How bushfires and rain turned our waterways into ‘cake mix’, and what we can do about it



The Murray River at Gadds Reserve in north east Victoria after Black Summer bushfires.
Paul McInerney, Author provided

Paul McInerney, CSIRO; Anu Kumar, CSIRO; Gavin Rees, CSIRO; Klaus Joehnk, CSIRO, and Tapas Kumar Biswas, CSIRO

As the world watched the Black Summer bushfires in horror, we warned that when it did finally rain, our aquatic ecosystems would be devastated.

Following bushfires, rainfall can wash huge volumes of ash and debris from burnt vegetation and exposed soil into rivers. Fires can also lead to soil “hydrophobia”, where soil refuses to absorb water, which can generate more runoff at higher intensity. Ash and contaminants from the fire, including toxic metals, carbon and fire retardants, can also threaten biodiversity in streams.




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The sweet relief of rain after bushfires threatens disaster for our rivers


As expected, when heavy rains eventually extinguished many fires, it turned high quality water in our rivers to sludge with the consistency of cake mix.

In the weeks following the first rains, we sampled from these rivers. This is what we saw.

Sampling the upper Murray River

Of particular concern was the upper Murray River on the border between Victoria and NSW, which is critical for water supply. There, the bushfires were particularly intense.

Sludge in Horse Creek near Jingellic following storm activity after the fire.
Paul McInerney/Author Provided

When long-awaited rain eventually came to the upper Murray River catchment, it was in the form of large localised storms. Tonnes of ash, sediment and debris were washed into creeks and the Murray River. Steep terrain within burnt regions of the upper Murray catchment generated a large volume of fast flowing runoff that carried with it sediment and pollutants.

We collected water samples in the upper Murray River in January and February 2020 to assess impacts to riverine plants and animals.

Our water samples were up to 30 times more turbid (cloudy) than normal, with total suspended solids as high as 765 milligrams per litre. Heavy metals such as zinc, arsenic, chromium, nickel, copper and lead were recorded in concentrations well above guideline values for healthy waterways.

Ash and sediment blanketing cobbles in the Murray River.
Paul McInerney/Author Provided

We took the water collected from the Murray River to the laboratory, where we conducted a number of toxicological experiments on duckweed (a floating water plant), water fleas (small aquatic invertebrates) and juvenile freshwater snails.

What we found

During a seven-day exposure to the bushfire affected river water, the growth rate of duckweed was reduced by 30-60%.

The water fleas ingested large amounts of suspended sediments when they were exposed to the affected water for 48 hours. Following the exposure, water flea reproduction was significantly impaired.

And freshwater snail egg sacs were smothered. The ash resulted in complete deaths of snail larvae after 14 days.




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Before and after: see how bushfire and rain turned the Macquarie perch’s home to sludge


These sad impacts to growth, reproduction and death rates were primarily a result of the combined effects of the ash and contaminants, according to our preliminary investigations.

But they can have longer-term knock-on effects to larger animals like birds and fish that rely on biota like snail eggs, water fleas and duckweed for food.

What happened to the fish?

Immediately following the first pulse of sediment, dead fish (mostly introduced European carp and native Murray Cod) were observed on the bank of River Murray at Burrowye Reserve, Victoria. But what, exactly, was their cause of death?

A dead Murray Cod found on the banks of the Murray River following storms after the bushfires.
Paul McInerney/Author Provided

Our first assumption was that they died from a lack of oxygen in the water. This is because ash and nutrients combined with high summer water temperatures can trigger increased activity of microbes, such as bacteria.

This, in turn can deplete the dissolved oxygen concentration in the water (also known as hypoxia) as the microbes consume oxygen. And wide-spread hypoxia can lead to large scale fish kills.




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Click through the tragic stories of 119 species still struggling after Black Summer in this interactive (and how to help)


But to our surprise, although dissolved oxygen in the Murray River was lower than usual, we did not record it at levels low enough for hypoxia. Instead, we saw the dead fish had large quantities of sediment trapped in their gills. The fish deaths were also quite localised.

In this case, we think fish death was simply caused by the extremely high sediment and ash load in the river that physically clogged their gills, not a lack of dissolved oxygen in the water.

These findings are not unusual, and following the 2003 bushfires in Victoria fish kills were attributed to a combination of low dissolved oxygen and high turbidity.

So how can we prepare for future bushfires?

Preventing sediment being washed into rivers following fires is difficult. Installing sediment barriers and other erosion control measures can protect specific areas. However, at the catchment scale, a more holistic approach is required.




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One way is to increase efforts to re-vegetate stream banks (called riparian zones) to help buffer the runoff. A step further is to consider re-vegetating these zones with native plants that don’t burn easily, such as Blackwood (Acacia melanoxylin).

Streams known to host rare or endangered aquatic species should form the focus of any fire preparation activities. Some species exist only in highly localised areas, such as the endangered native barred galaxias (Galaxias fuscus) in central Victoria. This means an extreme fire event there can lead to the extinction of the whole species.

Ash and dead fish on the banks of the Murray River near Jingellic following Black Summer fires.
Paul McInerney/Author Provided

That’s why reintroducing endangered species to their former ranges in multiple catchments to broaden their distribution is important.

Increasing the connectivity within our streams would also allow animals like fish to evade poor water quality — dams and weirs can prevent this. The removal of such barriers, or installing “fish-ways” may be important to protecting fish populations from bushfire impacts.

However, dams can also be used to benefit animal and plant life (biota). When sediment is washed into large rivers, as we saw in the Murray River after the Black Summer fires, the release of good quality water from dams can be used to dilute poor quality water washed in from fire affected tributaries.




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Citizen scientists can help, too. It can be difficult for researchers to monitor aquatic ecosystems during and immediately following bushfires and unmanned monitoring stations are often damaged or destroyed.

CSIRO is working closely with state authorities and the public to improve citizen science apps such as EyeOnWater to collect water quality data. With more eyes in more areas, these data can improve our understanding of aquatic ecosystem responses to fire and to inform strategic planning for future fires.

These are some simple first steps that can be taken now.

Recent investment in bushfire research has largely centred on how the previous fires have influenced species’ distribution and health. But if we want to avoid wildlife catastrophes, we must also look forward to the mitigation of future bushfire impacts.The Conversation

Paul McInerney, Research scientist, CSIRO; Anu Kumar, Principal Research Scientist, CSIRO; Gavin Rees, Principal Research Scientist, CSIRO; Klaus Joehnk, Principal research scientist, CSIRO, and Tapas Kumar Biswas, Senior scientist, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Climate explained: Sunspots do affect our weather, a bit, but not as much as other things



NASA

Robert McLachlan, Massey University


CC BY-ND

Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.

If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz


Are we headed for a period with lower Solar activity, i.e. sunspots? How long will it last? What happens to our world when global warming and the end of this period converge?

When climate change comes up in conversation, the question of a possible link with the Sun is often raised.

The Sun is a highly active and complicated body. Its behaviour does change over time and this can affect our climate. But these impacts are much smaller than those caused by our burning of fossil fuels and, crucially, they do not build up over time.

The main change in the Sun is an 11-year Solar cycle of high and low activity, which initially revealed itself in a count of sunspots.

One decade of solar activity in one hour.

Sunspots have been observed continuously since 1609, although their cyclical variation was not noticed until much later. At the peak of the cycle, about 0.1% more Solar energy reaches the Earth, which can increase global average temperatures by 0.05-0.1℃.

This is small, but it can be detected in the climate record.

It’s smaller than other known sources of temperature variation, such as volcanoes (for example, the large eruption of Mt Pinatubo, in the Philippines in 1991, cooled Earth by up to 0.4℃ for several years) and the El Niño Southern Oscillation, which causes variations of up to 0.4℃.




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And it’s small compared to human-induced global warming, which has been accumulating at 0.2℃ per decade since 1980.

Although each 11-year Solar cycle is different, and the processes underlying them are not fully understood, overall the cycle has been stable for hundreds of millions of years.

A little ice age

A famous period of low Solar activity, known as the Maunder Minimum, ran from 1645 to 1715. It happened at a similar time as the Little Ice Age in Europe.

But the fall in Solar activity was too small to account for the temperature drop, which has since been attributed to volcanic eruptions.

Solar activity picked up during the 20th century, reaching a peak in the cycle that ran from 1954 to 1964, before falling away to a very weak cycle in 2009-19.

Bear in mind, though, that the climatic difference between a strong and a weak cycle is small.

Forecasting the Solar cycle

Because changes in Solar activity are important to spacecraft and to radio communications, there is a Solar Cycle Prediction Panel who meet to pool the available evidence.

Experts there are currently predicting the next cycle, which will run to 2030, will be similar to the last one. Beyond that, they’re not saying.

If activity picks up again, and its peak happened to coincide with a strong El Niño, we could see a boost in temperatures of 0.3℃ for a year or two. That would be similar to what happened during the El Niño of 2016, which featured record air and sea temperatures, wildfires, rainfall events and bleaching of the Great Barrier Reef.

The extreme weather events of that year provided a glimpse into the future. They gave examples of what even average years will look like after another decade of steadily worsening global warming.

A journey to the Sun

Solar physics is an active area of research. Apart from its importance to us, the Sun is a playground for the high-energy physics of plasmas governed by powerful magnetic, nuclear and fluid-dynamical forces.

The Solar cycle is driven by a dynamo coupling kinetic, magnetic and electrical energy.




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That’s pretty hard to study in the lab, so research proceeds by a combination of observation, mathematical analysis and computer simulation.

Two spacecraft are currently directly observing the Sun: NASA’s Parker Solar Probe (which will eventually approach to just 5% of the Earth-Sun distance), and ESA’s Solar Orbiter, which is en route to observe the Sun’s poles.

Hopefully one day we will have a better picture of the processes involved in sunspots and the Solar cycle.The Conversation

Exploring the 11-year Solar cycle.

Robert McLachlan, Professor in Applied Mathematics, Massey University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

What is a derecho? An atmospheric scientist explains these rare but dangerous storm systems



A derecho moves across central Kansas on July 3, 2005.
Jim Reed/Corbis via Getty Images

Russ Schumacher, Colorado State University

Thunderstorms are common across North America, especially in warm weather months. About 10% of them become severe, meaning they produce hail 1 inch or greater in diameter, winds gusting in excess of 50 knots (57.5 miles per hour), or a tornado.

The U.S. recently has experienced three rarer events: organized lines of thunderstorms with widespread damaging winds, known as derechos.

Derechos occur fairly regularly over large parts of the U.S. each year, most commonly from April through August.
Dennis Cain/NOAA

Derechos occur mainly across the central and eastern U.S., where many locations are affected one to two times per year on average. They can produce significant damage to structures and sometimes cause “blowdowns” of millions of trees. Pennsylvania and New Jersey received the brunt of a derecho on June 3, 2020, that killed four people and left nearly a million without power across the mid-Atlantic region.

In the West, derechos are less common, but Colorado – where I serve as state climatologist and director of the Colorado Climate Center – experienced a rare and powerful derecho on June 6 that generated winds exceeding 100 miles per hour in some locations. And on August 10, a derecho rolled across Iowa, Wisconsin, Illinois and Indiana, generating rare “particularly dangerous situation” warnings from forecasters and registering wind gusts as high as 130 miles per hour.

Derechos have also been observed and analyzed in many other parts of the world, including Europe, Asia and South America. They are an important and active research area in meteorology. Here’s what we know about these unusual storms.

A massive derecho in June 2012 developed in northern Illinois and traveled to the mid-Atlantic coast, killing 22 and causing $4 billion to $5 billion in damages.

Walls of wind

Scientists have long recognized that organized lines of thunderstorms can produce widespread damaging winds. Gustav Hinrichs, a professor at the University of Iowa, analyzed severe winds in the 1870s and 1880s and identified that many destructive storms were produced by straight-line winds rather than by tornadoes, in which winds rotate. Because the word “tornado,” of Spanish origin, was already in common usage, Hinrichs proposed “derecho” – Spanish for “straight ahead” – for damaging windstorms not associated with tornadoes.

In 1987, meteorologists defined what qualified as a derecho. They proposed that for a storm system to be classified as a derecho, it had to produce severe winds – 57.5 mph (26 meters per second) or greater – and those intense winds had to extend over a path at least 250 miles (400 kilometers) long, with no more than three hours separating individual severe wind reports.

Derechos are almost always caused by a type of weather system known as a bow echo, which has the shape of an archer’s bow on radar images. These in turn are a specific type of mesoscale convective system, a term that describes large, organized groupings of storms.

Researchers are studying whether and how climate change is affecting weather hazards from thunderstorms. Although some aspects of mesoscale convective systems, such as the amount of rainfall they produce, are very likely to change with continued warming, it’s not yet clear how future climate change may affect the likelihood or intensity of derechos.

Speeding across the landscape

The term “derecho” vaulted into public awareness in June 2012, when one of the most destructive derechos in U.S. history formed in the Midwest and traveled some 700 miles in 12 hours, eventually making a direct impact on the Washington, D.C. area. This event killed 22 people and caused millions of power outages.

Top: Radar imagery every two hours, from 1600 UTC 29 June to 0400 UTC 30 June 2012, combined to show the progression of a derecho-producing bow echo across the central and eastern US. Bottom: Severe wind reports for the 29-30 June 2012 derecho, colored by wind speed.
Schumacher and Rasmussen, 2020, adapted from Guastini and Bosart 2016, CC BY-ND

Only a few recorded derechos had occurred in the western U.S. prior to June 6, 2020. On that day, a line of strong thunderstorms developed in eastern Utah and western Colorado in the late morning. This was unusual in itself, as storms in this region tend to be less organized and occur later in the day.

The thunderstorms continued to organize and moved northeastward across the Rocky Mountains. This was even more unusual: Derecho-producing lines of storms are driven by a pool of cold air near the ground, which would typically be disrupted by a mountain range as tall as the Rockies. In this case, the line remained organized.

As the line of storms emerged to the east of the mountains, it caused widespread wind damage in the Denver metro area and northeastern Colorado. It then strengthened further as it proceeded north-northeastward across eastern Wyoming, western Nebraska and the Dakotas.

In total there were nearly 350 reports of severe winds, including 44 of 75 miles per hour (about 34 meters per second) or greater. The strongest reported gust was 110 mph at Winter Park ski area in the Colorado Rockies. Of these reports, 95 came from Colorado – by far the most severe wind reports ever from a single thunderstorm system.

Animation showing the development and evolution of the 6-7 June 2020 western derecho. Radar reflectivity is shown in the color shading, with National Weather Service warnings shown in the colored outlines (yellow polygons indicate severe thunderstorm warnings). Source: Iowa Environmental Mesonet.

Coloradans are accustomed to big weather, including strong winds in the mountains and foothills. Some of these winds are generated by flow down mountain slopes, localized thunderstorm microbursts, or even “bomb cyclones.” Western thunderstorms more commonly produce hailstorms and tornadoes, so it was very unusual to have a broad swath of the state experience damaging straight-line winds that extended from west of the Rockies all the way to the Dakotas.

Damage comparable to a hurricane

Derechos are challenging to predict. On days when derechos form, it is often uncertain whether any storms will form at all. But if they do, the chance exists for explosive development of intense winds. Forecasters did not anticipate the historic June 2012 derecho until it was already underway.

For the western derecho on June 6, 2020, outlooks showed an enhanced potential for severe storms in Nebraska and the Dakotas two to three days in advance. However, the outlooks didn’t highlight the potential for destructive winds farther south in Colorado until the morning that the derecho formed.

Once a line of storms has begun to develop, however, the National Weather Service routinely issues highly accurate severe thunderstorm warnings 30 to 60 minutes ahead of the arrival of intense winds, alerting the public to take precautions.

Communities, first responders and utilities may have only a few hours to prepare for an oncoming derecho, so it is important to know how to receive severe thunderstorm warnings, such as TV, radio and smartphone alerts, and to take these warnings seriously. Tornadoes and tornado warnings often get the most attention, but lines of severe thunderstorms can also pack a major punch.

This is an updated version of an article originally published on June 15, 2020.

[Deep knowledge, daily. Sign up for The Conversation’s newsletter.]The Conversation

Russ Schumacher, Associate Professor of Atmospheric Science and Colorado State Climatologist, Colorado State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Storm warning: a new long-range tropical cyclone outlook is set to reduce disaster risk for Pacific Island communities



Photobank.kiev.ua/Shutterstock

Andrew Magee, University of Newcastle; Andrew Lorrey, National Institute of Water and Atmospheric Research, and Anthony Kiem, University of Newcastle

Tropical cyclones are among the most destructive weather systems on Earth, and the Southwest Pacific region is very exposed and vulnerable to these extreme events.

Our latest research, published today in Scientific Reports, presents a new way of predicting the number of tropical cyclones up to four months ahead of the cyclone season, with outlooks tailored for individual island nations and territories.

A new model predicts tropical cyclone counts up to four months in advance.

Tropical cyclones produce extreme winds, large waves and storm surges, intense rainfall and flooding — and account for almost three in four natural disasters across the Southwest Pacific region.

Currently, Southwest Pacific forecasting agencies release a regional tropical cyclone outlook in October, one month ahead of the official start of the cyclone season in November. Our new model offers a long-range warning, issued monthly from July, to give local authorities more time to prepare.

Most importantly, this improvement on existing extreme weather warning systems may save more lives and mitigate damage by providing information up to four months ahead of the cyclone season.

This map shows the expected number of tropical cyclones for the 2020/21 Southwest Pacific cyclone season (November to April).
http://www.tcoutlook.com/latest-outlook, Author provided

Tropical cyclones and climate variability

An average of 11 tropical cyclones form in the Southwest Pacific region each season. Since 1950, tropical cyclones have claimed the lives of nearly 1500 and have affected more than 3 million people.

In 2016, Cyclone Winston, a record-breaking severe category 5 event, was the strongest cyclone to make landfall across Fiji. It killed 44 people, injured 130 and seriously damaged around 40,000 homes. Damages totalled US$1.4 billion — making it the costliest cyclone in Southwest Pacific history.




Read more:
Winston strikes Fiji: your guide to cyclone science


Tropical cyclones are erratic in their severity and the path they travel. Every cyclone season is different. Exactly where and when a tropical cyclone forms is driven by complex interactions between the ocean and the atmosphere, including the El Niño-Southern Oscillation, sea surface temperatures in the Indian Ocean, and many other climate influences.

Capturing changes in all of these climate influences simultaneously is key to producing more accurate tropical cyclone outlooks. Our new tool, the Long-Range Tropical Cyclone Outlook for the Southwest Pacific (TCO-SP), will assist forecasters and help local authorities to prepare for the coming season’s cyclone activity.

This map shows the probability of below or above-average tropical cyclones for the 2020/21 Southwest Pacific cyclone season.
http://www.tcoutlook.com/latest-outlook, Author provided

According to the latest long-range sea surface temperature outlook, there is a 79% chance that La Niña conditions could develop before the start of the 2020-21 Southwest Pacific cyclone season. La Niña conditions typically mean the risk of tropical cyclone activity is elevated for island nations in the western part of the region (New Caledonia, Solomon Islands and Vanuatu) and reduced for nations in the east (French Polynesia and the Cook Islands). But there are exceptions, particularly when certain climate influences like the Indian Ocean Dipole occur with La Niña events.




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Improving existing tropical cyclone guidance

Current guidance on tropical cyclones in the Southwest Pacific region is produced by the National Institute of Water and Atmospheric Research, the Australian Bureau of Meteorology and the Fiji Meteorological Service. Each of these organisations uses a different method and considers different indices to capture ocean-atmosphere variability associated with the El Niño-Southern Oscillation.

Our research adds to the existing methods used by those agencies, but also considers other climate drivers known to influence tropical cyclone activity. In total, 12 separate outlooks are produced for individual nations and territories including Fiji, Solomon Islands, New Caledonia, Vanuatu, Papua New Guinea and Tonga.

Other locations are grouped into sub-regional models, and we also provide outlooks for New Zealand because of the important impacts there from ex-tropical cyclones.

Our long-range outlook is a statistical model, trained on historical relationships between ocean-atmosphere processes and the number of tropical cyclones per season. For each target location, hundreds of unique model combinations are tested. The one that performs best in capturing historical tropical cyclone counts is selected to make the prediction for the coming season.

At the start of each monthly outlook, the model retrains itself, taking the most recent changes in ocean temperature and atmospheric variability and attributes of tropical cyclones from the previous season into account.

Both deterministic (tropical cyclone numbers) and probabilistic (the chance of below, normal or above average tropical cyclone activity) outlooks are updated every month between July and January and are freely available.The Conversation

Andrew Magee, Postdoctoral Researcher, University of Newcastle; Andrew Lorrey, Principal Scientist & Programme Leader of Climate Observations and Processes, National Institute of Water and Atmospheric Research, and Anthony Kiem, Associate Professor – Hydroclimatology, University of Newcastle

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Extreme heat and rain: thousands of weather stations show there’s now more of both, for longer



ChameleonsEye/Shutterstock

Jim Salinger, University of Tasmania and Lisa Alexander, UNSW

A major global update based on data from more than 36,000 weather stations around the world confirms that, as the planet continues to warm, extreme weather events such as heatwaves and heavy rainfall are now more frequent, more intense, and longer.

The research is based on a dataset known as HadEX and analyses 29 indices of weather extremes, including the number of days above 25℃ or below 0℃, and consecutive dry days with less than 1mm of rain. This latest update compares the three decades between 1981 and 2010 to the 30 years prior, between 1951 and 1980.

Globally, the clearest index shows an increase in the number of above-average warm days.


Author provided

For Australia, the team found a country-wide increase in warm temperature extremes and heatwaves and a decrease in cold temperature extremes such as the coldest nights. Broadly speaking, rainfall extremes have increased in the west and decreased in the east, but trends vary by season.

In New Zealand, temperate regions experience significantly more summer days and northern parts of the country are now frost-free.




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Extreme temperatures

Unusually warm days are becoming more common throughout Australia. When we compare 1981-2010 with 1951-80, the increase is substantial: more than 20 days per year in the far north of Australia, and at least 10 days per year in most areas apart from the south coast. The increase occurs in all seasons but is largest in spring.

This increase in temperature extremes can have devastating impacts for human health, particularly for older people and those with pre-existing medical conditions. Excessive heat is not only an issue for people living in cities but also for rural communities that have already been exposed to days with temperatures above 50℃.

New Zealanders are also experiencing more days with temperatures of 25℃ or more. The climate stations show the frequency of unusually warm days has increased from 8% to 12% from 1950 to 2018, with an average of 19 to 24 days a year above 25℃ across the country. Unusually warm days, defined as days in the top 10% of historic records for the time of year, are also becoming more common in both countries.

During the summers of 2017-18 and 2018-19, marine heatwaves delivered 32 and 26 (respectively) days above 25℃ nationwide in New Zealand, well above the average of 20 days. This led to accelerated glacial melting in the Southern Alps and major disruption to marine ecosystems, with die-offs of bull kelp around the South Island coast and salmon in aquaculture farms in the Marlborough Sounds.




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Farmed fish dying, grape harvest weeks early – just some of the effects of last summer’s heatwave in NZ


More heat, more rain, less frost

In many parts of New Zealand, cold extremes are changing faster than warm extremes.

Between 1950 and 2018, frost days (days below 0℃) have declined across New Zealand, particularly in northern parts of the country which has now become frost-free, enabling farmers to grow subtropical pasture grasses. At the same time, crops that require winter frosts to set fruit are no longer successful, or can only be grown with chemical treatments (currently under review) that simulate winter chilling.

Across New Zealand, the heat available for crop growth during the growing season is increasing, which means wine growers have to shift varieties further south.

In Australia, the situation is more complicated. In many parts of northern and eastern Australia, there has also been a large decrease in the number of cold nights. But in parts of southeast and southwest Australia, frost frequency has stabilised, or even increased in places, since the 1980s.

These areas have seen a large decrease in winter rainfall in recent decades. The higher number of dry, clear nights in winter, favourable for frost formation, has cancelled out the broader warming trend.




Read more:
Droughts & flooding rains: what is due to climate change?


In Australia, extreme rainfall has become more frequent in many parts of northern and western Australia, especially the northwest, which has become wetter since the 1960s. In eastern and southern Australia the picture is more mixed, with little change in the number of days with 10mm or more of rain, even in those regions where total rainfall has declined.

In New Zealand, more extremely wet days contribute towards the annual rainfall total in the east of the North Island, with a smaller increase in the west and south of the South Island. For Australia, there are significant drying trends in parts of the southwest and northeast, but little change elsewhere.

Extremes of temperature and precipitation can have dramatic effects, as seen during two marine heatwaves in New Zealand and the hottest, driest year in Australia during 2019.The Conversation

Jim Salinger, Honorary Associate, Tasmanian Institute for Agriculture, University of Tasmania and Lisa Alexander, Chief Investigator ARC Centre of Excellence for Climate System Science and Associate Professor Climate Change Research Centre, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How drought-breaking rains transformed these critically endangered woodlands into a flower-filled vista



Wildflowers blooming in box gum grassy woodland
Jacqui Stol, Author provided

Jacqui Stol, CSIRO; Annie Kelly, and Suzanne Prober, CSIRO

In box gum grassy woodlands, widely spaced eucalypts tower over carpets of wildflowers, lush native grasses and groves of flowering wattles. It’s no wonder some early landscape paintings depicting Australian farm life are inspired by this ecosystem.

But box gum grassy woodlands are critically endangered. These woodlands grow on highly productive agricultural country, from southern Queensland, along inland slopes and tablelands, into Victoria.

Many are degraded or cleared for farming. As a result, less than 5% of the woodlands remain in good condition. What remains often grows on private land such as farms, and public lands such as cemeteries or travelling stock routes.




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Very little is protected in public conservation reserves. And the recent drought and record breaking heat caused these woodlands to stop growing and flowering.

But after Queensland’s recent drought-breaking rain earlier this year, we surveyed private farmland and found many dried-out woodlands in the northernmost areas transformed into flower-filled, park-like landscapes.

And landholders even came across rarely seen marsupials, such as the southern spotted-tail quoll.

Native yellow wildflowers called ‘scaly buttons’ bloom on a stewardship site.
Jacqui Stol, Author provided

Huge increase in plant diversity

These surveys were part of the Australian government’s Environmental Stewardship Program, a long-term cooperative conservation model with private landholders. It started in 2007 and will run for 19 years.

We found huge increases in previously declining native wildflowers and grasses on the private farmland. Many trees assumed to be dying began resprouting, such as McKie’s stringybark (Eucalyptus mckieana), which is listed as a vulnerable species.

This newfound plant diversity is the result of seeds and tubers (underground storage organs providing energy and nutrients for regrowth) lying dormant in the soil after wildflowers bloomed in earlier seasons. The dormant seeds and tubers were ready to spring into life with the right seasonal conditions.

For example, Queensland Herbarium surveys early last year, during the drought, looked at a 20 metre by 20 metre plot and found only six native grass and wildflower species on one property. After this year’s rain, we found 59 species in the same plot, including many species of perennial grass (three species jumped to 20 species post rain), native bluebells and many species of native daisies.




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On another property with only 11 recorded species, more than 60 species sprouted after the extensive rains.

In areas where grazing and farming continued as normal (the paired “control” sites), the plots had only around half the number of plant species as areas managed for conservation.

Spotting rare marsupials

Landowners also reported several unusual sightings of animals on their farms after the rains. Stewardship program surveyors later identified them as two species of rare and endangered native carnivorous marsupials: the southern spotted-tailed quoll (mainland Australia’s largest carnivorous marsupial) and the brush-tailed phascogale.

The population status of both these species in southern Queensland is unknown. The brush-tailed phascogale is elusive and rarely detected, while the southern spotted-tailed quolls are listed as endangered under federal legislation.

Until those sightings, there were no recent records of southern spotted-tailed quolls in the local area.

A spotted tailed quoll caught in a camera trap.
Sean Fitzgibbon, Author provided

These unusual wildlife sightings are valuable for monitoring and evaluation. They tell us what’s thriving, declining or surviving, compared to the first surveys for the stewardship program ten years ago.

Sightings are also a promising signal for the improving condition of the property and its surrounding landscape.

Changing farm habits

More than 200 farmers signed up to the stewardship program for the conservation and management of nationally threatened ecological communities on private lands. Most have said they’re keen to continue the partnership.

The landholders are funded to manage their farms as part of the stewardship program in ways that will help the woodlands recover, and help reverse declines in biodiversity.

For example, by changing the number of livestock grazing at any one time, and shortening their grazing time, many of the grazing-sensitive wildflowers have a better chance to germinate, grow, flower and produce seeds in the right seasonal conditions.




Read more:
‘Plant blindness’ is obscuring the extinction crisis for non-animal species


They can also manage weeds, and not remove fallen timber or loose rocks (bushrock). Fallen timber and rocks protect grazing-sensitive plants and provide habitat for birds, reptiles and invertebrates foraging on the ground.

Cautious optimism

So can we be optimistic for the future of wildlife and wildflowers of the box gum grassy woodlands? Yes, cautiously so.

Landholders are learning more about how best to manage biodiversity on their farms, but ecological recovery can take time. In any case, we’ve discovered how resilient our flora and fauna can be in the face of severe drought when given the opportunity to grow and flourish.

The rare hooded robin has also been recorded on stewardship sites during surveys.
Micah Davies, Author provided

Climate change is bringing more extreme weather events. Last year was the warmest on record and the nation has been gripped by severe, protracted drought. There’s only so much pressure our iconic wildlife and wildflowers can take before they cross ecological thresholds that are difficult to bounce back from.

More government programs like this, and greater understanding and collaboration between scientists and farmers, create a tremendous opportunity to keep changing that trajectory for the better.The Conversation

Jacqui Stol, Senior Experimental Scientist, Ecologist, CSIRO Land and Water, CSIRO; Annie Kelly, Senior Ecologist, and Suzanne Prober, Senior Principal Research Scientist, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

We dug up Australian weather records back to 1838 and found snow is falling less often



State Library of South Australia

Joelle Gergis, Australian National University and Linden Ashcroft, University of Melbourne

As we slowly emerge from lockdown, local adventures are high on people’s wish lists. You may be planning a trip to the ski fields, or even the nearby hills to revel in the white stuff that occasionally falls around our southern cities after an icy winter blast.

Our new research explores these low-elevation snowfall events. We pieced together weather records back to 1838 to create Australia’s longest analysis of daily temperature extremes and their impacts on society.

These historical records can tell us a lot about Australia’s pre-industrial climate, before the large-scale burning of fossil fuels tainted global temperature records.

They also help provide a longer context to evaluate more recent temperature extremes.

We found snow was once a regular feature of the southern Australian climate. But as Australia continues to warm under climate change, cold extremes are becoming less frequent and heatwaves more common.

Heatwaves in Adelaide are becoming more common.
David Mariuz/AAP

Extending Australia’s climate record

Data used by the Bureau of Meteorology to study long-term weather and climate dates back to the early 1900s. This is when good coverage of weather stations across the country began, and observations were taken in a standard way.

But many older weather records exist in national and state archives and libraries, as well as local historical societies around the country.




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We analysed daily weather records from the coastal city of Adelaide and surrounding areas, including the Adelaide Hills, back to 1838. Adelaide is the Australian city worst affected by heatwaves, and the capital of our nation’s driest state, South Australia.

To crosscheck the heatwaves and cold extremes identified in our historical temperature observations, we also looked at newspaper accounts, model simulations of past weather patterns, and palaeoclimate records.

The agreement was remarkable. It demonstrates the value of historical records for improving our estimation of future climate change risk.

Weather journal of Adelaide’s historical climate held by the National Archives of Australia.
National Archives of Australia

‘Limpness to all mankind’

While most other historical climate studies have looked at annual or monthly values, the new record enabled us to look at daily extremes.

This is important, because global temperature increases are most clearly detected in changes to extreme events such as heatwaves. Although these events may only last a few days, they have very real impacts on human health, agriculture and infrastructure.

Our analysis focused on the previously undescribed period before 1910, to extend the Bureau of Meteorology’s official record as far as possible.

Using temperature observations, we identified 34 historical heatwaves and 81 cold events in Adelaide from 1838–1910. We found more than twice as many of these “snow days” by conducting an independent analysis of snowfall accounts in historical documents.

Almost all the events in the temperature observations were supported by newspaper reports. This demonstrated our method can accurately identify historical temperature extremes.

For example, an outbreak of cold air on June 22, 1908, delivered widespread snow across the hills surrounding Adelaide. The Express and Telegraph newspaper reported:

Many people made a special journey from Adelaide by train, carriage, or motor to revel in the unwonted delight of gazing on such a wide expanse of real snow, and all who did so felt that their trouble was amply rewarded by the panorama of loveliness spread out before their enraptured eyes.

Snowballing at Mount Lofty 29 August 1905.
Source: State Library of South Australia

From December 26-30, 1897, Adelaide was gripped by a heatwave that produced five days above 40℃. Newspapers reported heat-related deaths, agricultural damage, animals dying in the zoo, bushfires and even “burning hot pavements scorching the soles of people’s shoes”. As The Advertiser reported:

When the mercury reaches its “century” (100℉ or 37.6℃) there must be a really uncomfortable experience for everyone. One such day can be struggled with; but six of them in a fortnight, three in succession — that is a thing to bring limpness to all mankind.

On December 31, 1897, the South Australian Register wrote prophetically of future Australian summers:

May Heaven preserve us from being here when the “scorchers” try and add a few degrees to the total.

Newspaper account of a deadly heatwave published in the South Australian Register on Friday 31 December 1897.
National Library of Australia

A longer view

While Australia has a long history of hot and cold extremes, our extended analysis shows that their frequency and intensity is changing.

The quality of the very early part of the record is still uncertain, so the information from the 1830s and 1840s must be treated with caution. That said, there is excellent agreement with newspaper and other historical records.

Our research suggests low-elevation snow events around Adelaide have become less common over the past 180 years. This can be seen in both temperature observations and independent newspaper accounts. For example, snowfall was exceptionally high in the 1900s and 1910s — more than four times more frequent than other decades.




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We also found heatwaves are becoming more frequent in Adelaide. The decade 2010–19 has the highest count of heatwaves of any decade in the record. Although recent heatwaves are not significantly longer than those of the past, our analysis showed heatwaves of up to ten days are possible.

Previous Australian studies have identified an increase in extreme heat and a corresponding decrease in cold events. However, this is the longest analysis in Australia, and the first to systematically combine instrumental and documentary information.

Number of heatwaves identified in Adelaide from January 1838 to August 2019. No digitised temperature observations are available from 1 January 1848 – 1 November 1856, so these decades are shown in lighter shades.
Author supplied
Number of extreme cold days identified in Adelaide from January 1838 to August 2019. No digitised temperature observations are currently available from 1 January 1848 – 1 November 1856, so these decades are shaded grey.
Author supplied

Learning from the past

This study shows we can use historical weather records to get a better picture of Australia’s long-term weather and climate history. By using different sources of information, we can piece together the significant events in our climate history with greater certainty.

Historical records tell us about more than just exciting day trips of the past. They also hold the key to understanding impacts of extreme events, such as heat-related deaths or agricultural damage, in the future.

A better understanding of these pre-industrial extremes will help emergency management services better adapt to increased climate risk, as Australia continues to warm.




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The Conversation


Joelle Gergis, Senior Lecturer in Climate Science, Australian National University and Linden Ashcroft, Lecturer in climate science and science communication, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

After a storm, microplastics in Sydney’s Cooks River increased 40 fold



A litter trap in Cook’s River.
James HItchcock, Author provided

James Hitchcock, University of Canberra

Each year the ocean is inundated with 4.8 to 12.7 million tonnes of plastic washed in from land. A big proportion of this plastic is between 0.001 to 5 millimetres, and called “microplastic”.

But what happens during a storm, when lashings of rain funnel even more water from urban land into waterways? To date, no one has studied just how important storm events may be in polluting waterways with microplastics.




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So to find out, I studied my local waterway in Sydney, the Cooks River estuary. I headed out daily to measure how many microplastics were in the water, before, during, and after a major storm event in October, 2018.

The results, published on Wednesday, were startling. Microplastic particles in the river had increased more than 40 fold from the storm.

Particles of plastic found in rivers. They may be tiny, but they’re devastating to wildlife in waterways.
Author provided

To inner west Sydneysiders, the Cooks River is known to be particularly polluted. But it’s largely similar to many urban catchments around the world.

If the relationship between storm events and microplastic I found in the Cooks River holds for other urban rivers, then the concentrations of microplastics we’re exposing aquatic animals to is far higher than previously thought.

14 million plastic particles

They may be tiny, but microplastics are a major concern for aquatic life and food webs. Animals such as small fish and zooplankton directly consume the particles, and ingesting microplastics has the potential to slow growth, interfere with reproduction, and cause death.

Determining exactly how much microplastic enters rivers during storms required the rather unglamorous task of standing in the rain to collect water samples, while watching streams of unwanted debris float by (highlights included a fire extinguisher, a two-piece suit, and a litany of tennis balls).

Back in the laboratory, a multi-stage process is used to separate microplastics. This includes floating, filtering, and using strong chemical solutions to dissolve non-plastic items, before identification and counting with specialised microscopes.

Litter caught in a trap in Cooks River. These traps aren’t effective at catching microplastic.
Author provided

In the days before the October 2018 storm, there were 0.4 particles of microplastic per litre of water in the Cooks River. That jumped to 17.4 microplastics per litre after the storm.

Overall, that number averages to a total of 13.8 million microplastic particles floating around in the Cooks River estuary in the days after the storm.




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In other urban waterways around the world scientists have found similarly high numbers of microplastic.

For example in China’s Pearl River, microplastic averages 19.9 particles per litre. In the Mississippi River in the US, microplastic ranges from 28 to 60 particles per litre.

Where do microplastics come from?

We know runoff during storms is one of the main ways pollutants such as sediments and heavy metals end up in waterways. But not much is known about how microplastic gets there.

However think about your street. Wherever you see litter, there are also probably microplastics you cannot see that will eventually work their way into waterways when it rains.




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Many other sources of microplastics are less obvious. Car tyres, for example, which typically contain more plastic than rubber, are a major source of microplastics in our waterways. When your tyres lose tread over time, microscopic tyre fragments are left on roads.

Did you know your car tyres can be a major source of microplastic pollution?
Shutterstock

Microplastics may even build up on roads and rooftops from atmospheric deposition. Everyday, lightweight microplastics such as microfibres from synthetic clothing are carried in the wind, settling and accumulating before they’re washed into rivers and streams.

What’s more, during storms wastewater systems may overflow, contaminating waterways. Along with sewage, this can include high concentrations of synthetic microfibers from household washing machines.

And in regional areas, microplastics may be washing in from agricultural soils. Sewage sludge is often applied to soils as it is rich in nutrients, but the same sludge is also rich in microplastics.

What can be done?

There are many ways to mitigate the negative effects of stormwater on waterways.

Screens, traps, and booms can be fitted to outlets and rivers and catch large pieces of litter such as bottles and packaging. But how useful these approaches are for microplastics is unknown.

Raingardens and retention ponds are used to catch and slow stormwater down, allowing pollutants to drop to bottom rather than being transported into rivers. Artificial wetlands work in similar ways, diverting stormwater to allow natural processes to remove toxins from the water.

Almost 14 million plastic particles were floating in Cooks River after a storm two years ago.
Shutterstock

But while mitigating the effects of stormwater carrying microplastics is important, the only way we’ll truly stop this pollution is to reduce our reliance on plastic. We must develop policies to reduce and regulate how much plastic material is produced and sold.

Plastic is ubiquitous, and its production around the world hasn’t slowed, reaching 359 million tonnes each year. Many countries now have or plan to introduce laws regulating the sale or production of some items such as plastic bags, single-use plastics and microbeads in cleaning products.




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In Australia, most state governments have committed to banning plastic bags, but there are still no laws banning the use of microplastics in cleaning or cosmetic products, or single-use plastics.

We’ve made a good start, but we’ll need deeper changes to what we produce and consume to stem the tide of microplastics in our waterways.The Conversation

James Hitchcock, Post-Doctoral Research Fellow, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Why drought-busting rain depends on the tropical oceans


Andrew King, University of Melbourne; Andy Pitman, UNSW; Anna Ukkola, Australian National University; Ben Henley, University of Melbourne, and Josephine Brown, University of Melbourne

Recent helpful rains dampened fire grounds and gave many farmers a reason to cheer. But much of southeast Australia remains in severe drought.

Australia is no stranger to drought, but the current one stands out when looking at rainfall records over the past 120 years. This drought has been marked by three consecutive extremely dry winters in the Murray-Darling basin, which rank in the driest 10% of winters since 1900.

Despite recent rainfall the southeast of Australia remains in the grip of a multi-year drought.
Bureau of Meteorology

So what’s going on?

There has been much discussion on whether human-caused climate change is to blame. Our new study explores Australian droughts through a different lens.




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Rather than focusing on what’s causing the dry conditions, we investigated why it’s been such a long time since we had widespread drought-breaking rain. And it’s got a lot to do with how the temperature varies in the Pacific and Indian Ocean.

Our findings suggest that while climate change does contribute to drought, blame can predominately be pointed at the absence of the Pacific Ocean’s La Niña and the negative Indian Ocean Dipole – climate drivers responsible for bringing wetter weather.

Understanding the Indian Ocean Dipole.

What’s the Indian Ocean Dipole?

As you may already know, the Pacific Ocean influences eastern Australia’s climate through El Niño conditions (associated with drier weather) and La Niña conditions (associated with wetter weather).

The lesser known cousin of El Niño and La Niña across the Indian Ocean is called the Indian Ocean Dipole. This refers to the difference in ocean temperature between the eastern and western sides of the Indian Ocean. It modulates winter and springtime rainfall in southeastern Australia.




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When the Indian Ocean Dipole is “negative”, there are warmer ocean temperatures in the east Indian Ocean, and we see more rain over much of Australia. The opposite is true for “positive” Indian Ocean Dipole events, which bring less rain.

The Murray-Darling Basin experiences high rainfall variability, with decade-long droughts common since observations began. The graph shows seasonal rainfall anomalies from a 1961-1990 average with major droughts marked.
Author provided

What does it mean for the drought?

When the drought started to take hold in 2017 and 2018, we didn’t experience an El Niño or strongly positive Indian Ocean Dipole event. These are two dry-weather conditions we might expect to see at the start of a drought.

Rather, conditions in the Pacific and Indian Oceans were near neutral, with little to suggest a drought would develop.

So why are we in severe, prolonged drought?

The problem is we haven’t had either a La Niña or a negative Indian Ocean Dipole event since winter 2016. Our study shows the lack of these events helps explain why eastern Australia is in drought.

For the southeast of Australia in particular, La Niña or negative Indian Ocean Dipole events provide the atmosphere with suitable conditions for persistent and widespread rainfall to occur. So while neither La Niña or a negative Indian Ocean Dipole guarantee heavy rainfall, they do increase the chances.

What about climate change?

While climate drivers are predominately causing this drought, climate change also contributes, though more work is needed to understand what role it specifically plays.

Drought is more complicated and multidimensional than simply “not much rain for a long time”. It can be measured with a raft of metrics beyond rainfall patterns, including metrics that look at humidity levels and evaporation rates.

What we do know is that climate change can exacerbate some of these metrics, which, in turn, can affect drought.




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Climate change might also influence climate drivers, though right now it’s hard to tell how. A 2015 study suggests that under climate change, La Niña events will become more extreme. Another study from earlier this month suggests climate change is driving more positive Indian Ocean Dipole events, bringing even more drought.

Unfortunately, regional-scale projections from climate models aren’t perfect and we can’t be sure how the ocean patterns that increase the chances of drought-breaking rains will change under global warming. What is clear is there’s a risk they will change, and strongly affect our rainfall.

Putting the drought in context

Long periods when a La Niña or a negative Indian Ocean Dipole event were absent characterised Australia’s past droughts. This includes two periods of more than three years that brought us the Second World War drought and the Millennium drought.

The longer the time without a La Niña or negative Indian Ocean Dipole event, the more likely the Murray-Darling Basin is in drought.

In the above graph, the longer each line continues before stopping, the longer the time since a La Niña or negative Indian Ocean Dipole event occurred. The lower the lines travel, the less rainfall was received in the Murray Darling basin during this period. This lets us compare the current drought to previous droughts.

During the current drought (black line) we see how the rainfall deficit continues for several years, almost identically to how the Millennium drought played out.

But then the deficit increases strongly in late 2019, when we had a strongly positive Indian Ocean Dipole.

So when will this drought break?

This is a hard question to answer. While recent rains have been helpful, we’ve developed a long-term rainfall deficit in the Murray-Darling Basin and elsewhere that will be hard to recover from without either a La Niña or negative Indian Ocean Dipole event.




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The most recent seasonal forecasts don’t predict either a negative Indian Ocean Dipole or La Niña event forming in the next three months. However, accurate forecasts are difficult at this time of year as we approach the “autumn predictability barrier”.

This means, for the coming months, the drought probably won’t break. After that, it’s anyone’s guess. We can only hope conditions improve.The Conversation

Andrew King, ARC DECRA fellow, University of Melbourne; Andy Pitman, Director of the ARC Centre of Excellence for Climate System Science, UNSW; Anna Ukkola, Research Fellow, Australian National University; Ben Henley, Research Fellow in Climate and Water Resources, University of Melbourne, and Josephine Brown, Lecturer, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How weather radar can keep tabs on the elusive magpie goose


Magpie Geese taking off from a mango orchard in the Northern Territory.
Rebecca Rogers, Author provided

Rebecca Rogers, Charles Darwin University

You’re probably familiar with weather radar that shows bands of rain blowing in to ruin your plans for the day, or the ominous swirling pattern of a cyclone.

But rain isn’t the only thing that shows up on the radar screen. Anything moving through the sky will – like a large group of birds in flight.

Ecologists have begun to realise that weather radar data have huge potential to reveal the movements of flying animals all over the country.

At the forefront of this research is the magpie goose, an occasionally controversial waterbird prized by some and detested by others.

It’s a lovely day in northern Australia, and you are a magpie goose. These waterbirds are an ideal test case for weather-radar tracking.
Shutterstock

Chasing angels

To understand how we got to this point, first we need to go back 80 years. Prior to World War II, engineers were racing to improve radar systems to detect enemy aircraft when they noticed strange unexplained rings on their screens that they called angels.

Some of these angels, they realised later, were caused by groups of birds and bats taking off and flying through the radar beam. Since this discovery, there has been a steady increase in researchers using weather radar to understand how and why animals move through the air.

How weather radar works

Radar works by sending out a sweeping beam of radio waves and listening for echoes. It processes these echoes to map the positions of objects around it.

With weather radar, the radar beam won’t only bounce off raindrops – it will also reflect back from birds. Some weather radars send out these pulses at a precise frequency, which allows them to use the Doppler effect to determine how fast objects are moving towards or away from the radar.

Meteorologists have ways to filter out clutter caused by flying animals, so they can see where it is raining. Ecologists are doing the reverse, filtering out rain from the raw data collected by weather radars in order to track the movements of birds, bats and even insect swarms.

Weather radars cover a good part of the Australian continent, which makes them very useful for tracking birds.
Rogers et al. (2019) – Austral Ecology

Most weather radars can give us a three-dimensional picture of what is happening in the air every 5–10 minutes. In Australia the data is archived for years and even decades in some places, and it is all available free of charge for researchers. This means we can not only understand how animals are using the airspace now, but also how these movement patterns may have changed over time.

Is it a bird? Is it a plane?

So how do we actually tell whether those pixels on the screen are caused by rain, birds or something less common like bushfire smoke?

This is where things can get a bit more tricky. For some cases, like tracking bats coming out of a cave or roost tree, the job for the ecologist is fairly simple. For roosting species like these, we often observed very characteristic rings on the radar similar to the angels described by those early radar engineers. Examples of the rings can be found all over Australia caused by flying foxes.

Flying animals leave traces in weather radar images. The image at left shows an ‘angel echo’ caused by flying foxes coming out of a roost in NSW, while the one on the right reveals ‘blooms’ of activity on the Darwin radar, likely to be caused by magpie geese and other waterbirds taking off for their morning feeding flights.
Rogers et al. (2019) – Austral Ecology

For broadly distributed species, like the magpie geese found all across northern Australia, the picture is not so easy to interpret. These animals tend to produce patterns best described as blooms of activity: they appear across the radar image, spreading out and then blending together like a bunch of flowers blooming all at once.

These patterns can look similar to rain clouds to the untrained eye. However, with some understanding of how the radar works and the behaviour of the birds – like when they are active or how high they fly – we can quickly begin to narrow down what might be causing different patterns on radar images.

Why track magpie geese?

Magpie geese cross paths with humans in many different ways.

They are hunted by Indigenous people for food, they are considered a pest for mango farmers and a strike risk for planes, and they could be vectors for disease.

Tracking magpie geese can help us better understand this native species and ensure it thrives long into the future.




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Like many waterbirds, magpie geese have distinct daily patterns of movement, which makes them ideal candidates for trialling the use of weather radar to track Australian birds.

In Darwin, blooms of activity occur all over the radar in the morning and evening when magpie geese are taking off from wetlands and mango orchards for their daily feeding flights.

By using GPS tracking collars and annual survey data, we are starting to see how these patterns in the radar data correspond to real behaviour. These results are showing how weather radar could be repurposed to track the movement of magpie geese – and after that, many other kinds of birds in Australia.The Conversation

Rebecca Rogers, PhD Candidate, Charles Darwin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.