Last year was a time of exceptional weather and record-breaking heat according to the Bureau of Meteorology’s annual climate statement, which was released last night.
The Bureau issued four Special Climate Statements relating to “extreme” and “abnormal” heat, and reported a number of broken climate records.
One of the headline stories for the year was drought across eastern Australia — centred on New South Wales, but also affecting Victoria, eastern South Australia and southern Queensland.
With the whole of NSW declared in drought during the latter half of 2018, this drought will be recorded as one of the more significant in Australia’s history, ranking alongside the Millennium, 1960s, World War Two and Federation Droughts. Of those historic droughts, only the Millennium Drought saw similar, accompanying high temperatures.
The below-average rainfall has persisted for around two years across much of NSW and adjacent regions. The drought conditions were particularly severe in the recent spring period, with low rainfall, persistently high temperatures, and record high evaporation.
This exceptionally dry period was influenced by sea surface temperatures to the west of the continent. Perhaps fortuitously, a developing El Niño in the Pacific Ocean failed to mature in the second half of the year. An El Niño would have typically exerted a further drying influence on eastern Australia.
The dry conditions in eastern states were severe enough to see Australia record its lowest September rainfall on record, and the second-lowest on record for any month — behind April 1902, during the prolonged Federation Drought. Over 2018, Australia’s annual rainfall was 11% below average, and the lowest recorded since 2005, during the Millennium Drought.
In contrast, above-average rainfall was recorded across parts of the tropical north, and most significantly in the Kimberley, consistent with recent trends of increasing rainfall in that region.
The drought conditions were exacerbated by record or near-record temperatures across many parts of the country. It was Australia’s third warmest year on record, behind 2013 and 2005. Daytime maximum temperatures were the warmest on record for NSW and Victoria, and second-warmest for South Australia, the Northern Territory and Australia as a whole.
Persistent dry conditions through winter are typically associated with low soil moisture and heatwaves in the following spring and summer, and 2018 followed this pattern — with the added contribution of a warming climate.
The year ended with some record-breaking heat events. Perhaps the most significant of these was the extreme heat along the central and northern Queensland coast in late November and early December, which saw maximum daytime temperatures of 42.6 °C in Cairns and 44.9 °C in Proserpine on the 26th of November.
These temperatures, combined with persistent dry conditions in the preceding months, saw catastrophic fire weather and bushfires along 600km of the Queensland coast, an event that fire agencies have called unprecedented for the state.
The year ended with a burst of heat over the Christmas-New Year period, with temperatures at least 10 degrees warmer than average across southern South Australia, most of Victoria and southern NSW, leading to Australia’s warmest December on record.
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Many Australians will take a trip to one of our national parks over the holidays. In New South Wales alone, there are more than 51 million visits to national parks each year. Few if any of us would expect not to make it out of one alive.
But national parks claim lives around the world every year. In the United States, an average of 160 visitors each year die in a national park. Australia’s numbers are unsurprisingly smaller – there have been 13 deaths in national parks since 2013 – but the common theme is that these fatalities are usually avoidable.
Wherever death and injury are avoidable, it pays to alert people to the dangers. In Australia the main risks – falling off cliffs and waterfalls, deadly snakebites, getting lost – can all be reduced by one crucial piece of advice: stick to the path.
It sounds simple enough. But in fact, visitors failing to heed advice about walking trails is a significant problem for national park managers. Venturing off-trail poses significant danger to visitors, and puts unnecessary strain on emergency services and police.
Our 2017 study was the first to gather some hard numbers on the reasons why people tend to disobey the signs. We surveyed 325 visitors at Blue Mountains National Park on their attitudes to off-trail walking.
So, what’s behind our compulsion to get off the beaten track? First, 30% of respondents told us that off-trail walking can result in a shorter or easier walking route, whereas 20% said straying from the path can afford a closer look at nature.
Second, visitors are heavily influenced by other visitors and friends – the “monkey see, monkey do” effect. They are much more likely to leave the track if they see someone else do it first.
Third, in the absence of a handy toilet, many visitors venture off-trail for a private “comfort break”.
Finally, visitors rely heavily on signage to help them stay on the designated trail. Some 13% of our survey respondents said they would venture off-trail if there was a lack of adequate signs.
What might change our behaviour?
There are several tactics park authorities can use to reduce off-trail walking at national parks. They can use direct management techniques such as capping site capacity to avoid congestion – basically, regulating the maximum number of walkers in a given area, so the paths don’t feel too congested. They may consider zoning orders to permit or limit certain events to control capacity.
Ropes or low barriers along the walking trail can give a clear indication of the trail’s boundary. Of course, there is a fine balance between building structural barriers and maintaining the feeling of natural wilderness in a park.
Social media marketing might also work well. Suggested slogans such as “A true mate sticks to the trail” or “Be safe and stay on the trail with your mates” might help influence visitors’ behaviour. Park visitors are ever more connected to social media – Parks Australia’s social media channels reach an estimated 30 million people.
Signs should also let walkers know exactly what they are getting themselves into, by posting clearly the length and typical duration of walking tracks, and the distance to popular destinations such as lookout points. These signs should be posted both at the beginning of trails at at intervals along it, particularly at junctions or river crossings.
When it comes to our national parks it’s best to assume that, as with most things in life, humans will look for alternatives to what is expected. It’s human nature to want to bend the rules in what we might wrongly think is a harmless way.
Bushwalking in a national park is a great way to spend some time this summer. But when going off-trail could turn a tranquil walk into a deadly accident, it pays to stay on the beaten track.
The year gets off to a bang with the Quadrantids, the first of the annual big three meteor showers. Active while the Moon is new, it gives northern hemisphere observers a show to enjoy during the cold nights of winter. Sadly, the shower is not visible from southern skies.
The other two members of the big three — the Perseids and Geminids — are not so fortunate this year, with moonlight set to interfere and reduce their spectacle.
So, with that in mind, where and when should you observe to make the best of 2019’s meteoric offerings? Here we present the likely highlights for this year – the showers most likely to put on a good show.
We provide details of the full forecast activity period for each shower, and the forecast time of maximum. We also give sky charts, showing you where best to look, and give the theoretical peak rates that could be seen under ideal observing conditions – a number known as the Zenithal Hourly Rate, or ZHR.
It is important to note that the ZHR is the theoretical maximum number of meteors you would expect to see per hour for a given shower, unless it were to catch us by surprise with an unexpected outburst!
In reality, the rates you observe will be lower than the ZHR – but the clearer and darker your skies, and the higher the shower’s radiant in the sky, the closer you will come to this ideal value.
Despite being one of this year’s three most active annual showers, the Quadrantids are often overlooked and under-observed. This is probably the result of their peak falling during the depths of the northern hemisphere winter, when the weather is often less than ideal for meteor observations.
For most of the fortnight they are active, Quadrantid rates are very low (less than five per hour). The peak itself is very short and sharp, far more so than for the year’s other major showers. As a result, rates exceed a quarter of the maximum ZHR for a period of just eight hours, centred on the peak time.
The Quadrantid radiant lies in the northern constellation Boötes, the Herdsman, and is circumpolar (never sets) for observers poleward of 40 degrees north. As a result, observers in northern Europe and Canada can see Quadrantids at any time of night. The radiant is highest in the sky (and the rates are best) in the hours after midnight.
For this reason, this year’s peak (at 2:20am UT) is best suited for observers in northern Europe – and given that peak rates can exceed 100 per hour, it is certainly worth setting the alarm for, to get up in the cold early hours, and watch the spectacle unfold.
Alpha Centaurids [S]
Active: January 31 – February 20
Maximum: February 8, 1:00pm UT = February 8, 9pm (WA) = February 8, 11pm (QLD) = February 9, 12am (NSW/ACT/Vic/Tas)
ZHR: Variable; typically 6, but can exceed 25
The Alpha Centaurids are a minor meteor shower, producing typical rates of just a few meteors per hour. But they are famed as a source of spectacular fireballs for southern hemisphere observers and so are worth keeping an eye out for in southern summer skies.
Alpha Centaurids are fast meteors, and are often bright. As with most showers that are only visible from the southern hemisphere, they remain poorly studied. Though typically yielding low rates, several outbursts have occurred where rates reached or exceeded 25 per hour.
The shower’s radiant lies close to the bright star Alpha Centauri – the closest naked-eye star to the Solar System and the third brightest star in the night sky.
Alpha Centauri is just 30 degrees from the south celestial pole. As a result, the radiant essentially never sets for observers across Australia. The best rates will be seen from late evening onward, as the radiant rises higher into the southern sky.
This year, the peak of the Alpha Centaurids coincides with the New Moon, making it an ideal time to check out this minor but fascinating shower.
Eta Aquariids [S preferred]
Active: April 19 – May 28
Maximum: May 6, 2pm UT = May 6, 10pm (WA) = May 7, 12am (QLD/NSW/ACT/Vic/Tas)
The Eta Aquariids are possibly the year’s most overlooked treat, particularly for observers in the southern hemisphere. The first of two annual showers produced by comet 1P/Halley, the Eta Aquariids produce excellent rates for a whole week around their peak.
The radiant rises in the early hours of the morning, after the forecast maximum time, and best rates are seen just as the sky starts to brighten with the light of dawn. It can be well worth rising early to observe them, as rates can climb as high as 40 to 50 meteors per hour before the brightening sky truncates the display.
Eta Aquariid meteors are fast and often bright, and the shower regularly rewards those who are willing to rise early. Spectacular Earth-grazing meteors that tear from one side of the sky to the other can be seen shortly after the radiant rises above the horizon.
This year conditions are ideal to observe the shower, with New Moon falling on May 4, just two days before the forecast maximum. As a result, the whole week around the peak will be suitable for morning observing sessions, giving observers plenty of opportunity to see the fall of tiny fragments of the most famous of comets.
Southern Delta Aquariids, Piscis Austrinids and Alpha Capricornids [N/S; S favoured]
In most years, the approach of August is heralded by keen meteor observers as the build up to the Perseids – the second of the year’s big three showers. This year, moonlight will interfere, spoiling them for most observers.
But this cloud comes with a silver lining. A fortnight or so before the peak of the Perseids, three relatively minor showers come together to provide an excellent mid-winter show for southern hemisphere observers. This year, the Moon is perfectly placed to allow their observation.
These three showers – the Southern Delta Aquariids, Alpha Capricornids and Pisces Austrinids – favour observers in the southern hemisphere, though they can also be observed from northern latitudes.
Regardless of your location, the best rates for these showers are seen in the hours after midnight. Reasonable rates begin to be visible for southern hemisphere observers as early as 10pm local time.
The Southern Delta Aquariids are the most active of the three, producing up to 25 fast, bright meteors per hour at their peak, which spans the five days centred on July 30.
The Alpha Capricornids, by contrast, produce lower rates typically contributing just five meteors per hour. But where the Southern Delta Aquariids are fast, the Alpha Capricornids are very slow meteors and are often spectacular.
Like the Alpha Centaurids, in February, they have a reputation for producing large numbers of spectacular fireballs. This tendency to produce meteors that are both very bright and also slow moving makes them an excellent target for astrophotographers, as well as naked-eye observers.
Active: September 10 – December 10
Maxima: October 10 (Southern Taurids); November 13 (Northern Taurids)
The Taurids are probably the most fascinating of all the annual meteor showers. Though they only deliver relatively low rates (approximately five per hour from each of the two streams, north and south), they do so over an incredibly long period – three full months of activity.
In other words, the Earth spends a quarter of a year passing through the Taurid stream. In fact, we cross the stream again in June, when the meteors from the shower are lost due to it being exclusively visible in daylight.
So a third of our planet’s orbit is spent ploughing through a broad stream of debris, known as the Taurid stream. In total, the Taurid stream deposits more mass of meteoric material to our planet’s atmosphere than all of the other annual meteor showers combined.
So vast is the Taurid stream that there is speculation that it originated with the cataclysmic disintegration of a super-sized comet, thousands or tens of thousands of years in the past, and that the current shower is a relic of that ancient event.
Taurid meteors are slow, and are often spectacularly bright. Like the Alpha Capricornids, they have a reputation for producing regular fireballs, making them another good target for the budding astrophotographer.
Rather than having a single, sharp peak, Taurid activity stays at, or close to, peak rates for the best part of a month, between the maxima of the northern and southern streams, meaning that it is always possible to find some time when moonlight does not interfere to observe the shower.
Active: December 4 – December 17
Maximum: December 14, 6:40pm UT = December 15, 4:40am (QLD) = December 15, 5:40am (NSW/ACT/Vic/Tas)
Another of the big three annual meteor showers, the Geminids are probably the best, with peak rates in recent years exceeding 140 meteors per hour.
The Geminids are visible from both hemispheres – although the radiant rises markedly earlier for northern observers. Even in the south of Australia, the radiant rises well before midnight, giving all observers the rest of the night to enjoy the spectacle.
Moonlight will seriously interfere with the peak of the shower this year, washing out the fainter meteors, with the result that observed rates will be lower than the ZHR might otherwise suggest.
But the shower regularly produces abundant bright meteors, and yields such high rates that it is still well worth checking out, even through the glare of the full Moon.
The final shower of the year – the Ursids – is a treat for northern hemisphere observers alone. Much like the shower that started our journey through the year, the Quadrantids, the Ursids remain poorly observed, often lost to the bleak midwinter weather that plagues many northern latitudes.
But if skies are clear the Ursids are visible throughout the night, as their radiant lies just 12 degrees from the north celestial pole. As such, they make a tempting target for observers to check out in the evening, even if the radiant is at its highest in the early hours of the morning.
Most years, the Ursids are a relatively minor shower, with peak rates rarely exceeding ten meteors per hour. They have thrown up a few surprises over the past century, with occasional outbursts of moderately-fast meteors yielding rates up to, and in excess of, a hundred meteors per hour.
While no such outburst is predicted for 2019, the Ursids have proven to be a shower with a surprise or two left to show and so may just prove to be an exciting way to end the meteoric year.
If you have a good photo of any of this year’s meteor showers that you’d like to share with The Conversation’s readers then please send it to firstname.lastname@example.org. Please include your full name and the location the photo (or any composite) was taken.