted me to look into some of the events that day and have a look at some of the history of severe storms and tornadoes in Australia.

From my own personal account, the storms (luckily for us) arrived after we had finished our Christmas Day barbecue but they completely devastated our attempted game of cricket (it turned out that we had tried to play between the fi rst and second storms). The situation was declared unplayable due to a combination of the pitch turning into a stream, lightning instantaneously followed by thunder and the disintegration of our Christmas-cracker hats. It turned out that we were ‘lucky’ to be on the south-eastern side of the storm and we were ‘only’ caught out by the heavy rain and lightning beneath the anvil.

However, many other areas were not as relatively fortunate and suffered a large amount of property damage. There was also interesting footage of a fire-truck crossing flood water (http://www.youtube.com/watch?v=LCm66l0FSNQ), which highlights the large amount of water that was dumped on Melbourne and its surrounding suburbs that day. While the footage can be considered amusing in some regards, it is concerning that the flood waters impeded the operations of the emergency services.

Other significant features of Melbourne’s Christmas Day storms were large hail (see the front cover) and the presence of at least one tornado (see John Allen’s report on page 47), which got me wondering how regular tornadic storms are in Australia. I was also intrigued to fi nd out whether Melbourne and its surrounding suburbs have suffered similar events in recorded history (an answer I was almost certain would be yes).

A quick look on Wikipedia (http://en.wikipedia.org/wiki/ List_of_Southern_Hemisphere_tornadoes_and_tornado_ outbreaks) revealed an average of approximately 20 tornadoes per year recorded in Australia and gives a list of several significant events. Interestingly, the first event on the list is one that affected one of the south-east suburbs of Melbourne and was known as the “Brighton Tornado,” which occurred on 2 February 1918. The tornadoes on that day caused two deaths and several injuries, with the strongest tornado rated as F3 (254–332 km hr-1 winds) on the Fujita Scale of tornado intensity.

The Bureau of Meteorology also has an interesting site dedicated to severe weather in Victoria

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 40

(http://reg.bom.gov.au/vic/sevwx/) and states that there have been “160 tornado reports dating from 1918,” (approximately two per year) but also states that “it is most likely that many tornadoes have gone unsighted or unreported,” which suggests that the 20 tornadoes per year given above is likely to be a conservative estimate for Australia as a whole.

The Bureau of Meteorology also hosts severe thunderstorm information for New South Wales and the Australian Capital Territory (http://reg.bom.gov.au/nsw/sevwx/) and Western Australia (http://reg.bom.gov.au/wa/sevwx/).

The New South Wales / Australian Capital Territory site states that “the Bureau of Meteorology’s database records 364 tornadoes across New South Wales from 1795–2003.”

These records further indicate that tornadic storms are a regular feature of Australian weather.

So my quick look at the web has revealed the prevalence of tornadic events in Australia, and with the low population densities throughout much of the country, the estimates of the number of these events on average per year are likely to be lower than the actual number of events.

Despite the devastation of the Christmas Day storms (and other past severe weather events in Australia) there is something you can do to help. By becoming a member of the Storm Spotter Network (http://www.bom.gov.au/storm_spotters/index.shtml), you can provide the Bureau of Meteorology with observations of severe storms and tornadoes. The requirements are that you reside in Australia and that you are at least 18 years old. You can fill out an application from (available on the web site) and send it to your local Bureau of Meteorology regional office. Once registered you are asked to report to the Bureau of Meteorology if you experience or you are made aware of any severe weather (large hail, strong winds, tornadoes and heavy rain). With the increasing ease of access to the internet through mobile phones, such a scheme is invaluable in providing an early warning to people of an impending severe storm. The network will also help to develop a better estimate of the frequency and locations of such storms when more people are involved.

While it will not prevent severe storms from causing damage, a good early warning network can at least help to mitigate their effects on lives and property.

Duncan Ackerley

President’s Column

Australian atmospheric and oceanic science

The run-up to an Intergovernmental Panel on Climate Change (IPCC) deadline is always a time when there is lots of frenzied scientific activity. Last time round, at least a third of the lights were still on in the Centre for Australian Weather and Climate Research (CAWCR) at 9 p.m. on submission deadline day, and I don’t expect that it will be greatly different this time.

It is a time to take stock of just how much good science is being done in Australia. I had a bit of a taste of this recently when attending the annual review meeting for the Australian Climate Change Science Plan in Hobart (held in May), and I heard how much was happening in just one corner (albeit a very high-profile corner) of the science landscape in the atmospheric and oceanographic sciences. One area in which we can be especially excited is the work being done towards Australian contributions to the 5th Coupled Model Intercomparison Project (CMIP5), and the role that the Australian Community Climate and Earth-System Simulator (ACCESS) model is playing in this. Results presented at the meeting indicate that ACCESS is amongst the best-performing of the current generation of climate models for a variety of measures—a very impressive effort. Australian contributions to CMIP5 will be the subject of a special issue of the Australian Meteorological and Oceanographic Journal early next year, so you’ll be able to read much more about the work then (also see the article by Collier et al., 2011, which appeared in the October 2011 issue of BAMOS – Ed.).

If that meeting was the showcase for one particular section of the sciences which we cover, our National Conference is the showcase for all of them. Following the successful

2012 conference, planning is now well advanced for the 2013 National Conference in Melbourne, which we are hoping will be at least as big as this year’s (see the advert on page 46 for more information – Ed.).

We do not yet have a venue for National Conferences from 2014 onwards and would welcome expressions of interest from Regional Centres, especially those that haven’t hosted one in recent years or are yet to do so at all. I’m currently in the process of travelling around (most of) the country and meeting with as many Regional Centres as possible. Outside the largest centres, the Regional Centre groups may be relatively small, but the ones I’ve met with so far have at least a good core of enthusiastic people who are doing their bit to make AMOS a vibrant organisation throughout the country. Regional Centres who might be interested in hosting a National Conference but aren’t sure whether they have the people to handle everything can be assured that the national organisation can provide a lot of support if it is needed.

A fi nal reflection also comes from the Hobart meeting, which occurred shortly after some front-page coverage of some very amateurish data analysis in our fi eld. The point was made that if something like this happened in medicine, the Australian Medical Association would be open in expressing their outrage. The major institutions have shown a reluctance to enter this space; I am interested in the thoughts of members as to whether AMOS as an organisation should get involved in responding to material such as that, and if so what our processes for doing so should be.

Blair Trewin

News

Short Films Big Success—Green Screen: Climate Fix Flicks Joshua Cockfield

University of Melbourne Address for correspondence: jcoc@unimelb.edu.au In late 2011, climate scientists from Macquarie University, the University of Melbourne and Monash University joined forces to launch an innovative project: a short film competition that raises awareness of climate change and the benefits of moving towards a low carbon future.

Dubbed Green Screen: Climate Fix Flicks, the competition was the brainchild of well-known climate scientists David Karoly, Ann Henderson-Sellers and Dave Griggs. The key aim of the project was to promote positive messages of change through the popular medium of film.

Films were to be a maximum of five minutes in length and participants were encouraged to push creative boundaries.

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 41

The filmmaking community did not disappoint with films including everything from zombies to rapping grandmas.

Eleven films were shortlisted and screened at a public event in Sydney as part of the Australian Film Festival in March 2012. The shortlisted films were judged by a panel of well-known artists, scientists, filmmakers (including Kimble Rendall—Matrix and I, Robot) and Lesley Hughes (Climate Commission), with both Lesley Hughes and Kimble Rendall commenting on the high standard of films in competition. A team from the USA affiliated with San Jose University took out the grand prize worth $5000 and a young creative team from Sydney won the ‘Event Cinemas’ Prize for ‘Best Entry from NSW’.

There is now an opportunity for the public to choose their favourite film through the online viewing and voting system that was launched last week: http://greenscreen.herokuapp.com/. The winner of the people’s choice award will receive $5000.

screenings suggests that these types of short films are a popular and highly accessible communication tool.

The Green Screen fi nalist will hit the big screen again in late June as part of the Dungog film festival in NSW (Saturday 30 June). Victorians will also get the chance to see them in a cinema in late August (date and location to be confirmed).

The shortlisted films have been in high demand both in Australia and overseas. The films were screened at the 2012 Planet Under Pressure conference in London. The demand and positive feedback that has followed the

Grand prize being accepting by a relative of the winner. Image: Dr Kendal McGuffie (UTS).

News from the Centres

Melbourne Centre News Luke Hande and Nicholas Tyrrell

Regional Sub-editors, Melbourne World Meteorological Day 2012 was marked by the launch of the Australian Climate Observations Reference Network - Surface Air Temperature (ACORN-SAT) data set at the State Library of Victoria. The Bureau of Meteorology and AMOS hosted this event, which featured presentations from prominent scientists involved with the inception and review of the new high quality temperature data set.

ACORN-SAT consists of surface temperature observations from 112 stations across Australia from 1910 onwards.

The stations were chosen to maximise the length of the record and the spatial coverage across the country. The data set has been designed to take the place of two current temperature data sets – the annual data set from 1910 to present, and the daily measurements from 1957 to present.

Nearly all of the temperature records in ACORN-SAT required some level of homogenisation in order to remove influences from changes in instrumentation, site location, the effects of surrounding buildings and other nonclimatic factors. Inhomogeneities were identified using a combination of metadata and statistical methods. The digitisation of the pre-1957 data, and the homogenisation of the temperature records give ACORN-SAT the ability to better represent long term surface temperature trends across Australia.

Mr Ken Mathews, chair of an independent international panel, which reviewed the data set, spoke about the review process. After examining the methods employed by the Bureau of Meteorology to maintain a homogenised

temperature record, the panel was satisfied with the techniques used to develop ACORN-SAT. The panel ranked the Bureau of Meteorology’s procedures and data analysis as amongst the best in the world.

Professor Neville Nicholls, from Monash University, spoke about the history of high-quality datasets in Australia. He began by showing examples of changes in instrument exposure, which make it important that these changes are accounted for in order to develop a high quality data set. Professor Nicholls pointed out that a major motivator of developing ACORN-SAT was to ensure good quality data was available to researchers, as well as freely available to the public. Additionally, making the original data available to all who want them, ensures transparency of the processes involved in developing the new data set.

Drs Bruce Forgan, Blair Trewin and Robert Fawcett, from the Bureau of Meteorology, spoke about the practice of measuring temperature in Australia, from the early days of manual mercury or alcohol thermometer measurements to the introduction of automated weather stations. They spoke about the science behind how the data is compiled, and the analysis of warming trends from a range of data sources for Australia.

ACORN-SAT has already proven itself as a reliable data set, confirming climate trends previously identified in Australia. The new data shows that Australia has warmed by approximately 1°C since 1910, with most of the warming occurring since the 1950s.

NSW Centre News Fiona Johnson

Vice Chair and Publicity, NSW Centre The NSW AMOS Centre is looking forward to hosting two exciting events in July. On Monday 2 July, Francis Zwiers will be presenting a seminar on “Progress in Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 42

Detecting Anthropogenic Influences of Temperature and Precipitation Extremes.” The talk will describe several approaches that have been proposed to assess whether

there is a detectable human influence in the far tails of the distribution of climate variables such as daily maximum air temperature or daily precipitation amount. The talk will also cover initial applications of these approaches, and discuss limitations and further areas of improvement.

The seminar will be held at the Climate Change Research Centre at the University of New South Wales (UNSW).

After a successful inaugural AMOS NSW postgraduate research symposium in 2011, the 2012 symposium has been organised for Friday 20 July at the Climate Change Research Centre at UNSW (see flyer on page 53 – Ed.).

This event will give postgraduate students working in meteorology, oceanography or climate research the opportunity to share their research with other students and hone their presentation skills in a presenter-friendly environment. Students will also pick up tips and advice

that they may find useful in their studies and future careers from Prof. Andy Pitman, Director of the Australian Research Council (ARC) Centre of Excellence for Climate System Science and Dr Sarah Perkins, a postdoctoral researcher at UNSW. The program for the day will include talks by Andy and Sarah, 15 or 20 minute talks by student attendees and free lunch and morning and afternoon tea, kindly sponsored by the ARC Centre of Excellence for Climate System Science. A prize will be awarded for the best student presentation. Seating and speaking slots at the symposium are limited and will be allocated on a firstcome-first-served basis, so get in quickly! Details on the symposium are on the NSW Centre section of the AMOS website.

Symposium details can be www.amos.org.au/documents/item/625

found

at:

Brisbane Centre News Michael Hewson

Secretary, Brisbane Regional Centre Some 20 people of the Brisbane Regional Centre gathered in the Bureau of Meteorology conference room at lunchtime on Thursday 12 April 2012 to hear our AMOS President, Dr Blair Trewin, talk about “a new longterm daily temperature data set for Australia.” It was a thoroughly interesting talk which illustrated the immense effort agencies, researchers, and people like Blair, expend to ensure data and scientific integrity.

I could not help but reference this talk during the recent Australian Broadcasting Corporation TV program, “I can change your mind on climate change,” which aired some repartee concerning the location of weather stations by folks who clearly don’t attend this sort of factual presentation—but hey I digress.

Our thanks to Blair for spending some time with us in Brisbane. More news will be given to the Brisbane members soon about a future gathering.

AMOS president Blair Trewin at a Bureau of Meteorology observation station. Image: Blair Trewin.

Conference report

10th International Conference on Southern Hemisphere Meteorology and Oceanography: Changing Southern Climates.

23–27 April 2012, Noumea, New Caledonia Jennifer Catto

Monash University, Clayton, Victora.

For five days at the end of April, the Pacific Island nation of New Caledonia played host to approximately 300 delegates for the 10th International Conference on Southern Hemisphere Meteorology and Oceanography (ICSHMO). The conference was held at the spectacular Tjibaou Cultural Centre in the capital city of Noumea.

This was the fi rst time the ICSHMO had been held in a Pacific Island nation, having previously been held in Brazil, New Zealand, Argentina, Australia, South Africa and Chile. The theme of the conference – Changing Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 43

Southern Climates – is especially relevant to islands such as New Caledonia, which face an uncertain future with respect to sea level rise, cyclones, droughts and floods.

The Tjibaou cultural centre, also called Ngan Jila (House of Wealth) in the local pije language, was created in 1988 to enhance Kanak cultural heritage. On the fi rst morning of the conference, the director of the cultural centre welcomed the delegates, who had come from all over the world, in a traditional welcoming ceremony.

The President of the Government of New Caledonia,

Harold Martin, also welcomed us and encouraged us in our work to understand changing Southern Hemisphere climate and what impacts that may have on countries such as New Caledonia, and also the whole of the Southern Hemisphere.

University of Tasmania on the evolving state of the Southern Ocean. The evening cocktail reception provided a fantastic opportunity for everyone to meet and discuss talks and posters while being entertained by traditional music and dancing, and refreshed with food and drinks.

Through the week, there were 17 different plenary and parallel sessions covering climate variability of the atmosphere and oceans, observations and climate change.

On the first day of the conference, two sessions were held to honour the work of scientists who have made outstanding contributions to advancing Southern Hemisphere atmospheric and oceanic science. The fi rst of these was given by Dr Arne Biastoch to honour Johan Lutjeharms, who was a leading South African marine scientist with a specialisation in the Agulhas Current system, which lies to the south-east of South Africa. The second of these was in honour of (and presented by) Pedro L. Silva Dias where he spoke about his work on the South American monsoon system. Later in the day, after some very interesting parallel sessions, there was a special icebreaker and poster session sponsored by the Pacific Australia Climate Change Science and Adaptation Planning Program, where many of the scientists from the Pacific Islands presented work on the climate variability of their countries and potential climate change impacts.

The fi nal day of the conference was nearly missing its invited speaker, after Jerry Meehl from the National Center for Atmospheric Research (NCAR) in the United States of America, and others, were stranded by a slight misunderstanding with the buses. However, everyone arrived in time and enjoyed the presentation on decadal climate variability. After more very interesting parallel sessions and a poster session, the conference was brought to a close by the local organisers. This included presenting the winner of the student poster competition with a prize of 1500 Euros to assist with travel to another conference.

A fantastic prize, and the winner was Katherine Sadler from Melbourne University (watch this space for an article

by Katherine on her award winning work – Ed.).

On day two of the conference, the parallel sessions continued in the morning. An invited talk by David Karoly from Melbourne University in the afternoon gave a history of the ICSHMO conferences (all of which he has personally attended) and the science that held focus at each of them. Th is was a fantastic reminder of how far Southern Hemisphere climate science has progressed in the past 30 years, and for me personally, was a great inspiration.

The morning of day 3 consisted of parallel sessions focussing on tropical cyclones, Southern Hemisphere convergence zones, and Southern Hemisphere ocean circulation. The afternoon was left for free time, and many conference delegates used the time to relax at the beach or do some snorkelling in the coral reef lagoon.

Day four was a very busy day with parallel sessions containing a great number of talks in the morning, followed by a plenary talk by Nathan Bindoff from the

Altogether, the conference was a great opportunity for scientists with a special interest in the climate of the Southern Hemisphere to join together and the setting of the Tjibaou cultural centre was wonderful. Many thanks are due to the local organising committee, the program organising committee and all others who helped to make the conference such a success.

Musical entertainment from local performers during the welcoming ceremony. Image: Tess Parker.

Obituary

Neil David Adams—“Antarctician” extraordinaire Steve Pendlebury

Australian Bureau of Meteorology Dr. Neil David Adams died on 23 March 2012 after a very brief illness. AMOS stalwart, Dr Mike Pook, summed up Neil’s achievements and character with the following words: “From his first day at the Hobart Weather Bureau nearly 30 years ago, Neil impressed with his drive and enthusiasm. These qualities characterised Neil’s approach to his work throughout his career and inspired his colleagues. Neil has made a major contribution to Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 44

Antarctic meteorology with his rare talent of being able to move comfortably between the operational and research environments. But above all, he was a great colleague and a decent, friendly person.”

At a Hobart celebration of Neil’s life on 29 March, we heard from Neil himself, thanks to the career outline he had written for a Bureau of Meteorology Centenary ‘time

capsule’ in the Hobart office: “I joined the Bureau in 1982 on Met Course 30, and then transferred to Hobart where I worked mostly on shift, for four years. In 1987 I had a nine-month break to complete a Diploma of Education, and in early 1988 I resigned to travel around the world.

After six months of travelling and a year working as a contract programmer in Sydney, I rejoined the Bureau in 1989 working shifts in the Victoria Regional Office, with stints in the newly formed Severe Weather Section.

In 1991 I won the Bureau scholarship to do my MSc at Monash University. In 1992 I was promoted to the Bureau position at the newly formed Antarctic CRC at the University of Tasmania, commencing applied research into Antarctic weather, and playing a role in managing the Antarctic Meteorological Centre at Casey Station.

I was privileged to spend the 1992/93 summer at Casey as the OIC of forecasting, followed by a winter stint in 1994 as a research meteorologist. Th is was a fantastic experience, although long at 19 months (in duration), as I worked as the OIC forecasting for the 1993/94 and 1994/95 summers as well. Two more summer stints followed over the 1997/98 and 1998/99 seasons. In 2004 I graduated from the University of Tasmania with a PhD in Antarctic Numerical Weather Prediction and I currently manage the Antarctic Meteorological Section within the Tasmania/Antarctic Region. Working for the Bureau has been very rewarding with the variety of experiences, and people stimulating and engaging.”

Neil’s words do not begin to convey his tremendous capacity, capability and contribution to operational meteorology and, in particular to Antarctic science and services. For all these efforts, and many, many others the Bureau of Meteorology awarded Neil the Excellence Award for 2011. The following words from Dr Tony Fleming, Director of the Australian Antarctic Division (AAD) were shared with AAD staff following Neil’s passing—they highlight why Neil was so deserving of the Bureau award: “Neil has played an important part in our program for nearly three decades on a lot of fronts from world renowned scientific research to critical support of our logistical operations. On the scientific front his work on the international stage in the area of Antarctic and Southern Ocean meteorology is of the highest calibre and deemed by his peers to be at the forefront of the field.

He was known for his hard work and the relationships he built with other scientists in Australia and overseas,

especially through his work in the World Meteorological Organisation. But he also established a special relationship with personnel working on our stations, in the deep field, at sea and in the air across Antarctica. Another facet of Neil was that he had a special affinity for students that came to learn from him, inspiring them with his passion for all things Antarctic, which will leave us with a continuing legacy of meteorologists and climate scientists with a sharp focus on Antarctica. You will all be aware that Neil’s work plays a critical role in helping us achieve our operational objectives across the continent. There was many an activity that would rely on one of Neil’s expertly crafted forecasts before commencing. Th is included resupply operations and myriad aviation activities. It wasn’t unusual for Neil to be at his computer running weather models at 2am in the morning in support of an emergency response, showing his deep affinity and care for those working in Antarctica.

His work over the last three decades has made all of our activities intrinsically safer.”

Acting Director of Meteorology, Dr Rob Vertessy, in a condolence message, spoke for all who knew Neil: “We will miss your brilliance and dedication Neil, but most of all we will miss “just you” .”

Neil is survived by his wife Kathy, children Eliza and Harrison and step-children Liam and Rachel.

Neil at his desk, circa March 2010: Antarctic work fills his computer screens.

Image: The Mercury.

Phone application review

Coton: The cloud identification smartphone application Linden Ashcroft

Melbourne University, Melbourne, Victora.

You know the scenario: You’re walking along with some friends, minding your own business, when someone spots an interesting cloud in the sky. “You’re a weather nerd,” they say, “what’s that cloud? Does that mean it’s going to rain tomorrow?” Panicked, you delve into your undergraduate knowledge and pull out something that Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 45

sounds meteorological: “Yeah, that’s an, um, altostratus cloud. I think it means…snow?”

Well fear that situation no longer! Now there is an “app” for it. Coton, the cloud identification smartphone application developed by Etamin Studios, will alleviate all of those

awkward conversations and help you (and your friends) to answer those curly cloud questions.

Coton is a sleek, simple application for your iPhone, iPod touch or Android smartphone that allows you to identify clouds with a swish of your fi nger. It features photos of all the major cloud types, along with a description of how each cloud forms, its height, and the weather that generally accompanies it. You can scroll through photographs until you fi nd the one that matches what you are looking for, and then search through the species and varieties of that cloud (i.e. cumulus, cumulonimbus, pyrocumulus) quickly and easily.

The information provided—sourced from the International Cloud Atlas—is concise, and the images are stunning, even on a small screen. While some of the details might not be enough for avid cloud spotters, there is definitely enough information in the descriptions to assist most enthusiasts.

what you are seeing in the sky. Sadly you cannot add your own photos to the application, but the “More about Clouds” section points you in the direction of cloud appreciation webpages and societies where you can share your own shots and love of clouds (I personally recommend visiting the ‘clouds that look like things’ section of the Cloud Appreciation Society’s web site – Ed.).

The application also gives a succinct and easy to understand graphical description of how and why clouds form, which is great for novices and lazy meteorologists alike. Additionally, there is a resources section that contains a solid list of websites and books to quench your desire for more cloud knowledge. On top of all this, the application is very stylishly designed, making it a joy to use and share with others! If you have ever been stuck struggling to separate your cumuli from cirri, this is the application for you.

COTON is available from: http://cotonapp.com/

There are several photos of each cloud type provided, giving you a much better chance of correctly identifying

AMOS Annual Conference 2013

Sense and Sensitivity: Understanding our Changing Climate Melbourne Convention & Exhibition Centre , 11-13 February, 2013

Our weather and climate is changing, and so is the working environment for Australian meteorologists, climatologists and oceanographers. The 2013 AMOS Conference will focus on developments in our understanding of the physical climate system and review the required skills and knowledge of professionals working in the field.

Major topics include: -

AMOS

Climates of the past and projections for the future Variability of atmospheric and oceanic processes at different scales Model development: enhancing our understanding of the climate system Scientific computing and the 21st century meteorologist, climatologist and oceanographer

AustralianMeteorological & OceanographicSociety

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 46

For further information email: admin_officer@amos.org.au www.amos.org.au

Articles

Supercell Storms: Melbourne’s white Christmas 2011 John Allen

School of Earth Sciences, The University of Melbourne Address for correspondence: JohnTerrAllen@gmail.com

1. Introduction Large hail is not unusual for Australia and is often the result of supercell type thunderstorms (e.g. The 1999 Sydney Hailstorm, Yeo et al. 1999)—storms that feed off both the vertical shear of the horizontal wind and instability of the atmosphere (Weisman and Klemp 1982). These storms are long-lived (>1 hour) thunderstorms with an associated rotating updraft known as a mesocyclone1 (Davies-Jones et al., 2001). The combined sources of both rotational and buoyant energy mean that a disproportionate share of severe weather results from these storms (Doswell, 2001). In Melbourne, supercell storms are somewhat less common than Brisbane or Sydney, and large hail events are relatively rare compared to other parts of the east coast. On 25 December 2011 the synoptic environment was primed for the development of severe storms in the Melbourne region with a large degree of instability and vertical wind shear associated with an upper level shortwave trough passing through the area. What resulted was an impressive supercell thunderstorm event, with widespread damage through the Melbourne suburbs, including tornadoes, damaging winds and hail up to the size of tennis-balls.

2. Synoptic and environment analysis Two days prior to the event, it was clear that the environment would be primed for significant severe 1 A mesocyclone refers to the storm scale rotation within supercell storms that stretches through a large portion of the updraft (Davies-Jones et al., 2001), which acts as the parent rotation to tornadoes. The presence of a distinct mesocyclone is a defining characteristic of supercell storms.

When these rotations wrap precipitation around the updraft they can occlude and cut off the flow of warm moist air into the storm, effectively strangling it.

(a)

thunderstorms, with lifted indices2 as low as -10°C, and vertical wind shear through the deep layer (surface to 6 km) in excess of 50 knots in model forecasts. As the day evolved, it became evident that the area under greatest threat was Melbourne itself, rather than to west of the city, as anticipated by earlier model analyses. The dawn hours of Christmas Day were punctuated by lightning storms that produced heavy rainfall over the city and added to the already oppressive humidity in Melbourne from prolonged north-easterly flow. This flow originated from the sub-tropics from the combination of a blocking high in the Tasman and the approaching trough and weak low to the west of Melbourne (Figure 1a). The high levels of moisture, combined with vertical lapse rates in excess of 7.5°C km-1 (Figure 2) associated with an approaching upper level shortwave trough, generated substantial Convective Available Potential Energy3 (CAPE, in excess of 2000 J kg-1) by 3pm over the Melbourne area. Surface temperatures at this time were approaching 29.5°C and dewpoint temperatures were as high as 16°C. Storm development was primarily focused around a surface trough (Figure 1a, b) that was near stationary for much of the afternoon before slowly shifting eastward in the later evening.

2 The lifted index (Galway, 1956) in this case considers the temperature difference between the environment at 500mb and a surface parcel lifted to 500mb in the atmosphere for a point sounding. Values less than -2°C indicate the potential for thunderstorms, while values lower than -6°C indicate the potential for supercells and very severe thunderstorms.

3 CAPE (Holton, 2004) is a measure of buoyancy, determined using a vertical integration of the difference between the parcel and the environment, with large values corresponding to a potentially strongly unstable atmosphere.

(b)

Figure 1: a) 00UTC (11am local time) MSLP synoptic analysis showing the prefrontal trough over Tasmania and a second trough extending from a heat low in northwestern Australia to a weak low pressure centre over Victoria. b) 06UTC (5pm local time) MSLP synoptic analysis showing the surface troughs combined and low strengthening as the day evolved. This boundary would remain almost stationary over Melbourne between 3pm and 6pm local time. Source: The Bureau of Meteorology.

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 47

Figure 2: Modified 00UTC (11am local time) rawinsonde sounding for Melbourne Airport using observed maximum daily temperature and the corresponding dewpoint temperature. Environmental trace is in red, while the grey line indicates the modified parcel trajectory. Vertical axis is logarithmic pressure levels, with equivalent heights shown. Note the mid-level dry layer (dewpoint and temperature trace separation between 5 km and 8 km denoted by the green lines) and capping inversion that persisted until later afternoon (temperature of environment warmer than parcel between 1 and 2 km denoted by the black lines) and lapse rates in excess of 7.5째C km-1. Source: The Bureau of Meteorology.

Winds near the surface were 15-20 knots from the northsupercell #1 produced large hailstones (up to 6 cm in east (Figure 2) associated with the surface trough, backing diameter) over the northern suburbs (Figure 3). These to 30 knots westerlies at 750mb (2 km). The overlying caused significant damage to vehicles and some damage shortwave trough was associated with 55 knot winds at to houses and property. The storm began to weaken as 400mb (7 km) by late afternoon. With a strong vertical it encountered competition from the rapidly developing wind shear profile for left-moving supercells (i.e., strong second storm (Figure 4a), and was later absorbed by the deep layer shear with winds turning counter-clockwise larger cell. with height), a number of storms developed on the day.

The surface trough, now stationary over the northern parts of Port Phillip, proved a focusing point for the 3. Event Description development of subsequent severe thunderstorms. A Supercell #1 formed at approximately 3pm and the second storm developed near Laverton before colliding Bureau of Meteorology (BoM) quickly issued a severe with supercell #1 and a cell developing from the north, thunderstorm warning for the cell, indicating the potential before moving towards the east and becoming supercell #2 for large hail. Th is warning proved to be warranted as (Figure 4). This storm produced up to golf-ball sized hail

(a)

(b)

Figure 3: a) Supercell #1 over the northern suburbs with a strong hail and precipitation foot and with an exposed mesocyclone (the striated updraft in the centre of the photo). This photo approximately coincides with the production of giant hail over the northwestern suburbs of Melbourne. Image: Brad Hannon, taken from Mt Cooper, Bundoora looking west. b) Corresponding radar image for supercell #1, note the notched structure on the northern side of the storm associated with the observed updraft base. Source: Bureau of Meteorology.

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 48

(a)

(b)

Figure 4: a) Supercell #1 begins to weaken as the mesocyclone becomes more exposed. b) Supercell #2 begins to organize over the northern suburbs. The cell displayed a more classical supercell structure organization that was partly due to additional moistening of the boundary layer by Supercell #1 and strengthening north-easterlies. Images: Brad Hannon, taken from Mt Cooper, Bundoora.

(4.5 cm diameter) in the north and north-eastern suburbs metropolitan Melbourne (Figure 6) that persisted as the including Templestowe and Greensborough, along with cell moved across the city. very heavy rainfall and localized flash flooding and was a The supercell regenerated periodically (Figure 7), more “classical4” supercell storm. producing brief phases of movement to the northA third supercell formed further west of the city, near east and generating strong rotating wall clouds6 and Bacchus Marsh and rapidly developed a strong hook echo5 likely tornadoes near Melton and Mernda (Figure 8).

It later passed over the northeast ranges near Yan Yean structure (Figure 5a). Th is corresponded with a strong reservoir and continued towards Marysville. Th is longdoppler reflectivity couplet (Figure 5b) near Fiskville that lived cell also produced large hail and caused extensive was accompanied by the observation of a weak tornado damage associated with flash flooding and strong winds, that reportedly blew cars off the road. This prompted the particularly over the northeastern suburbs previously Bureau of Meteorology to issue a rare tornado warning for affected by supercell #2. Fortunately the tornadoes were either brief, or occurred over the sparsely populated 4 Classical supercell (Doswell and Burgess, 1993) refers to a conceptual grasslands and private property to the north of the major model of storm structure whereby a storm has a well organized suburbs (the tornado also passed between new housing mesocyclone with a significant precipitation core located downshear.

During the mesocyclone process this precipitation tends to wrap around the mesocyclone forming the characteristic hook echo.

5 Hook-Echo (Forbes, 1981) refers to the hook-like radar reflectivity signal that develops around a fully formed supercell mesocyclone. The clear area of the hook corresponds to the strongest updraft where little precipitation occurs. The hook itself arises from precipitation being drawn around the rotating updraft and is a strong sign of a supercell’s potential for tornadogenesis given sufficient ingredients.

6 Wall clouds are agglomerations of fractus cloud that form under the base of strong thunderstorms, and are structured depending on the strength of the storm. Weak wall clouds can look like scuddy cloud base and may not rotate, while strong rotating wall clouds are the lowering where tornadoes form under a thunderstorm. They arise from the cooling that occurs due to nearby precipitation from the downdraft. This causes the condensation of clouds at a level lower that the parent cloud base.

Figure 5: a) Composite reflectively (64 km) radar return from Laverton for the supercell #3 (SC3) near Fiskville at the time it was producing a weak tornado.

The structure is classic for a tornadic storm with the maximum reflectivity hooked around the storm’s mesocyclone on the north-western edge. Supercell #2 (SC2) can also be seen moving through the northeastern suburbs. b) Doppler reflectivity (128 km) for the nearest available scan to the composite reflectivity.

Source: Bureau of Meteorology.

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 49

THUNDERSTORM WARNING - Melbourne AREA for SEVERE DESTRUCTIVE WIND, FLASH FLOODING, LARGE HAILSTONES and TORNADOES For people in the Inner, Eastern, Northern, Western and parts of the South East, Geelong and Bellarine Peninsula, Outer East and Port Phillip Local Warning Areas.

Issued at 5:19 pm Sunday, 25 December 2011.

THIS INCLUDES A TORNADO WARNING. The Bureau of Meteorology warns that, at 5:10 pm, very dangerous thunderstorms were detected on weather radar near Bacchus Marsh, Greensborough, Hurstbridge, Lilydale, Yarra Glen and the area south of Bacchus Marsh. These thunderstorms are moving towards the east to southeast. Very dangerous thunderstorms are forecast to affect Deer Park, Healesville, Melton, St Albans, Sydenham and the area south of Melton by 5:40 pm and Craigieburn, Essendon, Footscray, Melbourne Airport, Preston and Sunbury by 6:10 pm.

Destructive winds, very heavy rainfall, fl ash fl ooding, large hailstones and tornadoes are likely.

A tornado has been reported near Fiskville (15km west of Bacchus Marsh) associated with the thunderstorm currently south of Bacchus Marsh. Very large hail has been reported with thunderstorms this afternoon.

Figure 6: The Severe Thunderstorm warning issued for Melbourne area with included tornado warning to address the reported tornado with supercell #3. Source: Bureau of Meteorology. developments). Supercell #3 also caused significant damage along the Tullamarine freeway with at least a hundred trees felled or snapped over a four-kilometre swathe.

At this time the surface trough began to slowly move northeastwards and a new supercell (#4) formed in the Mount Macedon area. Th is storm moved towards Broadford and quickly produced a hook echo and strong doppler reflectivity couplet7, with a strong associated wall cloud before moving over the Dividing Range (Figure 9). As the trough moved off to the north-east, a further supercell was observed in the fading light near Wandong in the wake of the earlier large storms (Figure 10).

4. Discussion A number of factors made this event unusual for Melbourne and Australia. The presence of both strong instability and vertical wind shear is relatively rare, particularly at latitudes as far south as Melbourne in the Southern Hemisphere. With the dry mid levels and steep lapse rates, large hail production was very likely with any strong storm that developed on the day. Additionally it is likely that (at least locally) north-easterly winds feeding the storms

Figure 8: A large collared cone circulation appears from behind the rear flank downdraft of supercell #3. This was the likely source of tree damage, the destruction of a shed and a small damage to a number of houses near Mernda. Image: Brad Hannon, taken from Donnybrook road looking southeast. were stronger than rawinsonde observations and model predictions, with eyewitness descriptions (from those in the path) of winds close to 30 knots. Further moistening of the environment by the strengthening north-easterlies likely contributed to the increased tornadic threat experienced from supercell #3. The tornadoes were most likely restricted in their life cycle by the parent storms’ heavy precipitation cores (so-called high-precipitation supercells; Moller et al., 1990), that tended to wrap around the low-level circulations. Interestingly there is some indication of longevity in the wall cloud cycle that occurred as the storm passed near Mernda, with the circulation not fully occluded. This circulation persisted for some twenty minutes, which is noticeably longer than the average lifetime of a tornadic circulation (Davies-Jones et al., 2001). The trough boundary also played an important role in the development of the relatively unusual occurrence of multiple supercells ‘training’ through the Melbourne area, with the surface outflow and precipitation mainly confined to the south of the boundary. Th is allowed the environment to the north of the boundary to remain largely unaffected by the passage of the earlier storms. The evolution of this feature meant that the overall scale of the ongoing event was difficult to anticipate and provided a

7 A Doppler reflectivity couplet is the close proximity of winds diverging and converging with the radar generating a two-colour pole.

When located in the non-precipitating/weakly precipitating area of a thunderstorm this can be used to identify the thunderstorm to have a mesocyclone and that the storm is rotating.

Figure 7: Supercell #3 producing a wall cloud near Melbourne airport.

During the later stages of this phase it produced a second brief weak tornado. Image: Brad Hannon, taken from road north of Melbourne Airport, Tullamarine.

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 50

Figure 9: Large low hanging wall cloud near Broadford produced by supercell #4. It is unknown as to whether the circulation was on the ground producing a tornado at this time. Image: Brad Hannon, taken from Hume Highway looking south-east near the Clonbinane turnoff.

Figure 10: With the environment depleted by the earlier storms, a striated supercell occurred over Melbourne at sunset. The striations indicate the rotating layers of inflow into the storm, and are a result of the contrast between moist air within the storm and dry environmental air. Image: Brad Hannon, taken near Wandong looking south. author. A video of the event will appear on a DVD from significant challenge from an operational warning and the ‘Hunters of Thunder’ (www.huntersofthunder.com) in forecasting standpoint. the near future.

This storm event highlights the difficulty of disseminating severe thunderstorm warnings on public holidays such References: as Christmas. The traditions of the day meant that many Davies-Jones, R., Trapp, R.J., and Bluestein, H.B., 2001. people were unlikely to be paying attention to the internet, Chapter 5: Tornadoes and Tornadic Storms. Severe radio or TV sources or even the weather outside. Th is Convective Storms, Meteorological Monographs, dramatically enhanced the risk of exposure to the impacts American Meteorological Society, Boston, USA, 167–221. of the severe thunderstorms and likely resulted in more vehicles being damaged by hail than would ordinarily Doswell III, C.A. and Burgess, D.W., 1993. Tornadoes be the case. Th is lack of public awareness also had a and Tornadic Storms: A Review of Conceptual Models. substantial impact on the availability of real time reports The Tornado: Its Structure, Dynamics, Prediction, and of severe phenomena including the hail and tornadoes Hazards, Geophysica, 161–172. that added difficulty to the warning process. The Bureau Doswell III, C., 2001. Chapter 1: Severe convective storms of Meteorology did an impressive job in responding to a – An Overview. Severe convective storms, Meteorological difficult warning situation and dealing with an unusual Monographs, American Meteorological Society, Boston, type of severe thunderstorm outbreak and should be USA, 1-26. commended for issuing prompt and accurate warnings.

The inclusion of tornado warnings does raise questions Forbes, G.S., 1981. On the reliability of hook echoes as about the public perception of tornadic events, which tornado indicators. Monthly Weather Review, 109, 1457requires further examination. It is also questionable 1466. whether there is the capacity for the public to respond to the Galway, J.G., 1956. The lifted index as a predictor of threat when presented with such warnings. It is difficult to latent instability. Bulletin of the American Meteorological see the threat being taken seriously while there continues Society, 43, 528-529. to be the myth that somehow tornadoes experienced in Australia (usually referred to as mini-tornadoes by the Harper, B., Granger, K., and Hall, S., 2000. Chapter 6 : media, e.g. http://www.abc.net.au/news/2012-05-06/miniSevere Thunderstorm Risks. Natural Hazards and the tornado-destroys-abrolhos-shacks/3993958) are always less Risks they Pose to South-East Queensland, 11pp. intense than their United States counterparts. It remains a Holton, J.R., 2004. An Introduction to Dynamic fact that when (not if) a strong tornado impacts a major Meteorology. Academic Press, New York. 535 pp.

Australian city that the potential for injuries and causalities will be high owing to the general populations’ lack of Moller, A. R., Doswell III, C.A., and Przybylinski, R., awareness of the threat and the weakness of Australian 1990: High-Precipitation supercells: A conceptual model building standards to tornadic winds (Harper et al. 2001). and documentation. Preprints, 16th Conference on Severe Local Storms, Kananaskis Park, Alta., Canada, American Acknowledgements Meteorological Society, 52-57.

The author would like to thank the Bureau of Meteorology Weisman, M., and Klemp, J., 1982. Dependence of for the synoptic charts, rawinsonde observations and radar numerically simulated storms on vertical wind shear and data used in this article. The author would also like to thank buoyancy. Monthly Weather Review, 110, 504–520.

Brad Hannon for the photos and first hand observations from the event that greatly contributed to the overall Yeo, S., Leigh, R. and Kuhnel, I., 1999. The April 1999 synopsis. Further photographic and video documentation Sydney Hailstorm. Australian Journal of Emergency of this event is available from Brad via contacting the Management, 14, 23–25.

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 51

Meet a Member

Janine Yuasa Where does this find you?

It is currently 1 a.m. and I am halfway through a night shift.

What do you do?

I am a forecaster in the Brisbane Regional Forecasting Centre of the Bureau of Meteorology. From this office, my colleagues and I issue the forecasts for the general public and aviation industry in central, western and southern Queensland; we also issue marine forecasts for the entire Queensland coastline and the Coral Sea for shipping purposes. Our colleagues in our Cairns and Townsville offices issue forecasts for northern Queensland. We also issue the all important warnings for phenomena like severe thunderstorms, tropical cyclones and significant wind strengths, as well as various aviation warnings for things like severe turbulence.

Of course the weather does not conveniently stop overnight, so night shifts come as part of the job.

Why did you get into it?

As a child, I had always been fascinated by and had a healthy respect for the awesome power and beauty of thunderstorms (after getting over the scary factor). As a teenager in year 10, I distinctly remember looking out the window at what I would later learn was a cumulus cloud and wondering, “How do clouds form? What turns such innocuous looking clouds into raging thunderstorms?” At the time I was more interested in a career as a veterinarian, but by the time I reached the end of high school I was certain I wanted to follow a career in meteorology as I realised I did not want to be directly responsible for a living creature’s life (or death), and its owner’s resultant emotions.

What is the best thing about what you do?

There are a fair few, but if I had to pick one it would be the fact that it’s a fairly unusual but useful job that means we’re masters at the weather small talk (which can sometimes

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 52

Queensland member Janine Yuasa turn into a fully fl edged topic of conversation if the audience is sufficiently interested). Also, it’s a great feeling knowing that in some way or another I am helping people to make decisions in their day to day life. Whether it be helping the average person decide whether or not they need an umbrella, or helping a pilot decide whether or not they should take that flight out to outback Queensland.

How do you relax?

I like to relax by doing a lot of catching up: on missed sleep, on the TV shows or movies I missed during my run of shifts, or catching up with friends if they’re available on my days off. A good absorbing book doesn’t go astray either.

What is your favourite holiday destination?

I have only travelled to Japan and around parts of Australia (so far) but I would have to say tropical north Queensland is a beautiful part of the world. I was actually there for work but did drive around the area on days off to explore the numerous stunning waterfalls, pristine rainforests and sparkling beaches. Unfortunately, I didn’t get around to exploring the Great Barrier Reef, so it’s definitely a destination I will be revisiting.

Snapshot

Cumulonimbus at sunset over the Coral Sea 29 April 2012 Jennifer Catto

This photogenic cumulonimbus cloud was photographed at approximately 6 p.m. AEST over the southern Coral Sea on a flight from New Caledonia to Brisbane. Storms such as these can be a hazard for aircraft; however, by avoiding this storm the pilots gave the photographer the chance to

capture the anvil and the overshooting top in the fading evening light.

If you have an image of the weather near you to share, send it to duncan.ackerley@monash.edu, or post it on the AMOS Facebook page. — Ed.

Are you a postgrad student enrolled at a university in NSW? Do you work in an area related to meteorology, oceanography or the climate?

AMOS and the ARC Centre of Excellence for Climate System Science bring you the

2012 AMOS NSW Centre Postgraduate Student Symposium

Friday 20 July 2012, 09:00 – 17:30 at the

Climate Change Research Centre, Level 4, Mathews Building, Kensington Campus,

University of New South Wales, Sydney

This event will give postgrad students working in meteorology, oceanography or the climate the opportunity to share their research with other students

and hone their presentation skills in a presenter-­friendly environment. Students will also pick up tips and advice that they may find useful in their studies

th

and future careers from Prof Andy Pitman, Director of the ARC Centre of Excellence for Climate System Science and Dr Sarah Perkins, a postdoc at the University of New South Wales. The program for the day will include talks by Andy and Sarah, 15 or 20 minute talks by student attendees and free lunch and morning and afternoon tea, kindly sponsored by the ARC Centre of Excellence for Climate System Science. A prize will be awarded for the best student presentation.

Space and student speaking slots at the symposium are limited and will be allocated on a first-­come-­first-­served basis , so get in quick!

If you wish to attend the event, please RSVP to Andrew King (andrew.king@student.unsw.edu.au), by Friday 29th June indicating:

1) Whether you wish to give a talk at the event or not and, if you do, the title of your talk.

2) Whether you have any special dietary requirements.

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 53

Charts from the Past with Blair Trewin

18 July 1917 One of the most intense La Niña events on record occurred during 1916 and 1917, with the Southern Oscillation Index reaching record levels. The impact on Australian rainfall during the 1916-17 northern wet season was considerable, with heavy falls throughout most of the country; it was widely the wettest such period between 1900 and 1970, although falling short of 1973-74 and 2010-11. The most extreme impacts, though, were on temperature. 1916-17 was the coolest summer on record for Australia, 1917 the coolest autumn, and February 1917 had the largest negative mean temperature anomalies of any month in Australian history. Every month from October 1916 to June 1917 had a national anomaly of −1.4°C or lower.

Rainfall returned to normal throughout much of Australia during the cooler months of 1917, but the southern fringe of the continent was an exception, with persistent aboveaverage falls, particularly in the southwest. 1917 went on to be the wettest year on record for the south-west of Western Australia and for south coastal Australia in general, while new benchmarks were set for highest annual rainfall in both South Australia and Western Australia. (The South Australian record still stands; the Western Australian one was broken in 2000).

One of the more dramatic events of this winter came in mid-July. Initially a front, one of a long succession, crossed Western Australia on 16 July. Rainfall from this individual system was not extreme (the highest daily total was 49 mm at Cottesloe), but it came near the end of a very wet period (Perth had rain on 35 of 37 days from 18 June to 24 July), with severe flooding a consequence. The Moore and Avon valleys were especially hard-hit: many properties were inundated in Northam and York, while Moora was isolated for a week. The Swan Valley also saw extensive floods. Three people were killed in a rail crash on the flood-damaged Perth-Geraldton line.

On 18 July a low intensified on the system to the south of South Australia. Pressures were exceptionally low, including 979 hPa at Cape Northumberland and 989 hPa at Adelaide. Rainfall was heavy, although quite localised to the Flinders Ranges and the Adelaide region. Wilpena received 88 mm on 18 July, and numerous Adelaide Hills stations had 60 to 75 mm on 19 July, although in most other parts of southern South Australia falls were 10 mm or less. The strong pressure gradient on the low resulted in high winds (84 km hr-1 at Adelaide, and stronger on the coast), and a major storm surge on the coast.

Flooding in the Adelaide region was severe and widespread, being reported as the worst on record at that time, with the Torrens, Gawler, Light and Para rivers all affected. Many houses were flooded between Torrensville and Fulham, and bridges were damaged by heavy debris carried through the city. Further downstream (a market garden area in 1917), there was major fl ood damage to fruit and vegetable crops. The storm surge and winds were also destructive on the coast. The public baths were destroyed at Semaphore as were more than twenty bathing sheds at Henley Beach, while there was also major damage to numerous piers and the Glenelg breakwater, which was under construction at the time. Only minor wind damage was reported in the central city.

The system moved rapidly eastwards and weakened, being east of Tasmania by the evening of 19 July. Rainfall measurements above 20 mm were mostly confined to western Tasmania and the Victorian and southern NSW ranges. The latter falls, on wet ground, caused some flooding in the upper Murray catchments (although worse had occurred in June, and was to do so again during October in one of the Murray’s most notable flood years).

Synoptic chart for 2100 AEST, 18 July 1917

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 54

Calendar

2012

October

July 8–13 20th Symposium on Boundary Layers and Turbulence and 18th Conference on Air-Sea Interaction, Boston, USA. 9–13 12th International Coral Reef Symposium, Cairns.

9–13 ARC Centre of Excellence for Climate System Science’s fi rst winter school, School of Earth Sciences, Melbourne University, Melbourne.

13–25 XXXII Scientific Committee on Antarctic Research and Open Science Conference, Portland, USA. 20 AMOS and the ARC Centre of Excellence for Climate System Science 2012 AMOS NSW Centre Postgraduate Student Symposium, University of New South Wales, Sydney.

8–12 AGU Chapman Conference on The Agulhas System and its Role in Changing Ocean Circulation, Climate, and Marine Ecosystems, Spier Hotel, Stellenbosch, Western Cape, South Africa.

22–25 NOAA’s 37th Climate Diagnostics and Prediction Workshop, Colorado, USA.

November 5–8 AMS 26th Conference on Severe Local Storms, 5–8 November 2012, Nashville, Tennessee, USA.

December 3–4 Annual International Conference on Geological & Earth Sciences (GEOS 2012), Hotel Fort Canning, Singapore.

30–3 August 16th International Conference on Cloud and Precipitation, Leipzig, Germany.

3–7 AGU 2012 Fall Meeting, San Francisco, California, USA.

30–10 August European Space Agency Earth Observation Summer School on Earth System Monitoring and Modelling, Italy.

2013

August 13–17 AOGS–AGU (WPGM) Joint Assembly, Sentosa Singapore.

20–24 15 Conference on Mountain Meteorology, Colorado, USA. th

February 11–13 19th Annual AMOS Conference, Melbourne.

April 7–12 EGU General Assembly 2013, Vienna, Austria.

26–30 32nd International Geographic Congress, Cologne, Germany.

Australian Meteorological and Oceanographic Journal

Articles — Vol 62 No. 1, March 2012 Courtney et al. Documentation and verification of the world extreme wind gust record.

Larsen and Nicholls. The nature of the recent rainfall decrease in the vicinity of Melbourne, southeastern Australia, and its impact on soil water balance and groundwater recharge.

Radhi et al. Biomass-burning aerosol over northern Australia.

Shaik and Lisonbee. The tropical circulation in the Australian/Asian region - November 2010 to April 2011.

Bulletin of the Australian Meteorological and Oceanographic Society Vol.25 page 55

Regular Features: Tobin and Skinner. Seasonal climate summary southern hemisphere (autumn 2011): one of the strongest La Nina events on record begins to decline.

Wu. Quarterly numerical weather prediction model performance summary — October to December 2011.

2012 AMOS Council Executive

President Vice-President Secretary Treasurer Past President

Blair Trewin Todd Lane Damien Irving Ian Watterson Neville Nicholls

Ordinary Members John Allen Andrew Klekociuk Robin Roberston Sandra Schuster Richard Wardle Perry Wiles

03-8344 9596 03 6232 3382 02-6268 8289 02-9272 8025 03-9905 4411 03-9669 4664

AMOS Administrative Officer

Jeanette Dargaville GPO Box 1289, Melbourne VIC 3001 (attn: AMOS admin officer) Phone 0404 471 143 E-mail: admin_officer@amos.org.au

03-9669 4623 03-8344-6516 03-9239 4685 03-9239 4544 03-9902 0111

Sub-Committee Convenors Public Relations Awards 2013 Conference Education Membership

Centre Chairs NSW Hobart Melbourne ACT Perth Darwin Brisbane Adelaide

Vacant Mark Williams Vaughan Barras Phillip Riley Michael Hewson

0419 519 440 03-9669 4045 03-9669 4530 0408 379 373

Steven Phipps Kelvin Michael Damien Irving Clem Davis Merv Lynch Hakeem Shaik Hamish McGowan Andrew MacKinnon

02-9385 8957 03-6226 2977 03-9239 4685 02-6254 2861 08-9266 7540 08-8920 3814 07-3365 6651 08-8313 3875

Representatives AMOJ Science & Technology Australia

David Karoly

03 8344 4698

Steven Phipps

02-9385 8957

AMOS is represented on the relevant Australian Academy of Science committees..

2012 Bulletin of the Australian Meteorological and Oceanographic Society ISSN 1035-6576

Editor

Duncan Ackerley Monash Weather and Climate School of Mathematical Sciences Monash University VIC 3800 Phone: 03-9902 4900 Fax: 03-9005 4403 Email:duncan.ackerley@monash.edu

Editor-in-chief

Stewart Allen Email: Stewart.Allen@bom.gov.au

Assistant Editors Diana Greenslade Blair Trewin Linden Ashcroft

Regional Sub-editors

Michael Hewson (Brisbane) Caecilia Ewenz (Adelaide) Nicholas Tyrrell and Luke Hande (Melbourne) Fiona Johnson (NSW) Clem Davis (ACT)

Contributors Blair Trewin

Advertising Manager Please contact the Admin. Officer.

Publisher

AMOS, GPO Box 1289, Melbourne VIC 3001, Australia

Contributed articles, news, announcements and correspondence for the Bulletin should be sent to the editor no later than 20 July 2012. They will be reviewed and the galley proofs returned to the author if requested. An ASCII version of the text is required via e-mail or digital media to minimise typographic errors.

The Bulletin of the Australian Meteorological and Oceanographic Society is produced and distributed with the assistance of CSIRO Marine and Atmospheric Research and the Bureau of Meteorology.

AMOS Website: www.amos.org.au