Bulletin vol 27 no 1 26th feb 2014

AMOS

AustralianMeteorological & OceanographicSociety

Bulletin of the Australian Meteorological & Oceanographic Society Vol 27, No.1, February 2014 ISSN 1035-6576

Contents Editorial ............................................................................................................................................................................1 President’s Column ..........................................................................................................................................................1 News ................................................................................................................................................................................2 News from the Centres ....................................................................................................................................................5 Conference report ............................................................................................................................................................6 Article ...............................................................................................................................................................................7 Annual Australian Climate Statement 2013 ............................................................................................................................. 7

Meet a Member .............................................................................................................................................................13 Snapshot ........................................................................................................................................................................14 Charts from the Past with Blair Trewin: 6 January 1994...............................................................................................15 The Research Corner with Damien Irving......................................................................................................................16

ISSN 1035-6576 Cover picture: “Mountainous coulisses with hazy veils“. 170-km-line-of-sight across Watzmann to Wetterstein (Zugspitze) from an airliner above Hallein, Austria, October 2007 (more details under http://imaggeo.egu.eu/view/1540/ ).

Image: Hans Volkert.

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

World Meteorological Day 2014 “World Meteorological Day” falls on 23 March each year and is an event that celebrates the 1950 convention, which led to the formation of the World Meteorological Organization (WMO). This is an important day in the calendar where we should consider the achievements in Meteorological (and Oceanographic!) science, especially over the last 64 years since its inception. As described in Zillman (2013), in the case of the World Weather Watch, the WMO has been at the forefront of international scientific co-operation in meteorology (and also operational hydrology and related geophysical sciences) and a great success story in our field.

The focus of World Meteorological Day this year is, “Weather and Climate: engaging youth”. The WMO makes the point that : “Today’s youth will benefit from the dramatic advances being made in our ability to understand and forecast the Earth’s weather and climate. At the same time, most of them will live into the second half of this century and experience the increasing impacts of global warming,“ which highlights the importance of guiding and developing younger scientists within our community.

Other information and resources can be found on the WMO website1.

It is great to see the WMO making a specific point about encouraging younger scientists, as it is something I have been trying to do with BAMOS. For example, I have invited the award winners at various conferences and AMOS student symposia to submit their work to BAMOS. As BAMOS provides a potentially “less hostile” route to producing a peer-reviewed article, it is a great place for our younger scientists to submit their work. It is something that I will try to encourage, even after leaving the Editor role, as I remember how intimidating the reviews from my first few papers seemed to be. It would also be great to get the support of supervisors (Ph.D., M.Sc. and Honours) in doing this and that will be another 1

http://www.wmo.int/worldmetday/index_en.html

aim of mine in the future. I feel very strongly that articles from students should be an integral part of maintaining BAMOS as an interesting, informative and scientifically relevant magazine.

Something else I’d like to draw attention to is another scheme designed to help encourage and develop young scientists. The Australian Research Council Centre of Excellence for Climate System Science has been granting summer research scholarships to undergraduate students.

The scheme provides paid research positions for six to eight weeks over the summer and gives students supervised research experience. I jointly supervised one of these students at Monash University, which produced some very interesting results (and worthy of publication if written up). The student enjoyed the topic and approached the position as a way to gain research experience in order to help decide his future career. Such experiences are therefore very important in encouraging prospective scientists and the Centre of Excellence should be congratulated for developing this scheme. I will certainly volunteer to do another one next year (and would encourage others to do so) to help further the World Meteorological Day initiative.

Finally, I would like to mention the recent AMOS conference. Having been present at the AMOS committee meetings from the initial decision to hold the conference in Hobart, I have seen the hard work that has been put in by the Conference organising committee. I would personally like to congratulate them on all the fantastic effort they have put in, which resulted in the 2014 Conference being another amazing AMOS event that I very much enjoyed attending.

Reference Zillman, J.W., 2013. Fifty years of World Weather Watch: Origin, implementation, achievement, challenge, Bulletin of the Australian Meteorological and Oceanographic Society, 26, 121–135.

Duncan Ackerley

President’s Column

Final reflections as President of AMOS As I write my final column as President before handing over to Todd Lane at the AGM at the upcoming Hobart Conference, it is a good time to reflect both on the state of AMOS as an organisation, and on the health of the profession in general.

Thanks to the hard work of a lot of people over several years, AMOS has made great strides in its governance in recent times. We now have an organisation on a sound Bulletin of the Australian Meteorological and Oceanographic Society Vol. 27 page 1

financial footing and effective administrative structures— something which isn’t necessarily visible to the bulk of the membership but is essential for the organisation to continue to run smoothly. A lot of the groundwork for this was laid during Neville Nicholls’ presidency; over the last two years we have been able to build on this, and now have our first strategic plan as an organisation, which has given us the opportunity to think about (and solicit our

members’ views on) what the most important things are for AMOS to be doing.

We have seen growth in our membership, which has recently hit 600 for the first time, and very strong growth in attendance at our conferences, with over 400 attending last year’s Melbourne conference. We did not quite get that many to Hobart, but the numbers there were still well in excess of most AMOS conferences before 2010. This growth is a good indicator of the organisation’s increasing strength in itself, but it also gives us the financial resources to achieve more of what we would like to achieve.

I also feel generally optimistic about the overall state of the profession. There may still be some turbulent political waters to be navigated, but so far the war on climate science has mostly stayed where it’s been for several years, in certain corners of the blogosphere and the airwaves and the opinion pages of various newspapers. I’m particularly excited by a lot of the activity happening in the university sector—which, in our fields, was struggling badly ten or fifteen years ago—and the number of good, young scientists coming through.

Having good-quality professionals in our field in Australia is one thing, from doing the operational work associated with the many extreme events we have seen in recent years, to being at the cutting edge of research.

Having the infrastructure to support them is another thing. Observations are the lifeblood of our science, and they depend on a great deal of well-coordinated work both nationally and internationally. The rapid, recent decline of the Tropical Atmosphere Ocean array of ocean observations, critical to the monitoring and prediction

of El Niño and La Niña events, as a result of budgetary wrangling in the United States is a stark reminder of just how dependent our science is on a wide range of observations, many of them funded and supported beyond our shores.

As a scientist, something which I have a commitment to beyond almost anything else is informing factbased public policy. Sometimes in recent years one has wondered whether the saying that “you are entitled to your own opinion but not to your own facts” (attributed, I believe, to an American Senator of the 1980s) still applies, but at the end of the day the best we can do is to get facts out there. Facts are the greatest weapons we have in the contest against ignorance, and while there are those who will never accept what we have to say, at the end of the day those people are a small minority of the community and we should not let their influence outstrip their numbers.

Communication is an important part of promoting factbased public policy, and we plan for it to become an increasing focus of AMOS in the years to come.

I would like to finish by thanking everyone who has contributed to the success of AMOS over the last two years.

In particular, I would like to thank our Executive Officer, Jeanette Dargaville, who has performed well above and beyond the call of duty. I am not sure how we would have kept functioning without her. I would also like to thank my fellow Executive members, Todd Lane, Damien Irving and Ian Watterson, for their work, and wish Todd, in his role as President-elect, and the rest of the new Executive the best of luck over the next two years.

Blair Trewin

News

Bio robots make a splash in the Indian Ocean Nicholas Kachel

CSIRO, Communications Advisor, Wealth from Oceans Flagship.

Email: csiromedia@csiro.au The Indian Ocean contains vast fisheries and mineral resources that are of strategic importance to both Australia and India. It also plays a direct role in driving the climates of its surrounding regions and is home to more than 16% of the world’s population.

The new ‘Bio Argo’ floats, to be launched in mid-2014, will enhance the already successful Argo float technology to measure large-scale changes in the chemistry and biology of marine ecosystems below the Indian Ocean’s surface.

The Argo floats are a network of 3600 free-floating sensors, operating in open ocean areas that provide real-time data on ocean temperature and salinity.

The ‘Bio Argo’ floats will include additional sensors for dissolved oxygen, nitrate, chlorophyll, dissolved organic matter, and particle scattering. They will target specific gaps in our understanding of Indian Ocean ecosystems of Bulletin of the Australian Meteorological and Oceanographic Society Vol. 27 page 2

immediate concern to India and Australia, such as the Bay of Bengal and the waters off northern Western Australia.

CSIRO’s Dr Nick Hardman-Mountford said the pilot project, led by CSIRO in collaboration with the Indian Council of Scientific and Industrial Research–National Institute of Oceanography (CSIR-NIO) and the Indian National Centre for Ocean Information Services, will improve our understanding of cause and effect in the Indian Ocean’s climate and ecosystems.

“By studying the Indian Ocean in this detail, we can investigate the origin and impact of marine heatwaves— like the one that devastated the coral reefs and fisheries off northern Western Australian in 2011—and improve our prediction of them in the future,” Dr Hardman-Mountford said.

CSIR-NIO Director, Dr Wajih Naqvi, said the novel technological innovation will give researchers from both countries a new understanding of the Indian Ocean.

“We expect the technology being utilised in this project to provide new insights into the biogeochemistry of the Indian Ocean and how it is being impacted by human activities,” Dr Naqvi said.

The proposed advances in ocean observation, ecosystem understanding and resources management, which will benefit the entire Indian Ocean Rim, can only occur through collaboration between India and Australia.

Dr Nick D’Adamo, Head of the Perth Programme Office supporting UNESCO’s Intergovernmental Oceanographic Commission (IOC)—a partner in the project—praised the collaborative nature of the project.

“By combining the research capabilities of India and Australia we will see an improved ability to predict and prepare for global climate change, as well as better conservation of marine biodiversity,” Dr D’Adamo said.

The $1 million project was funded in part by the Australian Government under the Australia-India Strategic Research Fund.

The Priestley Cup 2013 Frank Drost, Meelis Zidikheri and Andrew Watkins Bureau of Meteorology, Melbourne, Victoria

The Priestley Cup, the annual AMOS soccer tournament between Monash University, Melbourne University, CSIRO and the Bureau of Meteorology (BoM) was held on Friday 6 December 2013 at the sportsground of Melbourne University. While in the last three years this tournament was held indoors, this year we returned it to an outdoor event. The day prior to the tournament saw Melbourne having one of its coldest days in December and showery weather with 7 mm of rainfall. Luckily all that “bad” weather was gone at kick off time on Friday and the players were basking in warm, sunny weather.

Besides returning the tournament to the outdoor fields again, the AMOS Melbourne Committee had made some changes to the rules of the tournament with the aim to increase the social aspect of this gathering. It was felt that the winning mentality was becoming too strong at the expense of the social aspect of the tournament. Each team had to have two women on the court at all time and cards were introduced for fouls. Whether it was the introduction of these rules, the nice summer weather or the promise of lots of pizzas and drinks afterwards, a very social and joyful day was had by everyone.

As the matches were played on two fields, below is a short overview of the matches on court 1 and court 2.

Court 1 In the first round of the round-robin tournament, Monash played Melbourne, and BoM played CSIRO. The game between the Universities saw a lot of very keen players, lots of running and hard work, but only one team being successful in scoring. Once ahead, Monash never looked like relinquishing their advantage and they won in the end comfortably: 3-0.

In the second round CSIRO played Monash and BoM played Melbourne. The match between CSIRO and Monash was an even one and not much was in it. For a while it looked like Monash University was going to take the win with their first half goal, but with less than 2 minutes left on the clock CSIRO equalised. The final result was 1-1.

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The final round-robin match on court 1 was between CSIRO and Melbourne. The CSIRO team had a theoretical chance of winning the tournament if they beat Melbourne by four goals and the match between BoM and Monash were to end in a draw. At the same time, Melbourne had to win to avoid the wooden spoon. But it was evident that the weather was going to play its part in the end after all. After having already played two matches, the sun shining brightly and temperatures creeping up, neither team seemed to have enough energy left to really bother the opposition. There were some opportunistic shots and some saves from the goalies, but the only goal, which was indeed very well taken, came from a scramble in front of the goal. It was Melbourne who scored the only goal and with that passed on the wooden spoon to the previous Priestley Cup holders (CSIRO).

The Priestley Cup winner was subsequently decided on court 2.

Court 2 Confidence in the BoM ranks was actually not too high coming in to the Priestley Cup this year, mainly because we didn’t have many opportunities to practise prior to the tournament due to the lack of good playing grounds around Docklands. It was also unfortunate that the tournament was being held on the same day as our BoM head office Christmas party, so a few potential players opted for the band and beers instead of the backline and ball.

That said, we were determined to do our best and started our first game against CSIRO knowing that a strong defence would be the key to getting a good result. The team showed tremendous spirit and discipline to keep CSIRO and their star striker at bay for a morale-boosting 0-0 result. Clean sheet 1 to goalie Simon Grainger.

Encouraged by this result we decided to build on our solid defence and take advantage of set-pieces to find a goal against Melbourne University, our next opponents, who with their skilful and coordinated attacks stretched our defence to the limit and would have scored if not for a combination of good goalkeeping from Simon, dogged

The 2013 Priestley Cup winners—The Bureau of Meteorology. Image: Yuelong Miao. defending, and, let’s face it, a bit of the good old lady luck.

At the other end, our tactics paid off and we managed to scramble in a goal before another attack resulted in an unfortunate Melbourne University player putting the ball in his own net. With a 2-0 win (clean sheet number two to Simon), we knew that to win the tournament a win was required against our final opponents, Monash University, who only needed to draw because of earlier excellent results. (That said, team statistician and AMOS president Blair Trewin did point out that a 4 goal win by CSIRO would give them the tournament if our game was drawn.)

The team showed tremendous composure and discipline to keep the score 0-0 at halftime. We then had to make a decision whether to continue playing defensively in the second half or to take the risk and commit more players forward. Ultimately, it was decided that we should go for it, and it turned out to be a good decision, for we managed to put more pressure on the opposition’s defence and in one of those moves Jing-Jia Luo put the ball in the net from what looked like an impossible angle.

From then on, it was a matter of holding on at all costs and we reverted to our defensive set-up as Monash University pressed hard for a tournament-winning equaliser. For a moment Monash thought they had it, only for the goal to be disallowed as it came from a direct kick off the sideline, which was not allowed. (And hats off to Prof. David Karoly, ex-Monash University winning “Priestley-Cupper” and final game referee; he certainly knew the rules and when

to apply them.) Final whistle: 1-0 to the BoM. Clean sheet 3 to Simon.

Overall, it was a tremendous performance from the BoM team who showed unbelievable spirit and discipline, not to mention some degree of skill, to get the results that won us the tournament. Well done also to Simon, with one of the few ever Priestley Cup goalie clean sheets. We also have to thank the supporters—the Bureau appeared to be the only team with a cheer squad consisting of almost solely under-5s—plus their carers, who successfully averted any mass kiddie pitch invasion mid-game when they spotted their mum or dad with the ball!

Finally, thank you to the two refs (David Karoly and Frank Drost) and the three other teams for the exemplary sprit in which the competition was played. Yet again everyone went out and had good clean competitive fun, then shared a well-earned pizza and stories—as well as comparing astroturf burns—at Melbourne University’s Earth Sciences department afterwards. Thanks also go out to the AMOS Melbourne Committee who organised the Priestley Cup event and then in particular Damien Irving who organised the venue and Katherine Sadler for looking after the hungry and thirsty players afterwards. See you all (and hopefully a few more soccer newbies) again next year.

Go the Reds!

International Association of Meteorology and Atmospheric Sciences (IAMAS) News Tom Beer

National IAMAS Correspondant

1st World Weather Open Science Conference, 16–21 August, Montreal The 1st World Weather Open Science Conference, 16–21 August in Montréal, will be an important basis for the next 50 years of international cooperation in meteorology.

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Future Earth Diana Greenslade, one of the Assistant Editors of BAMOS, is currently in Paris working with the International Council of Science (ICSU) on the new “Future Earth1” initiative.

1

www.futureearth.info/

The IAMAS Executive passed a resolution in recognition of the establishment of Future Earth at the IAMAS meeting held in Davos in July 2013. The resolution2, is as follows:

Welcomes: t

Recognising: t

the major sustainability and environmental challenges currently confronting the scientific community and the nations of the world;

t

the centrality and significance of atmospheric processes to the determination of the weather, air and water quality, the frequency and intensity of floods and droughts, and both short-term climate variability and long-term climate change;

t

that a well-founded understanding of the Earth system is built on a base of on-going and high quality surface, in situ, ship, aircraft, and space-based observations, intensive studies of processes and interactions, a hierarchy of models capable of representing the wide breadth of space and time scales, and the analysis of a strong scientific community; and

Urges: t

the atmospheric sciences community and its various components to engage fully with the new activity; and

t

the leadership of the “Future Earth” to sustain, draw upon and build the community’s expertise for addressing the many important societal, environmental and other challenges facing the world community; and

Recommends: t

the continuation, evolution and expansion of the research encompassed in the IGBP and other relevant projects, including the facilitation, direction and orientation of field campaigns, and the provision and preservation of long-term data sets that yield the evidence base for determining key atmospheric and surface parameters required by policymakers;

t

the initiation, development, and sustenance of cooperative partnerships between the International Union Geodesy and Geophysics and its Associations and “Future Earth” for the purpose of ensuring and strengthening the programs of research, analysis, and observations needed to advance scientific understanding of the Earth system and meet the many, diverse needs of “Future Earth”; and

t

the devotion of special attention to education, training, and mentoring in areas that will build and expand the intellectual capacity of the natural and social sciences, especially focused on providing development, participation, and recognition of those who can provide expertise for bringing advances in understanding across disciplinary areas.

Valuing: t

the observations being gathered by nationally and internationally supported satellite, surface, and in situ-based systems and networks;

t

the important insights and understanding emerging from the major research projects and their coordination efforts organised particularly by the International Geosphere-Biosphere Programme (IGBP) and the World Climate Research Programme (WCRP) since their inception;

t

the advanced modelling and research programs being supported in many nations, including particularly the essential computational, analytic, and data storage resources provided to ensure the success of these efforts; and

t

the promotion of international cooperation in science by the nations of the world in order to most rapidly advance scientific understanding;

the establishment of “Future Earth” by the ICSU in cooperation with the Science and Technology Alliance for Global Sustainability; and

2www.iamas.org/Pdfs/IAMAS-Resolution_FutureEarth-2013.pdf

News from the Centres

ACT Centre News Clem Davis

Immediate Past President, ACT Centre The ACT AMOS branch held its AGM in early December along with a student presentation night.

The new committee is: President: Bob Cechet Secretary: Jason Sharples Committee: Patrick DeDeckker, Clem Davis, Jay Larson, Nick Engerer, Jeff Kingwell, Mona Brahi Bulletin of the Australian Meteorological and Oceanographic Society Vol. 27 page 5

Student Prize Winners for 2013 AMOS Prize: Jack Muir (ANU) ACT AMOS Prize: Hamish Wallace (UNSW, ACT campus) ACT Student presentation prize: Craig McConniche (ANU, RSES)

Meetings Branch Meetings for 2014 to be all held at CSIRO Discovery Centre 5–7 p.m. 20 March: The IPCC Report and Australia.

12.30–4 p.m. 17 August (National Science Week): Climate impacts on human health and society 5-7 pm September 18th: Climate change and agriculture Further details available online as we finalise our speakers.

Speakers: Professor Will Steffen and Perry Wiles.

5–7 p.m. 22 May: Oceanography modelling and applications.

5–7 p.m. 24 July: Antarctica: What is happening with its climate?

A year ten high school student has done a study of temperature over different surfaces around his school (Melrose High School). The report is to be submitted to BAMOS for consideration for publication. He went and built his own mini-Stevenson screens for the project.

Conference report

2013 AMOS NSW Centre Postgraduate Student Symposium 29 November 2013, University of New South Wales, Sydney Carly Tozer Environmental and Climate Change Research Group, University of Newcastle

It was an early start for four University of Newcastle postgraduate students on the last Friday of November 2013. Bleary eyed, we piled into the car on the way to the University of New South Wales (UNSW), Sydney, for the AMOS NSW Postgraduate Symposium. Starting in 2011, the Symposium has become an annual event where students across NSW and the ACT are invited to present their work in a relaxed, friendly environment and to hear about the experiences of distinguished academics that were once in our shoes.

The day commenced with an ice-breaker activity where we learnt some interesting facts about our peers—from appearing on Zambian TV twice, to knowing three languages, to not being on Facebook (heaven forbid!). We then moved onto the student presentations; throughout the day we heard eleven presentations on topics including paleoclimate reconstructions, seasonal rainfall variability, climate extremes, land-atmosphere coupling, climatic hiatus periods and the relationship between weather and health. Along with being entertaining and informative, the presentations revealed the depth and diversity of research being undertaken by postgrads within the climate field in NSW and the ACT.

“Publish, publish, publish!” was definitely a theme of the day. Key points about paper writing included: writing like the papers that are already published and keeping it simple, interesting and focused.

The day ended with some drinks and snacks and relaxed conversation between the attendees. Who doesn’t like to finish the day with a cold Coopers Pale Ale? Thanks to the ARC Centre of Excellence for Climate System Science for sponsoring the day and to Andrew King and Nicola Maher for organising the event. Congratulations to Michelle Ho from the University of Newcastle whose presentation was voted the best of the day.

Between the student presentations we listened to and asked questions of a postdoctoral panel featuring Dr Jatin Kala, Dr Leela Frankcombe and Dr Markus Donat, all postdocs at UNSW. They spoke about their experiences undertaking and completing their Ph.Ds and how they went about getting their postdoc positions. Key advice from the panel discussion was to publish as you go, network at conferences and in regards to postdoc positions—just apply anyway even if the topic seems out of your field.

A highlight of the day was the presentation given by Prof.

Andy Pitman, Director of the Australian Research Council (ARC) Centre of Excellence for Climate System Science.

He spoke about how at this stage our core business is having a thesis that passes, good referees and publications.

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Postdocs Leela Frankcombe, Markus Donat and Jatin Kala give tips to students during a Q&A session. Image: Nicola Maher

Article

Annual Australian Climate Statement 2013 National Climate Centre, Bureau of Meteorology Data collected and analysed by the Bureau of Meteorology show that 2013 was Australia’s warmest year on record while rainfall was slightly below average nationally. t

Summer 2012–13 was the warmest on record nationally, spring was also the warmest on record and winter the third warmest

t

Overall, 2013 was Australia’s warmest year on record: annual national mean temperature was +1.20°C above average

t

All States and the Northern Territory ranked in the four warmest years on record

t

Nationally-averaged rainfall was slightly below average for the year, with 428 mm (1961–1990 average 465 mm)

t

Rainfall was mostly below average for the inland east and centre, and above average for the east coast, northern Tasmania and parts of Western Australia

The original statement issued by the Bureau was compiled from data available on 2 January 2014. Some minor updates have been made using additional data which have become available since then. There may be further minor changes to final values as a result of subsequent quality control and the availability of additional data..

Overview 2013 was Australia’s warmest year since records began in 1910. Mean temperatures across Australia have generally been well above average since September 2012. Long periods of warmer-than-average days have been common,

with a distinct lack of cold weather. Nights have also been warmer than average, but less so than days.

The Australian area-averaged mean temperature for 2013 was +1.20°C above the 1961–1990 average. Maximum temperatures were +1.45°C above average, and minimum temperatures +0.94°C above average. Temperatures were above average across nearly all of Australia for maximum, mean and minimum temperatures, with large areas of inland and southern Australia experiencing the highest on record for each (Figure 1).

Australia has experienced just one cooler-than-average year (2011) in the last decade (Figure 2). The 10-year mean temperature for 2004–2013 was 0.50°C above average, the equal-highest on record. Averages for each of the ten-year periods from 1995–2004 to 2004–2013 have been amongst the top ten records.

The Australian mean rainfall total for 2013 was 430 mm (35 mm below the long-term average of 465 mm). In comparison with rainfall in all years since 1900, 2013 sits close to the median or mid-point of historical observations.

Annual rainfall was below average across a large region of the inland east centred on western Queensland and extending into northern South Australia and the Northern Territory. Rainfall was above average over parts of the Pilbara and the south coast of Western Australia, as well as along the east coast and northern Tasmania (Figure 3).

The state of major climate influences during 2013 2013 was a neutral year for the El Niño–Southern Oscillation (ENSO), with neither El Niño or La Niña

Figure 1: 2013 annual mean temperatures compared to historical temperature records.

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Figure 2: Annual mean temperature anomalies for Australia (compared with 1961–1990 average). The black line shows the 10-year moving average. influencing Australian rainfall. Temperatures were generally slightly below normal in the eastern equatorial Pacific, but remained within neutral thresholds for the entire 12 months. In the central equatorial Pacific temperatures were very close to average. The Southern Oscillation Index (SOI) also stayed within the neutral range for most of the year with only occasional, shortlived periods above +10 (a level which would, if sustained, be indicative of La Niña).

A negative phase of the Indian Ocean Dipole (IOD) developed rapidly during late autumn, and remained in place through to the end of July before breaking down in early August. Another feature of the large-scale circulation was a strongly negative phase of the Southern Annular Mode (SAM) in late winter and spring, with the August–October value of the SAM index being the lowest since 1988. The negative IOD phase contributed to above-average rainfall over large parts of Australia in the May–July period, while the negative SAM phase from August–October contributed to above-average rainfall on the southern coastal fringe of Australia (particularly

Tasmania) from August to October and dry and hot conditions in most other parts of the country, especially Queensland and New South Wales.

Frequent stretches of warm days lead to Australia’s warmest year The past year was characterised by persistent and widespread warmth (Figure 4). The annual mean temperature was +1.20°C above the long-term (1961– 1990) average, some +0.17°C above the previous record set in 2005 (+1.03°C). It was also the warmest year on record for South Australia, Western Australia and the Northern Territory. In South Australia, mean temperatures were 0.41°C above the previous record set in 2009. All other States ranked in the top four years: Queensland and New South Wales second, Victoria third and Tasmania fourth.

Both maximum and minimum temperatures were well above average; maximum temperatures were 1.45°C above average, exceeding the previous record set in 2005 by 0.24°C, while minimum temperatures were 0.94°C

Figure 3: 2013 annual rainfall compared to historical rainfall records.

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Figure 4: Australian-averaged daily mean temperature anomalies, compared to the historical average. above average, the second-highest on record. Mean and maximum temperatures were above average over nearly all of Australia and the highest on record over large areas of inland and southern Australia. Minimum temperatures were also the highest on record for parts of the southern mainland, with only small areas near the eastern and northern coastline recording near-average minima.

Numerous heat records were set during the year including: t

Australia’s warmest summer (+1.11°C, for 2012–13) and spring (+1.57°C) on record

t

Australia’s warmest January (+1.76°C) and September (+2.75°C) on record; September’s temperature anomaly was also the largest for any month since at least 1910

t

Australia’s hottest summer day on record (7 January)

t

Australia’s warmest winter day on record (31 August)

Sea surface temperatures in the Australian region Sea surface temperatures (SSTs) around Australia were unusually warm throughout the year (Figure 5), with the monthly anomalies for January and February the highest

on record and that for November the second-highest on record. This extends a period of sustained record-high SSTs in the Australian region since 2010 (Figure 6).

SSTs for 2013 were the third-highest since 1910, 0.51°C above the long-term average. Below-average annual SSTs have not been recorded for the Australian region since 1994 (Figure 6); the region has seen a total rise in SSTs of approximately 1°C since 1910, a similar value to that recorded for atmospheric warming over land.

SSTs were consistently very much above average off the western and southern coast of Australia from summer 2012–13 until May. Strong warm anomalies continued in waters to the south of the mainland throughout 2013. SSTs in the southern region were some 0.59°C above average, surpassing the annual record (+0.56°C in 1999) by 0.03°C.

Recent warming trends continue Australian land and sea surface temperatures have now warmed about 1°C, with the majority of the warming occurring since 1950. For temperatures over land, the past ten years have been the equal-warmest on record while for

Figure 5: 2013 (January–November data) sea surface temperatures compared to historical records. The map will be updated when December data are available Bulletin of the Australian Meteorological and Oceanographic Society Vol. 27 page 9

Figure 6: Annual mean sea surface temperature anomalies in the Australian region (compared with 1961–1990 average). The black line shows the 10-year moving average. sea surface temperatures the past ten years have been the warmest on record.

The Australian region warming is very similar to that seen at the global scale, and the past year emphasises that the warming trend continues. As summarised in the recent Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, recent warming trends have been dominated by the influence of increasing greenhouse gases and the enhanced greenhouse effect.

Near-average annual rainfall, although dry in the inland east National rainfall for 2013 was 35 mm below the longterm average, placing the annual total of 430 mm near the middle of historical observations as the 52nd-driest year on record. Tasmania and Western Australia were the only States to record above-average annual totals, with all other States and the Northern Territory recording between 79 and 92 per cent of their long-term average rainfall.

Drought conditions have affected large parts of Queensland away from the eastern coast, where rainfall has been below average since late 2012. This period included a poor wet season (December–April), leading to the emergence of significant rainfall deficiencies in the region by autumn

2013. Yearly totals were in the lowest 10 per cent of records for much of the west and inland south. Areas of below-average annual rainfall extended into northern inland New South Wales, the eastern Northern Territory and northeastern South Australia. Annual rainfall was also below average over much of the inland southeast with rainfall in the Murray–Darling Basin 24 per cent below average. Victoria saw another below-average rainfall year, meaning that rainfall in 14 of the past 17 years has been below average.

A strip on the central coast of Western Australia, between Learmonth and Morawa, also recorded below-average annual rainfall.

Annual rainfall was substantially higher than average over much of the Pilbara and northern Interior districts of Western Australia, along the east coast between central Queensland and Sydney, in an area around Esperance on the central southern coast of Western Australia. Rainfall was also higher, albeit less significantly so, in northern Tasmania, coastal Victoria and small areas of the tropical north and coastal South Australia.

National annual rainfall has been near-average during the past two years (Figure 7), following very high rainfall

Figure 7: Annual mean rainfall (mm) for Australia since 1900. The black line shows the 10-year moving average.

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during 2010 and 2011, which was associated with La Niña conditions in the tropical Pacific Ocean.

Significant events Heatwaves and persistent warmth The most significant heat event of the year occurred in January1. An extended national heatwave began over the southwest of the continent late in December 2012 before moving into southern and eastern Australia. The heat was notable for its extent and duration, and was easily the longest continent-wide heatwave on record. Temperatures more than 10°C above average were recorded across extensive areas of Australia until 18 January. A national daily average maximum temperature record was set on the 7th (40.30°C) while the highest temperatures were observed on 12–13 January, exceeding 48°C at numerous locations in inland eastern Australia. Moomba reached 49.6°C on the 12th; this was the highest temperature recorded during 2013, the highest in South Australia since 1960 and sixth highest ever officially recorded in Australia.

Hobart and Sydney also experienced their hottest days on record during the event (41.8°C, 4 January and 45.8°C, 18 January respectively).

A near-stationary high pressure system over the Tasman Sea brought persistent heat to south-east Australia over 2–13 March2. South-east South Australia, southern Victoria and Tasmania were most affected. Melbourne experienced nine consecutive days of 30°C or above and seven consecutive nights of 20°C or above, both records for any time of year, while Launceston also set a record with eight consecutive days of 30°C or above.

Unusual warmth was recorded across much of Australia from the last week of August through September3. The national daily average maximum temperature on 31 August (29.92°C) was a record for winter. Warm temperatures were widespread and prolonged, especially away from the coast; a number of national, state and territory records were set for the highest temperature recorded so early in the season. The warmest day in that period was 26 September, when 29% of Queensland (principally the central and southern inland) had its hottest September day on record.

Extreme heat developed over parts of Australia, particularly the eastern interior, during the last week of December. A number of locations in Queensland—including Roma, Injune, Blackall and Urandangi—had their hottest day on record on 29 or 30 December, with December monthly records at several other sites. Further records were set as the event continued into the first days of 20144.

Bushfires Destructive fires occurred in southeast Australia during early 2013. The most destructive was in southeastern Tasmania when a fire started on 4 January rapidly expanded 1

www.bom.gov.au/climate/current/statements/scs43.pdf

2

www.bom.gov.au/climate/current/statements/scs45.pdf

3

www.bom.gov.au/climate/current/statements/scs46.pdf

4

www.bom.gov.au/climate/current/statements/scs47.pdf

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between Forcett and Dunalley (eventually exceeding 25500 ha); 193 dwellings, significant infrastructure and 186 other buildings were destroyed or seriously damaged.

Other destructive fires burnt during January in the Warrumbungles in north-west New South Wales (exceeding 54000 ha, 51 homes destroyed), in Victoria in the Seaton–Glenmaggie area of Gippsland (burnt 75000 ha by month’s end, caused one direct death, destroyed 22 homes) and around Snake Valley and Carngham, west of Ballarat (destroyed nine homes). Grass fires in southern New South Wales caused heavy stock losses. Two longlived fires each burnt more than 30 000 ha in Victoria but caused limited property damage; around Mount Hotham (January–February) and around Victoria Valley in the Grampians National Park (February–March).

A record warm and dry winter and an early spring saw early fire activity on the east coast, culminating in the most destructive fires in the Sydney region since at least 1968.

Fires burnt in the Blue Mountains in early September, followed by significant fires in mid-October; the State Mine–Mount Victoria fire burnt more than 50000 ha to the east and south of Lithgow by month’s end while the Springwood fire, north-west of Penrith, destroyed 193 homes and damaged another 122. Fifteen houses were also lost at Victoria, Lithgow, Wyong, and Balmoral. Other significant fires burnt between late September and midOctober on the Mid North Coast, between Port Stephens and Taree, destroying four homes and 17 other structures; at the Olympic Park Aquatic Centre, in Homebush; and in the north of Wollemi National Park.

Cyclones There were a total of 10 tropical cyclones in the Australian region during the 2012–13 season, slightly below the longterm average of 11; four made landfall as cyclones, two as remnant tropical lows. The most intense at landfall was Rusty, crossing the coast near Pardoo, east of Port Hedland, as a category 4 storm on 27 February. Rusty was large and slow-moving, bringing heavy rain and strong winds to coastal regions, resulting in major flooding in Pilbara catchments and the far western Kimberley with significant rainfall extending as far south as Esperance as the decaying storm travelled south.

The remaining two landfalling cyclones crossed the coast as category 1 storms. Oswald, on the west coast of Cape York Peninsula near Kowanyama on 21 January, causing only minor wind-related impacts at landfall, but extensive flooding where the remnant low caused heavy rainfall.

Peta made landfall near Karratha in Western Australia on 23 January, causing some local flooding in the Pilbara and closing Port Hedland to shipping.

Three cyclones reached the severe classification (category 3 or higher) without making landfall; Narelle (January, category 4) and Victoria (April, category 3) off Western Australia, and Sandra (March, category 3) off Queensland.

None had any significant direct impact on mainland Australia, although storms associated with Narelle caused damage at Karlgarin in southwest Western Australia.

Three storms occurred late in 2013 and will form part of the count for the 2013–14 season; Alessia which made landfall south of Darwin on 24 November as a category 1 storm and again in the southern Gulf of Carpentaria on 28 November, Bruce which travelled southwest away from the coast of Java and eventually reached category 5 strength on 22 December after passing into the South West Indian Ocean basin, and category 3 Christine which crossed the coast of Western Australia near Roebourne overnight on 30–31 December. Alessia caused some localised flooding in the Top End and south of the Gulf of Carpentaria while Christine caused local flooding in the coastal north-west, generally minor wind damage, and power outages.

Flooding The remnants of tropical cyclone Oswald brought heavy rain to much of the east coast from 21 to 29 January. Significant flooding occurred over most coastal catchments from Rockhampton to northern New South Wales, especially severe in the Burnett River catchment and around Bundaberg5 (Special Climate Statement 44).

Damage was also caused by a number of tornadoes in the Bundaberg area, and high winds and storm surges in coastal areas.

A number of other flood events occurred during the remainder of the year, causing localised damage and interrupting transport links, but resulting in limited property inundation. Areas affected included southeast Queensland and coastal New South Wales (late February– early March), south-east Tasmania (8–9 April), the Melbourne area (1–2 June), west and central Gippsland in Victoria (12–14 June), south-east New South Wales and East Gippsland (24–26 June), and north-west Western Australia (early and late June). Frequent heavy rain and generally above-average rainfall during the second half of 2013 led to further flooding in the northern half of Tasmania on multiple occasions during winter and spring.

Severe storms and high winds East Coast Lows caused storm damage and coastal erosion between the central New South Wales coast and south-east Queensland on 23–26 February, with heavy rain continuing into early March causing some localised flooding, again on 24–26 May, and finally in southern coastal New South Wales and East Gippsland on 23–26 June, causing localised flooding.

A cold front passed through northern Victoria and adjacent southern New South Wales on 21 March.

Associated super-cell thunderstorms caused extensive damage and injuries, with at least 20 people requiring hospital attention. Some five tornadoes were confirmed along and south of the border, with those at Violet Town 5

www.bom.gov.au/climate/current/statements/scs44.pdf

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and Cobram/Yarrawonga estimated to have reached at least EF36 intensity (220–266 km/h winds).

There were numerous episodes of damaging winds in southern Australia in winter and spring, most associated with the passage of strong frontal systems. Significant events involving extensive storm and wind damage, power outages and occasional tornado reports occurred on 4–6 July (south-east South Australia, Tasmania and Victoria), 15–22 July (Perth and south-west Western Australia, south-east South Australia, Tasmania), 12 August (Sydney and Melbourne), 16–18 August (southeast South Australia, southern Victoria, Tasmania), 21–22 September (south-west Western Australia from Geraldton to Busselton, including Perth), 25–26 September (southern South Australia, southern New South Wales, Victoria), 30 September–2 October (South Australia, Victoria, Tasmania, southern New South Wales) and 22 October (south-east South Australia and Victoria). The 21–22 September event also brought significant storm surges in the Perth area with coastal and estuarine flooding, while a gust of 143 km/h at Fawkner Beacon in the early hours of 1 October was the third-strongest gust ever recorded in the Melbourne region.

Supercell thunderstorms south-west of Brisbane on the night of 12 June caused property damage in Pratten and Bony Mountain, north-west of Warwick. Heavy rain and flash flooding associated with severe thunderstorms were recorded in Sydney on 28 October, and more broadly from Sydney to south-east Queensland on the 29th. Severe thunderstorms and very large hail were also reported across south-east Queensland and Capricornia during the first half of November, with significant events on the 14th, 16th and 18th when storms also affected coastal New South Wales. There were also storms and hail north of Perth on 16 November, causing significant agricultural losses.

Globally, 2013 the sixth warmest year on record The World Meteorological Organization (WMO) produces an estimated global mean temperature by drawing on data from three global climate datasets maintained by the UK Met Office Hadley Centre (HadCRU4), the US National Climatic Data Centre (blended GHCNv3 and ERSST3b) and the US Goddard Institute of Space Studies (GISTEMP). The estimated global mean temperature for 2013 is 0.50 °C above the long-term (1961–1990) average of 14.0 °C. Using this method, 2013 ranks as the sixthwarmest year since global records commenced in 1880.

No year since 1985 has recorded a below-average global mean temperature and nine of the ten warmest years have occurred in the past 12 years (2002–2013).

6

The Enhanced Fujita Scale of tornadic damage see: http://en.wikipedia.org/wiki/Enhanced_Fujita_scale

Meet a Member

Laura O’Brien Where does this find you?

At my desk on a Monday morning with a large coffee.

What do you do?

I am a Postdoc at Monash University within the Centre of Excellence for Climate System Science. I work on the low frequency variability of the Southern Hemisphere jet stream. My main interest is the dynamics of Rossby waves.

Why did you get into it?

I loved Maths at school so did a degree in Mathematical Sciences. During it I realised that I loved applied maths, particularly maths describing environmental processes.

Since then I have wanted to work on fluid flows in the natural world. I went on to do a Masters in Mathematical Modelling and then a Ph.D. in tsunamis. Afterwards, I wanted to come to Melbourne so I started looking for jobs at the tsunami warning centre in the Bureau of Meteorology but wasn’t having much luck. Then I found this job and thought, ”atmospheric waves… those could be interesting!”

What is the best thing about what you do?

The freedom to explore my own ideas and the opportunities to teach.

What did you want to be when you were 10?

A waitress.... but then I worked as one for long enough to make me change my mind.

How do you relax?

A walk, run, swim or cycle followed by some good food and maybe a cold beer.

What is your favourite holiday destination?

Anywhere that has good scuba diving or skiing.

Bulletin of the Australian Meteorological and Oceanographic Society Vol. 27 page 13

AMOS member Laura O’Brien. Image: Tadhg O’Brien

Snapshot

Cumulus congestus 16 November 2013 William Thurston

This snapshot was taken on a flight between Melbourne and Sydney, looking north-west over New South Wales (Lake Burrinjuck is in the bottom-right of the image) at appoximately 8:00 a.m. and shows two developing cumulus congestus clouds. The cloud in the foreground appears to be fairly shallow and may be breaking through a pileus cloud, where condensation has occurred in a moist layer above the updraft. Nonetheless, the cloud may have reached the tropopause and begun to spread laterally,

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although the same has not happened to the cloud in the background which appears to be of a similar depth. Also notice the curvature of the Earth in the background of the image.

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

Charts from the Past with Blair Trewin

6 January 1994 Strong westerly winds over south-east Australia (extending on occasions into the subtropics) are a regular feature of winter and early spring. These normally bring dry weather to the east coast, and in spring can be associated with extreme fire weather. In mid-summer the subtropical ridge is normally too far south to allow such patterns, but there are occasional exceptions, and a notable one occurred in early January 1994.

Westerly flow dominated the south-east during the end of December and early January, following the development of a deep low in the eastern Bass Strait on 26–27 December which, (similarly to its counterpart five years later) caused havoc in the Sydney-Hobart yacht race (luckily without any loss of life) and washed out large parts of the Boxing Day Test. The westerlies were at their most intense from 6–8 January, with two fronts passing, one on the 6th and a second on the 8th.

The first front was associated with an elongated trough to the north which allowed west to north-west winds to cover most of southern and central Queensland. It is very unusual for such winds to extend so far north in January, and as a result hot inland air was drawn out to the coast with many high temperature records set in eastern parts of Queensland and northern New South Wales. The 6th was an especially hot day, on which all-time records were set at places including Charters Towers (44.9°C), Clermont (45.0°C), Amberley (44.3°C), Warwick (41.7°C), Gatton (44.5°C), all in Queensland, and Casino (44.0°C) in NSW, while further records were set on the 8th at Grafton (43.8°C), Kempsey (43.0°C) and Tenterfield (38.3°C). The pattern’s persistence also meant many records were set for persistent heat, including five successive days above 40°C at Rockhampton and Gayndah, and seven at Charters Towers.

It was not quite as hot in the Sydney region with temperatures generally in the low to mid-30s, but strong westerly winds and dry lead-up conditions (there had been little rain in coastal New South Wales since 10 December) made fire weather conditions particularly dangerous, setting the scene for the most destructive fires ever experienced within metropolitan Sydney. The first significant fires in the area broke out on the 6th but the worst damage was on the 8th as the second front passed.

Four lives were lost (two in Sydney, two elsewhere in the state) and over 200 properties were destroyed, about half of them in the southern suburbs of Jannali and West Como, the remainder in various outbreaks around Lane Cove, on the edges of the Royal and Ku-ring-gai Chase National Parks and in the Northern Beaches area. There were also major fires in the Blue Mountains, the Hunter and around Grafton, and for several days all land routes out of Sydney were closed except for the Hume Highway.

In marked contrast, it was very cool further south.

Even in central and southern inland New South Wales, temperatures were below normal. The 8th, in the wake of the second front, was particularly cool. Snow fell to below 1000 metres in Tasmania, and Mount Hotham had a maximum of only 1.9°C, an Australian record for coolest January day at the time (later broken in 2012), while the next morning a Victorian record night-time low for January, −3.9°C, was set at Falls Creek. Most of southern Victoria failed to reach 18°C on the 8th, and Adelaide had four successive days below 21°C, something which has only occurred twice in January or February in the last 40 years. The persistent westerly flow also brought heavy rain to western Tasmania; Lake Margaret received 168 millimetres in six days from the 4th to the 9th, with at least 15 mm recorded on each day.

Synoptic chart for 0000 UTC (1100 AEDT), 6 January 1994

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The Research Corner with Damien Irving

Testing your code The Climate Institute recently published a series of short interviews online, where they asked a bunch of climate scientists about what keeps them up at night. As you would expect, most of the answers were about sea level rise, heat waves and other projected changes to the climate system. One respondent, however, jokingly remarked that the possibility of bugs in her code was also a major source of stress. While this comment was made in jest, there is no doubt that one of the biggest fears for any scientist is to have someone find an error in your published computational results.

The highest profile case of buggy scientific code occurred back in 2007, involving a biologist at the University of California (Miller, 2006). The bug in question did nothing more than inadvertently flip a single column of data, however its identification resulted in the retraction of five published papers, three of which appeared in Science. These things happen in the weather/climate sciences as well, with a recent Nature article (Ince et al., 2012) highlighting a case back in 2009 where a bug was found to be responsible for substantial errors in the widely used HadCRUT surface temperature dataset. In fact, while the climate science community was exonerated of any wrongdoing in the wake of the IPCC email hacking scandal, a Nature commentary on scientific programming standards pointed out that the email affair was a warning to all scientists to get their houses in order (Merali, 2010): “To all scientists out there, ask yourselves what you would do if, tomorrow, some Republican senator trains the spotlight on you and decides to turn you into a political football. Could your code stand up to attack?”

Given the ramifications of publishing erroneous computational results, you’d think scientists would be the most conscientious code testers going around.

Unfortunately, this could not be farther from the truth.

The development process followed by many scientists (myself included until very recently) goes something like this: write a chunk of code, check (in a rather ad hoc fashion) whether the output “looks” as you might expect, then move on to the next chunk. The lack of any real system to this approach is problematic for a number of reasons: 1.

In six months time you won’t be able to remember if (or how thoroughly) you tested the code

2.

Upon altering a particular section of the code, you have no way of quickly checking if all the other dependent sections still work properly

3.

There’s a good chance you haven’t even come close to testing the full range of possible modes of failure

Bulletin of the Australian Meteorological and Oceanographic Society Vol. 27 page 16

Since most scientists spend their days meticulously testing and re-testing research hypotheses, it seems a little odd that their code testing would be so lax. Perhaps time pressures have something to do with it, but in the long run code testing actually saves time, so that’s probably not it.

Instead, I think the problem arises because most scientists are self-taught programmers. They spend little (if any) time interacting with professional programmers, which means they are simply unaware of the standard testing practices used in the software development industry. This article is an attempt to summarise those practices, as they relate to scientific computing.

To test or not to test?1 It goes without saying that a complex program requires a much higher investment in testing than a simple one. A short script that is only going to be used once to produce a single figure probably doesn’t need separate testing: its output is either correct or not. On the other hand, consider a hypothetical script you’re writing to perform spatial interpolation. None of your favourite off-the-shelf packages (e.g. CDO) provide a function for this particular type of interpolation—which is a bummer because you don’t need to test those—so you’re writing it from scratch.

You’re also going to be executing this code thousands of times to process the output from a global climate model that you’re running. It’s pretty obvious that this code will require thorough testing.

Once the decision to test has been made, it’s important to understand that testing can only do so much. Suppose you are testing a function that compares two 7-digit phone numbers. There are 107 such numbers, which means there are 1014 possible test cases. At a million tests per second, it would take 155 days to run them all. And that’s only one simple function: exhaustively testing a real program with hundreds or thousands of functions, each taking half a dozen arguments, would take many times longer than the expected lifetime of the universe. And how would you actually write 1014 tests? More importantly, how would you check that the tests themselves were all correct?

In reality, all that testing can do is show that there might be a problem in a piece of code. If testing doesn’t find a failure, there could still be bugs lurking that just weren’t picked up. And if testing says there is a problem, it could well be a problem with the test rather than the program.

So why test? Because it’s one of those things that shouldn’t work in theory, but is surprisingly effective in practice. It’s just like mathematics: any theorem proof might contain a flaw that just hasn’t been noticed yet, but somehow we manage to make progress.

1 This section has been adapted with permission from the ‘Software Quality’ chapter of the Software Carpentry Instructors Guide (https://github.com/swcarpentry/guide/blob/master/quality.html)

Introducing the unit test…

The core of code testing is the unit test, which checks the correctness of a single unit of software (typically a single function or method). There are excellent off-the-shelf unit testing libraries available for pretty much all programming languages, with some languages like Python offering multiple different options. Making sense of these options can be a little confusing, however the basic premise for most of them goes something like this: 1.

Write a bunch of tests (i.e. small functions) that each culminate in an assertion (true/false statement)

2.

Store these test functions in a file that is completely separate from the code you are testing (e.g. if you’re testing interpolation.py, store the tests in unittest_ interpolation.py)

3.

Instruct the unit testing library to execute all the tests in the file. It will then report their success/failure to the screen.

You can see that unittest_interpolation.py now contains a complete history of the testing you’ve done. If you make a change to interpolation.py or come back 6-months later and can’t remember if you’ve tested it, you can simply rerun the unit testing library over unittest_interpolation. py to check that the code isn’t broken. In the software industry this is known as regression testing—the practice of re-running pre-existing tests after changes have been made to the code, in order to make sure it hasn’t regressed.

To see the unit testing process in action, check out the Software Carpentry lesson on unit testing2.

What should we be testing?

Now that we know how to unit test, we need to consider what to test. In other words, how do we validate and verify a program? Verification basically asks whether our program is free of bugs, while validation considers if we are implementing the right model or building the right thing. The latter obviously depends on the specific science you’re doing, and typically isn’t something a formal unit test would be written for. For verification testing on the other hand, there are a few generic types of unit test: 1.

Tests for success: Does the code give the correct answer?

2.

Tests for failure: Not only should a function succeed when given good input, it should also fail (in the way you would expect it to fail) when given bad input.

3.

Tests for sanity: Often a unit of code will contain a set of reciprocal functions (e.g. where one converts A to B and the other converts B to A). In these cases, it is useful to create a sanity check to make sure that you can convert A to B and back to A without losing precision, incurring rounding errors, or triggering any other sort of bug.

As well as writing tests for all the individual units (or functions) that are the building blocks of your code, it’s 2

http://software-carpentry.org/v4/test/unit.html

Bulletin of the Australian Meteorological and Oceanographic Society Vol. 27 page 17

also important to write tests for those functions further up the food chain (i.e. the functions that join together all the smaller functions in order to achieve the task at hand).

This process of checking if all the units work properly together is called integration testing.

From personal experience, I’ve found that integration tests don’t always naturally culminate in a simple assertion.

Instead, they sometimes culminate in a plot that requires visual inspection. This kind of makes sense when you think about it, since a plot is often the end product of an analysis. However, since the checking of a plot can’t be automated like assertion testing, you don’t want to find yourself writing too many tests like this.

So now we know that we should be writing tests for success, failure, sanity, and integration. The next question is: how many tests should we be writing? As previously discussed, for our 7-digit phone number function there was a staggering 1014 possible tests for success, which is obviously a little impractical. Fortunately, the answer is common sense: of all the possible tests out there, we only want those that are most likely to give us useful information that we don’t already have. We should therefore try to choose tests that are as different from each other as possible, so that we force the code we’re testing to execute in all the different ways it can. Another way of thinking about this is that we should try to find boundary cases. If a function works for zero, one, and a million values, it will probably work for all values in between.

Code coverage Besides “unit test”, the next most common phrase you’ll hear programmers throwing around in relation to testing is “code coverage”. Rather confusingly, this can refer to the coverage of the unit tests they’ve written, or the coverage of the application code itself. With respect to the former, the code coverage of a set of tests refers to the percentage of the application code those tests exercise. It is often used as a rough indication of how well tested a piece of software is—if the coverage of a set of tests is less than 100%, then some lines of code aren’t being tested at all.

However, even 100% coverage doesn’t guarantee that the code has been completely tested. You can have situations where even though every line is exercised at least once, there are paths through the code that aren’t ever taken (i.e. there’s a difference between line coverage and path coverage). While code coverage isn’t sufficient to show that everything has been tested, it’s still useful. Most languages have tools to test the coverage of your tests—the simplest tool in Python, for instance, is called coverage.py.

The coverage of the actual code itself (as opposed to the coverage of the tests), considers whether all the functions and variables have been used. In other words, coverage of less than 100% suggests that you’ve created an unused function or imported an unused module. As you might have guessed, there are tools to check for this type of code coverage as well (e.g. for Python programming I use Pylint).

Test driven development (TDD) TDD refers to the concept of writing your tests before writing the actual application code. This may seem backward, but the process of writing the tests helps to clarify the purpose of the code in your own mind (i.e. it serves as a design aid), and also helps ensure that tests actually get written. Some programmers swear by TDD and follow it very closely, while others are not so enthusiastic.

Unfortunately the literature on the topic doesn’t provide much clarity either: a recent meta-study (Rafique and Mišić, 2013) didn’t find TDD to have a significant impact on programmer productivity, however that might just be because we don’t really know how to measure programmer productivity. Whether you’re convinced by the TDD advocates or not, it has enough support to suggest that (a) it’s probably something you should try at least once, and (b) testing, whether it be before, during, or after the fact, should be a fundamental cornerstone of what you’re doing.

Conclusion3 The sad fact is that bugs are part and parcel of programming, much like road accidents are part and parcel of driving a 3 When I posted this conclusion on my blog I got the following comment, which I think is important to note: “I wouldn’t compare bugs with auto accidents. Most drivers go a long time before having their first accident (if they ever have one). But every programmer starts off by writing many bugs. And continues to do so frequently throughout his/ her career.”

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car. Even if you always stick to the speed limit and drive ultra-conservatively, there’s no guarantee that you won’t one day have an accident. Similarly, even if you follow the advice of this post to a tee, there’s no guarantee that you won’t one day publish a computation-related retraction (although hopefully not for an article in Science!). You will, however, greatly reduce the risks. You’ll also find collaboration much easier because let’s face it, nobody likes getting into a car with an erratic, lead-footed driver.

References Ince, D.C., Hatton, L., and Graham-Cumming, J., 2012.

The case for open computer programs, Nature, 482, 485– 488.

Merali, Z., 2010. Computational science: …Error. Nature, 467, 775–777.

Miller, G., 2006. A scientist’s nightmare: software problem leads to five retractions. Science, 314, 1856–1857.

Rafique, Y., and Mišić, V.B., 2013. The effects of Test-Driven Development on external quality and productivity: a meta-analysis. IEEE Transactions on Software Engineering, 39, 835–856.

Calendar

2014

17–20 42nd Conference on Broadcast Meteorology, Olympic Valley, CA, USA.

March

July

31–4 April 31 AMS Conference on Hurricanes and Tropical Meteorology, San Diego, California, USA.

7–11 14th Conference on Cloud Physics, Westin Copley Place, Boston, MA, USA.

April

7–11 14th Conference on Atmospheric Radiation, Westin Copley Place, Boston, MA, USA.

st

7–9 9th Weather Radar and Hydrology (WRaH) International Symposium, Washington, DC, USA. 27–2 May European Geosciences Union, General Assembly, Vienna, Austria.

May 12–15 2nd Conference on Atmospheric Biogeosciences, Portland, OR, USA.

28–1 August 11th Annual Asia Oceania Geosciences Meeting, Sapporo, Japan.

August 16–21 1st World Weather Open Science Conference, Montreal, Canada.

September

12–15 31st Conference on Agricultural and Forest Meteorology, Portland, OR, USA.

22–26 13th Quadrennial ICACGP Symposium, Natal, Brazil.

25–30 1st International Summit on Tornadoes and Climate Change, Chania, Crete, Greece.

2015

June

January

9–13 21 Symposium on Boundary Layers and Turbulence, Leeds, UK. st

14–19 15th International Conference on Atmospheric Electricity (ICAE 2014), Norman, OK, USA. 16–20 21st Conference on Applied Climatology, Boulder, CO, USA. 16–20 17th Symposium on Meteorological Observation and Instrumentation, Boulder, CO, USA.

4–8 95th AMS Annual Meeting, Phoenix, USA.

June 22–2 July 26th General Assembly of the International Union of Geodesy and Geophysics, Prague, Czech Republic

July 15–17 AMOS National Conference, Brisbane.

Australian Meteorological and Oceanographic Journal

Articles — Vol. 63 No. 3, September 2013 Dowdy et al. Understanding rainfall projections in relation to extratropical cyclones in eastern Australia.

Gabric et al. Global simulations of the impact on contemporary climate of a perturbation to the sea-to-air flux of dimethylsulphide.

Parker and Lane Trapped mountain waves during a light aircraft accident.

Zhu et al. Spatiotemporal analysis of MODIS and AMSR-E derived SST in joining area of Asia and IndianPacific Ocean.

Grainger et al. The estimated potential predictability of seasonal mean Australian surface temperature Physick et al. Boundary-layer observations in the Pilbara coastal region.

Bulletin of the Australian Meteorological and Oceanographic Society Vol. 27 page 19

Fleming and Awange Comparing the version 7 TRMM 3B43 monthly precipitation product with the TRMM 3B43 version 6/6A and BoM datasets for Australia Regular features: Reid et al. Seasonal climate summary Southern Hemisphere (spring 2012): warmer and drier across much of Australia, along with a new Southern Hemisphere sea ice extent record.

White and Fox-Hughes. Seasonal climate summary Southern Hemisphere (summer 2012–13): Australia’s hottest summer on record and extreme east coast rainfall.

Wu. Quarterly numerical weather prediction model performance summary—July to September 2013.

BAMOS Author Guidelines

For all submissions: The Bulletin of the Australian Meteorological and Oceanographic Society (BAMOS) accepts short (<2500 words) contributions of original research work for peerreview and consideration in the “Science Articles” section.

Longer articles will be considered at the discretion of the Editor and Editor-in-Chief. Articles submitted to BAMOS should also be appropriate for the whole AMOS community (from weather enthusiasts to professional members) and should aim to be concise without using excessive scientific jargon.

For the peer-reviewed “Science Articles” section, authors should follow these guidelines: 1.

Articles should be submitted as a PDF or Word document (or similar) for peer-review and include all figures and tables either within the main text or consecutively at the end of the article.

2.

Articles should have a line spacing of 1.5 or more using a font size of 12. Articles should preferably be written using Times New Roman or Arial.

3.

Articles should be split into sections, with the heading for each section numbered consecutively and using a font size of 14. For example (these are title examples, headings are made at the authors’ discretion):

t

Raymond, D.J., 1993. Chapter 2: Observational constraints on cumulus parameterizations. In: The representation of cumulus convection in numerical models, Meteorological Monographs, 24 (46), 17–28, American Meteorological Society, Boston, USA. t

t

4.

An abstract is not required; however, should the author(s) wish to produce one it should not be more than 150 words in length.

5.

Acknowledgements to be included after the final work section and before the references.

6.

References should follow these example formats:

t

Journal Articles:

Jung, T., Ferranti, L. and Tompkins, A.M., 2006, Response to the summer of 2003 Mediterranean SST anomalies over Europe and Africa, Journal of Climate, 19, 5439–5454. t

Books:

Holton, J.R., 2004, An Introduction to Dynamic Meteorology. Academic Press, New York. 535 pp.

Bulletin of the Australian Meteorological and Oceanographic Society Vol. 27 page 20

Web sites:

Department of Sustainability and Environment, 2012, Bushfire history - Major bushfires in Victoria, www.dse. vic.gov.au/fire-and-other-emergencies/major-bushfiresin-victoria/ 7.

We recommend that the author(s) make at least two suggestions for referees to undertake the peer-review.

8.

Once peer-review has been completed, a final version of the document should be sent to the editor either in Word format or as plain text. The document should also include figure and table captions and the references but no figures. Figure files should be sent separately (they may be in any format and the editor will confer with the author(s) on the resolution and formatting).

9.

Galley-proofs will be sent to the author(s) for final checking before publication.

2. Method 4. Conclusions

Theses:

Trewin, B., 2001, Extreme temperature events in Australia.

PhD Thesis, School of Earth Sciences, University of Melbourne, Australia.

1. Introduction 3. Results

Book chapter:

BAMOS also accepts a wide range of non-peer-reviewed work, for example news items, charts from the past, conference reports, book reviews, biographical articles and meet a member. AMOS members are therefore encouraged to submit articles that would be of general interest to the AMOS community without necessarily requiring peer review. File formats should follow those given above; a word or plain text document should be submitted (which includes any figure captions and tables) along with any figure files given separately.

All articles should be either posted or emailed to the editor with any questions on the formatting also directed to the editor (see the inside back cover of this issue for contact details).

2014 AMOS Council Executive

President Vice-President Secretary Treasurer Past President

Todd Lane Mary Voice Damien Irving Angela Maharaj Blair Trewin

Ordinary Members Ailie Gallant Andrew Klekociuk Neville Nicholls Ian Watterson

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

03-8344 6516 03-8344 6911 02-9385 0593 03-9669 4623

Sub-Committee Convenors Public Relations Awards 2015 Conference Education

Centre Chairs NSW Hobart Melbourne ACT Perth Darwin Brisbane Adelaide

Vacant Mark Williams Andrew Weibe Phillip Riley

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Fiona Johnson Kelvin Michael Louise WIlson Bob Cechet Merv Lynch Ian Shepherd Andrew Wiebe Darren Ray

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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..

2014 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) Shannon Mason (Melbourne) Fiona Johnson (NSW) Clem Davis (ACT)

Contributors Blair Trewin Damien Irving

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 28 March 2014. 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