All hail new weather radar technology, which can spot hailstones lurking in thunderstorms

Joshua Soderholm, The University of Queensland; Alain Protat, Australian Bureau of Meteorology; Hamish McGowan, The University of Queensland; Harald Richter, Australian Bureau of Meteorology, and Matthew Mason, The University of Queensland

An Australian spring wouldn’t be complete without thunderstorms and a visit to the Australian Bureau of Meteorology’s weather radar website. But a new type of radar technology is aiming to make weather radar even more useful, by helping to identify those storms that are packing hailstones.

Most storms just bring rain, lightning and thunder. But others can produce hazards including destructive flash flooding, winds, large hail, and even the occasional tornado. For these potentially dangerous storms, the Bureau issues severe thunderstorm warnings.

For metropolitan regions, warnings identify severe storm cells and their likely path and hazards. They provide a predictive “nowcast”, such as forecasts up to three hours before impact for suburbs that are in harm’s way.

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Read more: To understand how storms batter Australia, we need a fresh deluge of data

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When monitoring thunderstorms, weather radar is the primary tool for forecasters. Weather radar scans the atmosphere at multiple levels, building a 3D picture of thunderstorms, with a 2D version shown on the bureau’s website.

This is particularly important for hail, which forms several kilometres above ground in towering storms where temperatures are well below freezing.

Bureau of Meteorology 60-minute nowcast showing location and projected track of severe thunderstorms in 10-minute steps.
Australian Bureau of Meteorology

In terms of insured losses, hailstorms have caused more insured losses than any other type of severe weather events in Australia. Brisbane’s November 2014 hailstorms cost an estimated A$1.41 billion, while Sydney’s April 1999 hailstorm, at A$4.3 billion, remains the nation’s most costly natural disaster.

Breaking the ice

Nonetheless, accurately detecting and estimating hail size from weather radar remains a challenge for scientists. This challenge stems from the diversity of hail. Hailstones can be large or small, densely or sparsely distributed, mixed with rain, or any combination of the above.

Conventional radars measure the scattering of the radar beams as they pass through precipitation. However, a few large hailstones can look the same as lots of small ones, making it hard to determine hailstones’ size.

A new type of radar technology called “dual-polarisation” or “dual-pol” can solve this problem. Rather than using a single radar beam, dual-pol uses two simultaneous beams aligned horizontally and vertically. When these beams scatter off precipitation, they provide relative measures of horizontal and vertical size.

Therefore, an observer can see the difference between flatter shapes of rain droplets and the rounder shapes of hailstones. Dual-pol can also more accurately measure the size and density of rain droplets, and whether it’s a mixture or just rain.

Together, these capabilities mean that dual-pol is a game-changer for hail detection, size estimation and nowcasting.

Into the eye of the storm

Dual-pol information is now streaming from the recently upgraded operational radars in Adelaide, Melbourne, Sydney and Brisbane. It allows forecasters to detect hail earlier and with more confidence.

However, more work is needed to accurately estimate hail size using dual-pol. The ideal place for such research is undoubtedly southeast Queensland, the hail capital of the east coast.

When it comes to thunderstorm hazards, nothing is closer to reality than scientific observations from within the storm. In the past, this approach was considered too costly, risky and demanding. Instead, researchers resorted to models or historical reports.

The Atmospheric Observations Research Group at the University of Queensland (UQ) has developed a unique capacity in Australia to deploy mobile weather instrumentation for severe weather research. In partnership with the UQ Wind Research Laboratory, Guy Carpenter and staff in the Bureau of Meteorology’s Brisbane office, the Storms Hazards Testbed has been established to advance the nowcasting of hail and wind hazards.

Over the next two to three years, the testbed will take a mobile weather radar, meteorological balloons, wind measurement towers and hail size sensors into and around severe thunderstorms. Data from these instruments provide high-resolution case studies and ground-truth verification data for hazards observed by the Bureau’s dual-pol radar.

Since the start of October, we have intercepted and sampled five hailstorms. If you see a convoy of UQ vehicles heading for ominous dark clouds, head in the opposite direction and follow us on Facebook instead.

UQ mobile radar deployed for thunderstorm monitoring.
Kathryn Turner

Unfortunately, the UQ storm-chasing team can’t get to every severe thunderstorm, so we need your help! The project needs citizen scientists in southeast Queensland to report hail through #UQhail. Keep a ruler or object for scale (coins are great) handy and, when a hailstorm has safely passed, measure the largest hailstone.

Submit reports via uqhail.com, email, Facebook or Twitter. We greatly appreciate photos with a ruler or reference object and approximate location of the hail.

How to report for uqhail.

Combining measurements, hail reports and the Bureau of Meteorology’s dual-pol weather radar data, we are working towards developing algorithms that will allow hail to be forecast more accurately. This will provide greater confidence in warnings and those vital extra few minutes when cars can be moved out of harm’s way, reducing the impact of storms.

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Read more: Tropical thunderstorms are set to grow stronger as the world warms

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Advanced techniques developed from storm-chasing and citizen science data will be applied across the Australian dual-pol radar network in Sydney, Melbourne and Adelaide.

Who knows, in the future if the Bureau’s weather radar shows a thunderstorm heading your way, your reports might even have helped to develop that forecast.

Joshua Soderholm, Research scientist, The University of Queensland; Alain Protat, Principal Research Scientist, Australian Bureau of Meteorology; Hamish McGowan, Professor, The University of Queensland; Harald Richter, Senior Research Scientist, Australian Bureau of Meteorology, and Matthew Mason, Lecturer in Civil Engineering, The University of Queensland

This article was originally published on The Conversation. Read the original article.

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World-first continental acoustic observatory will listen to the sounds of Australia

Solar-powered arrays can be left in remote locations, recording high-quality audio for years.
Supplied

David M Watson, Charles Sturt University

To me, the sound of a healthy wetland is like a symphony: crickets, frogs and splashing waterbirds; the dawn chorus with occasional jets flying overhead; even the odd donkey.

But add cane toads to the mix and it becomes a monotone dirge – the trilling, birdlike call of the toads and nothing else.

Healthy wetlands are a symphony of animals and sounds.
Australian Acoustic Observatory/David Watson, Author provided799 KB (download)

Once cane toads colonise an area, their cries drown out everything else.
Acoustic Observatory/David Watson, Author provided2.99 MB (download)

The significance of sound in ecosystems is what prompted my colleagues and me to develop a world-first acoustic observatory, made up of 400 permanent sensors embedded across the entire continent.

Three test sites, in inland woodlands, wetlands in Northern Australia, and subtropical forest remnants, have illustrated how we can use sound to track the movement of invasive species, the impact of climate change, and the health of remote ecosytems.

Now, with the support of five universities and a grant from the Australian Research Council, we are working to install acoustic sensors in ecosystems across Australia. By mid-2018 the full array will be in place. And once we begin recording, every minute will be made available to everybody online.

How it works

While audio has been used around the world in ecological research, Australia is the perfect candidate for a continent-wide recording array. We have many excellent ecologists and computer scientists concentrated in a small number of places, within a vast and sparsely populated country.

The difficulty of regularly visiting many parts of the nation, combined with the growth in digital technology and storage, means it is now feasible to leave recording devices in place for weeks – or in our case, years.

By the middle of 2018, 400 sensors will be installed across Australia.
David Watson, Author provided

Each array is built around a steel pole concreted into the ground. At the top is a solar panel, about the size of an A2 sheet of paper, which is connected to a battery to keep the digital recorder powered through overcast days.

We don’t yet have the ability to upload the data remotely (largely because of Australia’s lack of internet bandwidth), so for now we need to visit each array every six months or so to swap out the SD cards.

Once the data are collected, it will all be uploaded to the internet and made available for free. One of our hopes is that anyone with an interest in nature, from school teachers to artists and more people besides, will engage with this project.

Visualising time

One of the strengths of this project is our ability to use sound to picture time. We can prepare fascinating visualisations that contain months’ worth of data in a single image.

Some of the effects we’re measuring, such as the impact of cane toads and other invasive species, have very obvious acoustic signatures. They are dramatic to hear, but even more striking to see in a sonograph (essentially a graph of sound).

A 24 hour recording rendered as a false-colour spectrogram. Different sound signatures are assigned colours, making patterns over time visible.
Michael Towsey, Anthony Truskinger, and Paul Roe

We’ve pioneered the use of false-colour spectrograms to visualise long duration recordings. These make clear the flattening effect of invasive species, or the long-term subtle shifts caused by climate change.

The other major advantage of our remote arrays is that animals aren’t disturbed by humans frequently coming and going, which allows us to collect interesting and sometimes surprising data.

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Emus, for example, are attracted to shiny things – so a big shiny thing in the desert will catch their attention. And if you’ve heard them, you know they also have a pretty strange call, like a deep rolling boom.

When a big mob of 30 or so birds come across an array you can definitely hear it. From a nice quiet desert dune, with gusts of wind and small birds chirping, you’ll hear a little “oo-oo-oo”. And then there’s another, and another – and then it’s like a football crowd, with all of them investigating the array, pushing it around and mucking about with each other.

These continuous recordings of distinctly Australian soundscapes are surprisingly evocative. Ultimately, this acoustic observatory will not just allow environmental scientists to take the pulse of Australia’s ecosystem – it will also represent the most avant-garde radio imaginable, with 400 stations playing their own unique mix.

David M Watson, Professor in Ecology, Charles Sturt University

This article was originally published on The Conversation. Read the original article.

New Royal Commission into water theft may be just the tip of iceberg for the Murray Darling Basin

Jamie Pittock, Australian National University

Last weekend South Australian Premier Jay Weatherill announced the establishment of a Royal Commission to investigate breaches of the Murray Darling Basin Agreement.

This follows apparently egregious behaviour by some irrigators and state government regulators in New South Wales. Yet the alleged theft of water in the Murray-Darling Basin is only the tip of the iceberg when we consider the institutional problems – namely the capture of state government agencies by powerful irrigation interests.

Take NSW as an example. In 1993 the then state Department of Water Resources’ North west rivers audit found the same theft, meter-tampering and questionable government oversight exposed again by the ABC’s Four Corners investigation in July.

Only half of the targeted volume of salt has been flushed out to sea and the water supply to Broken Hill and other communities has become unreliable. Moreover, floodplain forests and wetlands of international significance continue to decline, and native fish and water bird populations have flatlined.

In fact, many values are at risk in the river system that supplies water to more than 3 million people, and covers a seventh of Australia’s landmass. It is not only a few (alleged) bad apples, it is governance of water that is broken.

Problems with the existing plan

While bad behaviour in NSW is evident, of more concern is the way some state governments are frustrating implementation of the A$13 billion 2012-26 Basin Plan and associated programs to recover water for the river system.

If the Basin Plan is to improve the health of the river and its extensive floodplain forests along the lower River Murray, the water recovered for the environment needs to be released in pulses. That will be the best way to ensure it can rise out of the river channel and inundate wetlands.

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Read more: Is the Murray-Darling Basin Plan broken?

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In this context it is unhelpful for the Victorian Government to propose flows of around half the previously agreed size because of the objections of a small number of landowners along the Goulburn River in its Goulburn key focus area project.

Upstream, state governments have rules that allow water purchased by taxpayers for the river to be extracted by irrigators when it crosses state borders. However, they are failing to remove bottlenecks that prevent managed floods from travelling safely down rivers. They have even proposed to reduce the water available for the environment below minimum requirements.

Astonishingly, 30% of water extraction points in the Basin are still not metered and the information that is collected is not publicly available or audited so that theft can be penalised.

Sustainable management required

Sustainable management of the Murray-Darling Basin requires trust and cooperation among the responsible state, ACT and federal governments.

The alleged water theft in NSW breaks that trust, especially for SA as the downstream state that relies on the River Murray. But so too does the stalling of implementation of the Basin Plan agreement and manipulation of the rules that govern who gets what water and when they get it.

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Read more: ‘Tax returns for water’: satellite-audited statements can save the Murray-Darling

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The foundation of trust is transparency. As a start, there are many opportunities for online recording of water allocations and use to increase trust. It is still possible to fix implementation of the Plan.

In a report released yesterday the Wentworth Group of Concerned Scientists has identified several solutions, including metering all water diversions, completing water recovery, and investing in regional development.

The good news is that there are signs of political leadership. The Council of Australian Governments promised in June to deliver the Basin Plan “in full and on time” for its planned commencement in 2019.

Recently, Prime Minister Malcolm Turnbull recommitted the federal government to Basin Plan implementation. He endorsed the far-reaching recommendations of the Murray-Darling Basin Authority’s Basin-wide Compliance Review to strengthen enforcement of water laws and the Basin Plan, and to recover the remaining environmental water.

The SA Royal Commission

Beginning in 2018, Weatherill’s newly announced Royal Commission will investigate breaches of the Murray Darling Basin Agreement, and the Commissioner “will examine the adequacy of existing legislation and practices and make recommendations for any necessary changes.”

Most significantly, Weatherill has proposed going beyond water theft to “look into whether any legislative or policy changes since the agreement was signed in 2012 have been inconsistent with the purpose of the Basin Agreement and Basin Plan”.

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Read more: We need more than just extra water to save the Murray-Darling Basin

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The Royal Commission’s terms of reference are not yet available and the extent of cooperation of upstream governments is highly uncertain (NSW has already said it will not cooperate). Yet the Royal Commission could help identify ways to better meter and account for water, improve compliance and set rules to protect environmental water.

At the next Basin Ministerial Council meeting later this year the governments need to map out measures to put the Plan back on track. If it can do so, it will be endorsed at the Council of Australian Governments in 2018. This is their opportunity to articulate precisely how they will fulfil their commitment to delivering the basin plan in full and on time.

The Murray-Darling Basin Plan is not perfect. Implementation has problems, but with the remaining $5.1 billion allocated funds and proper leadership it can be well implemented to benefit both people and the environment.

Jamie Pittock, Director, International Programs, UNESCO Chair in Water Economics and Transboundary Water Governance, Australian National University

This article was originally published on The Conversation. Read the original article.