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Issue 16 Winter 2016

theWeather Club Newsletter

Winter 2016:

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Newsletter Dive into theWeather Club

theWeather Club 104 Oxford Road Reading RG1 7LL Tel: 0118 956 8500

Weather Report

Weather news stories from around the world during the last three months

Research News

An update on recent scientific research

Weather Applications

Winter sport inspiration

Weather Watch

Spotting the Aurora via social media

World Weather

A traveller’s guide to Banff, Canada

Science Lesson

What do we mean by climate change?

Weather and Climate view

Paul Hardaker and Ellie Highwood go festive talking Christmas and clouds

My Weather

Freya Squires shares her job flying on the UK's largest research aircraft

Weather Facts

And finally...

[email protected] www.theWeatherClub.org.uk www.facebook.com/RMetSoc @RMetS

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theWeather Club Newsletter

Issue 16 Winter 2016

+ Weather

Welcome Dear Weather Club readers,

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Autumn 2016 has been spectacular. It seemed this year the season really reached its full potential, with the landscape changing from shades of green to a spectrum of red, gold, orange and brown. As we approached the end of autumn, the mostly settled weather turned much more changeable. Storm Angus became the first named UK storm of the winter 2016/2017 season (page 3).

UK Weather September 2016

1981 - 2010

Actual

Anomaly

Average Max

18.3°C

+1.8°C

Average Min

11.0°C

+2.2°C

Mean Temp

14.6°C

+2.0°C

Sunshine

118.5 hrs

95%

Rainfall

98.9 mm

103%

Chloe Moore Author and Editor of theWeather Club Newsletter

In this edition, we have several exciting guest feature articles on topics including ice swimming (page 6), spotting the aurora from the ground and the north pole (pages 7 & 12) and the formation of "mother of pearl" clouds (page 13). Freya Squires, a chemist who works on the UK's

largest research aircraft reveals the work on-board this flying laboratory on pages 14 & 15 in our 'My weather' feature. As meteorologists, it's the time of year when we're always being asked 'Will it be a white Christmas?' See the answer on page 16 and read the full article on our website. Finally, I wish all of our readers a wonderful winter break, a very Merry Christmas and a healthy and happy New Year. @RMetS RMetSoc Search: RMetS

rmets_

New cloud type spotted over Snowdonia These dramatic clouds are the newest cloud type in over 50 years and were spotted over Snowdonia, Wales in early-November. Asperitas formations are incredibly rare and look like rough, sea waves in the sky. The base of these clouds is usually between 4,000 - 10,000ft (1 – 3km) and as with all cloud names, are derived from Latin with aspero meaning ‘roughness’. At first glance, they may appear to fall into the undulatus clouds category, however they are more chaotic and have less horizontal structure compared to undulatus clouds.

change in wind direction with height causes the wavy patterns. Although asperitas are not new to the sky, officially recognising them as their own cloud type is just in the process of being accepted. Back in 2006, The Cloud Appreciation Society suggested that asperitas clouds were labelled as their own cloud type after receiving photographs from around the world that they felt just didn’t fit within the existing cloud types.

After several years, the World Meteorological Organization (WMO) have now accepted this proposal, and asperitas will be added to the 2017 International Cloud Atlas; the first new cloud type since 1951, when cirrus intortus was accepted. The clouds below were observed at around 1600 on Sunday 13 November 2016 over the Ogwen Valley in Snowdonia National Park, Wales, with the photo captured by Patrick Hickie, a mountaineer instructor.

Although unstable atmospheric conditions are required, it is unknown exactly how the wavelike pattern that define asperitas form. One explanation is that the sightings are associated after convective thunderstorms. Another theory suggests that they were firstly mammatus clouds that begin to descend and then a Rare asperitas clouds were captured over Wales by mountaineer Patrick Hickie

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theWeather Club Newsletter

Issue 16 Winter 2016

Autumn 2016: Hot & humid to icy cold Weather Report September - November 2016

September was changeable with spells of hot and humid weather, leading to the joint-second warmest September in more than 100 years, with mean temperatures 2.0°C above the 1981-2010 long term average. High pressure over northern Europe during the second week drew warm air northwards and led to NHS England issuing a level-two heat alert. On 13th the UK recorded its hottest September temperature since 1911, reaching 34.4°C at Gravesend, Kent. Disruptive thunderstorms followed the hot weather in the coming days. Manchester City's game in the Champions League was postponed, as well as Manchester Town Hall flooding for the first time in decades. Further very intense bursts of rain on 15th saw almost two inches of rainfall (49.2mm) in Amersham, Buckinghamshire. The rest of September remained changeable with no major weather impacts. There were a few heavy thunderstorms on the 1st October, with high pressure and the easterly flow of air keeping temperatures close to average for the first two weeks. From 15th – 19th there was a spell of wet and showery weather, before returning to more settled conditions over England, Wales and Northern Ireland. The benign weather created mist and fog patches on several mornings at the end of October, but after clearing gave way to sunny and mild afternoons. Elsewhere over Scotland, wet and windy weather from the 25th - 30th saw wind speeds reach 64mph at Sella Ness (Shetland). It was another warm Halloween with the month’s maximum temperature recorded at 22.2°C at Trawscoed (Dyfed) on

Warm, dry and sunny conditions with a lack of windy days and frosty nights resulted in a spectacular autumn (Source: Deposit Photos)

31st October. Overall, UK rainfall was just 38% of average for the month; the sixth driest October in a series since 1910. The start of November saw more benign weather followed by a cold spell on 5th - 9th with snow across Northern England on 8th and 9th causing Leeds Bradford Airport to temporarily close. On 19th November, Storm Angus became the first named storm of the 2016/2017 season hitting southern areas of the UK. Wind speeds reached 81mph at Langdon Bay, Kent with 59mm of rainfall in Exeter, Devon. The end of November bought several crisp, dry and cold days. Rural spots, such as Sennybridge, Powys dipped to –9.7°C on the morning of 30th, giving the coldest November night since 2010. Even towns and cities reported low temperatures of -5°C, resulting in minimum November temperatures for the UK 1.6°C below the monthly norm.

Mini-tornado reports crushed following site investigations On Thursday 17th November, reports suggested a caravan site near Aberyswtwyh had been damaged by a tornado with other areas in Wales and the West Midlands suggesting ‘mini-tornadoes’ hit the area.

UK Weather October 2016

1981 - 2010

Actual

Anomaly

Average Max

13.3°C

+0.6°C

Average Min

6.3°C

+0.1°C

Mean Temp

9.8°C

+0.3°C

Sunshine

107.7 hrs

117%

Rainfall

48.9 mm

38%

The day's weather conditions bought a narrow band of squally showers, hail and damaging gusts, as a cold front tracked eastwards. Wind speeds Damage at a carvan-site 1 mile from Aberystwyth gusted up to 94mph at Aberystwyth (Credit: @thomasscarrott, Twitter) lifeboat station in Wales and reached directions with litter following a constant 84mph in Shawbury, Shropshire path. Site investigations following the Photos across social media illustrated event found that in this case, all the the damage, showing roofs ripped trees fell in roughly the same direction off houses, caravans overturned and and the damage occurred in isolated even a trampoline on the roof of a clusters, leaving the ground between bungalow in Milford Haven in Wales. affected areas mostly clear. The overall conclusion was that there was no strong Typically, damage patterns from a evidence for tornadoes and damaging tornado involve debris scattered in all winds were the most likely culprit.

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Weather Report

Issue 16 Winter 2016

Central America hit by latest hurricane on record Hurricane Otto made landfall as a category 2 hurricane in southern Nicaragua on the last Thursday in November (coinciding with Thanksgiving in America) bringing sustained wind speeds in excess of 100mph. The storm was fuelled by energy from the Atlantic Ocean with sea surface temperatures in and around the region unusually warm at 29°C (84°F). On 24th November, Otto quickly intensified reaching category 2 status and became the 17th hurricane of the 2016 Atlantic hurricane season.

UK Weather

With Otto forming much later than normal and Hurricane Alex forming

November 2016

1981 - 2010

Actual

Anomaly

Average Max

8.1°C

-1.0°C

Average Min

1.7°C

-1.6°C

Mean Temp

4.9°C

-1.3°C

Sunshine

74.6 hrs

130%

Rainfall

107.9 mm

89% Damage in Costa Rica following Hurricane Otto (Credit: Guillermo A. Durán, Flickr)

back in January, 2016 was the longest Atlantic hurricane season on record, lasting over 10 months. The National Hurricane Centre (NHC) states that when Otto made landfall in southern Nicaragua it packed winds of at least 110mph. Videos illustrating the damage show widespread flooding, and bridges and roads destroyed. Otto then continued to track westwards along the Nicaragua-Costa Rica border and is the only tropical storm or hurricane whose centre moved directly over Costa Rica since records began back in 1851. Panama was also affected with 22 fatalities across the three countries in total and US$9 million worth of damage to roads and highways alone. Around 8 hours after first making landfall on the east coast, Otto emerged in the Pacific Ocean, by which time it was downgraded to a tropical storm. Normally, hurricanes in the Pacific Ocean are re-named using a different system, however, because it retained its tropical characteristics, the name Otto stuck.

Arctic sea ice shrinks to second lowest on record

An ice-free Arctic during the summer months is just a few decades away based on current climate predictions

Looking at data from the last four decades, Arctic sea ice used to cover an area over 7 million km2 in the 1970’s. However, the area has lost more than half of this sea ice over the years. During September, the time of year when sea ice is at its smallest extent at the end of the summer

season, sea ice cover dipped to 4.14 million km2 this year. That’s just behind the record smallest extent back in 2012 at 3.39 million km2 and is jointly tied with 2007 as the second lowest minimum in the satellite record. Climate model simulations predict that the remaining half of the ice could disappear by 2030, leaving the Arctic ice-free in the summer. Only if greenhouse gas emissions are reduced rapidly could we prevent the seaice disappearing each year, with the current 2°C target insufficient to prevent the Arctic sea ice shrinking. New research published just this month in the journal Science (DOI: 10.1126/science.aag2345) has concluded that for every tonne of CO2 emitted, 3m2 of summer sea ice cover disappears, an area slightly smaller than a ping pong table. What exactly is one tonne of CO2? That’s a return flight from New York to London, or the average emissions of a UK citizen every seven weeks.

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Issue 16 Winter 2016

New weather satellite successfully launched into orbit The latest weather satellite has been successfully launched into orbit by NASA on 19th November. It features six new sensors, much greater processing power and will capture more hi-res imagery, improving weather observation capabilities, leading to more accurate forecasts and warnings. The Geostationary Operational Environmental Satellite-R (GOES-R) lifted off from Cape Canaveral Air Force Station in Florida and is being managed by the National Oceanic and Atmospheric Administration (NOAA). It took two weeks for the GOES-R satellite to reach its final destination, where it sits at a fixed point 22,300 miles above the earth’s surface. It will undergo testing over the next few months, with plans to become operational within the next year. Weather satellite data is so advantageous because it provides a complete and continuous picture of atmospheric conditions, such as clouds, water vapour and surface features, whereas ground-based instruments can only measure the surface conditions.

Research News

weather, such as where tornadoes are forming and how thunderstorms are intensifying, with potential to increase lead time for severe storms warnings. The image systems on the new satellite will also equip scientists to better understand the composition of the atmosphere through studying ash, dust and smoke plumes, providing a leap forward for climate scientists who are interested in studying the production of chemicals from lightning strikes, volcanoes and other atmospheric processes. The launch of this new satellite will give meteorologists and climate scientists the technology needed to help improve weather forecasting and measure how weather and climate are varying over time.

One of the most exciting new features on the new satellite is a sophisticated lightning mapping device. Normally, lightning data comes from a surface-based network, which can only detect cloud-to-ground lightning. However the new instrument on board this satellite can map all types of lightning continuously over the Americas and adjacent oceans. Research has shown that lightning flash rate increases can be a predictor of impending severe

An artist's impression of the GOES-R satellite as it travels through space (Source: NASA)

Saturn's jet stream whizzes round at over 1,000mph Using the hubble telescope, researchers were able to study storms on the second largest planet in our solar system The weather on Earth can be extreme and unpredictable, so just imagine how powerful the weather can be on a planet 750 times the volume of earth. New research has revealed that Saturn has the widest, most intense jet stream out of all the planets in our solar system with wind speeds zooming at over 1,000mph. Last year, the Planetary Sciences Group at the University of the Basque Country, Spain, were studying Saturn’s atmosphere when they discovered a white spot on the planet’s equator. It was a remarkable find as the spot was moving at speeds that had not been observed since the 1980’s. The white spot was in fact a storm 4,000 miles wide and by studying this and the movement of the clouds, they could determine new information about the structure of Saturn’s equatorial jet-stream. The researchers established that in Saturn’s upper atmosphere wind speeds reach

almost 700mph, and at altitudes exceeding 100 miles the winds travel at an impressive 1,025mph. By studying the weather of other planets, the team’s research will go towards improving the understanding and modelling of atmospheric processes on our own planet. Their findings were published in November in the scientific journal Nature Communications (DOI: 10.1038/NCOMMS13262).

750 earths could fit inside the giant saturn (Source: NASA)

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Issue 16 Winter 2016

+ Weather Applications Come on in Jonathan Cowie, editor of outdoor swimming magazine H2Open, explains the joys of taking the plunge in the outdoors this winter In late November I received a text from my friend Mandy: “Do you want to go for a swim?” Nothing odd about that you might think. But outside, even though the sun was shining brightly, a thick frost covered the ground. And the swim she was suggesting was outdoors in an unheated lido – and we wouldn’t be wearing wetsuits.

minutes. This isn’t swimming for exercise. So why do we do it? For me, it is the adrenaline-rush of the thrill of the cold. It makes me feel alive. I can’t think of a better way to start the day. Cold water swimming is a mental and physical challenge - just getting into the water is small victory. It also gives

water is literally freezing. It isn’t just schoolchildren who look forward to snow and ice, for cold water swimmers it is the perfect way to help banish the winter blues. Six Tips for Cold Water Swimming 1. Acclimatise As the temperature drops in autumn, just keep swimming and your body will get used to the cold. 2. Be safe Open water can be dangerous. Only ever swim where it is safe, and make sure you can enter and exit the water quickly and easily. Never swim on your own. 3. Wear the right kit

Jonathan at a winter swimming gala in Windermere

Ice swimming in Moscow, Russia

As outdoor swimming has grown in popularity over the past few years, many swimmers have decided to take on the challenge of swimming through the seasons, whatever the weather. This morning at Tooting Bec Lido the water temperature was a finger-and-toe-numbing 4.8°C, yet the pool was busy with swimmers.

you a real connection with the natural world; you are in tune with the passing of the seasons. The weather, as well as affecting swimming conditions, also changes the mood of a swim; a cold water swim in bright sunshine is a very different experience to one in torrential rain, even if the water temperature is the same.

We all have our little rituals when it comes to winter swimming. I like to swim one length head-up breaststroke, huffing and puffing, before I put my face in the water and swim front crawl. That way I can delay the onset of the dreaded ice-cream headache.

As we warmed up afterwards in the busy sauna, talk turned to the coming months. Would it be a harsh winter? And, more importantly, would the pool freeze over? For the past few years it hasn’t been cold enough for ice to cover the pool, but when it does the lifeguards cut a channel in the ice and we keep swimming, even though the

When the water is this cold, you can’t swim for very long – often just a few

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Wear a swimming hat (or two!) to help preserve body heat. You can also wear neoprene gloves, booties, a balaclava or a wetsuit. 4. No diving Do not dive or jump in unless you are used to the cold water. Cold water can cause gasping of breath and cold water shock, which can be dangerous. 5. Know your limits As the temperature drops, decrease the amount of time you spend in the water. 6. Warm up slowly Don’t have a hot shower. Hot water can cool your core and it can be dangerous. Instead, make sure you have plenty of warm clothes, wrap up well and have a hot drink.

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Issue 16 Winter 2016

+ Weather Watch

Citizen science project tracks Northern Lights

Winter brings shorter days and longer nights, providing the dark skies that are needed for spotting the spectacular Aurora. Michael Cook from the Aurorasaurus project explains how to find if they'll be visible over you, wherever you are. Here on Earth we experience a wide variety of weather and are familiar with its effects on us. Terrestrial weather is something that we can see happening right in front of us, unlike space weather. The United States National Oceanic and Atmospheric Administration (NOAA) recognizes space weather as a type of weather and define it as "the variations in the space environment between the sun and Earth". Space weather can occur anywhere from the surface of the sun to the surface of Earth, with one of the many results from space weather the beautiful aurora borealis (Northern Lights) and aurora australis (Southern Lights). But what causes this spectacular light show? Northern Lights are the result of electrons colliding with the upper reaches of Earth’s atmosphere. The electrons are energised through an acceleration processes and those

Dunluce Castle in County Antrim, N.Ireland, taken in October 2013 (Credit: Alistair Hamill; @ahamillphotos)

energised electrons then follow the magnetic field of Earth down to the polar regions where they collide with oxygen and nitrogen atoms and molecules in Earth’s upper atmosphere. Once the atoms and molecules calm down they release energy in the form of light. While the northern lights are a beautiful product of space weather, they are hard to predict and not the easiest to see. As the space weather community continues improving their ability to forecast the aurora, a citizen science project called Aurorasaurus was created in 2012. This project helps people throughout the world track the aurora by providing the first real time global map of auroral visibility. Those who download the free app or visit the Aurorasaurus website are able to submit real time reports of where they are currently seeing the northern lights.

The Aurorasaurus team then uses the citizen science observations to improve aurora now-casting and alerts of the visibility for the public. An interesting trend that this project has helped discover is that often user observations are seen further south than what a leading auroral forecast model predicted. Aurorasaurus is improving models and helping now-cast the aurora as well as the project studying different, lower latitude types of aurora that are rare and not fully understood. Aurorasaurus is a growing community with almost 5,000 registered users and over 3,000 followers on Twitter. Not only does this citizen science project help track the aurora, it helps raise awareness on many topics related to the aurora. Blog posts are released every few weeks, some even with quizzes so you can test your knowledge. Newsletters are sent out to our community and provide a quick summary of what’s new at Aurorasaurus and a little recap of the recent aurora activity. Space weather is an important part of meteorology and it is critical to understand and be able to forecast. If you’re fascinated by the aurora and want to learn more then join the Aurorasaurus community. The team is very interactive and always open to questions; they love helping the public track and understand the aurora!

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Issue 16 Winter 2016

+ World Weather A traveller’s guide to Banff, Canada Situated on the edge of the Great Continental Divide, dramatic scenery and changeable weather define Banff Rocky Mountains, turquoise lakes and more than 1,000 glaciers are just some of the sights you can expect to see when visiting Banff, Canada’s first National Park. Whether you visit whilst it’s a winter wonderland or travel in the summer when meadows explode into flower, Banff national park will show you some of the country’s most magnificent scenery.

it an excellent year to visit. Banff itself is located at an elevation of 1,383 metres (4,537 feet) and is the highest town in Canada, situated on the edge of the Great Continental Divide. With activities such as skiing, biking and hiking all popular in Banff, or even just driving through the area, are all dependant on the weather.

Lonely Planet, the world’s largest travel guide book company, ranked Canada the best travel destination for 2017, as well as next year also marking 150 years of Canadian independence. To celebrate, the country is offering free admission for everyone from around the world to all 47 national parks and 168 heritage sites, making

As with every region around the world, the weather in any one place is affected by latitude and the surrounding topography and oceans. Banff lies 350 miles inland from the Pacific Ocean, with the prevailing westerly winds often bringing in moist air from the Pacific. This air is then forced to lift which cools and precipitate out as the mountain peaks rise. Banff lies just

Banff National Park is located in the Canadian province Alberta (Source: Web Britannica)

to the east of the Continental Divide, providing one, final barrier for the air to climb, which further reduces the temperature of the air and removes a considerable amount of moisture. Banff town and the surrounding national park are open all year. Owing to the dryness of the air, daytime and night time temperatures can vary, sometimes by up to 20 or 25°C each day. From season to season, large annual temperature variations see average highs of 22°C in the summer and lows of -15°C during the winter months. July is the warmest month with average highs of 22°C in the town of Banff. Generally, the summer is reasonably short with the best weather during July and August. As Banff is so far north, summer daylight can last for more than 16-hours.

The view from Sulphur Mountain after taking the Banff gondola (Photo credit: Paul Gorbould, Flickr)

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May, followed by September and October are transition times of year

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Issue 16 Winter 2016 provides incredible views of the valley with the opportunity to climb an extra kilometre to reach the very top of the summit. Rafting, canoeing, biking, hiking, climbing and golf are just some of the other activities you can get involved with whilst in Banff. Or if it's too cold to get out of the car, just driving along the scenic highways provides numerous breath taking vista points, such as along Tunnel Mountain Drive.

Moose are just some of the wildlife that can be spotted in and around Banff (Photo credit: Russ Osborne, Flickr)

Plenty of snow at Sunshine ski resort, near Banff (Photo credit: Doug Zwick, Flickr)

when it’s possible to experience any type of weather from blizzards to bright, sunny, summer weather. Towards the end of May, the lakes begin to thaw as the warmer weather melts the ice, with June typically the wettest month with around 55 – 60mm of rainfall.

coldest month with average lows of -15°C, however cold snaps can see temperatures plummet to -30°C, with the coldest ever temperature recorded in the region at -51°C. Wind chill can make it feel even colder, sometimes by up to 10°C. Thankfully, the air is relatively dry which makes the extreme temperatures slightly more bearable!

Winter is Banff’s longest season between November and March, with prime skiing from February to April, after plenty of snowfall. Hiking trails become unpassable, sometimes not clearing until June. Even on the highways snow tyres are required from November to March to ensure vehicles are equipped to safely deal with the wintry conditions. Avalanches are a major hazard in the area, particularly in the back country. Despite the heaps of snow appearing beautiful, it may have not properly settled and can be incredible dangerous. January is the

With over 4 million visitors annually, the park’s hotspots can be become busy and overcrowded, especially during the summer. But with an area over half the size of Switzerland to explore, getting off the beaten track, into the forest and away from the crowds is easy and will allow you to escape it all. In just eight minutes, the Banff Gondola takes you all the way to the top of Sulphur Mountain providing panoramic views around the Canadian Rockies. At over 2,200 metres above sea level, the journey

Lake Agnes tea house is another gem. Starting out at Lake Louise, a 3.4km steep, winding hike will reward you with the Lake Agnes teahouse. Originally built in 1901 as a shelter for hikers, today it now serves tea, and cakes to anyone who makes it to the top! The staff who work there walk the trail two to four times a week, bringing in fresh items like vegetables and cheese. Sometimes horses are used to bring in extra baking supplies, but most of the dry goods are flown in by helicopter once a year at the start of the season. Whether you embark on a fly-drive holiday staying in luxurious mountain lodges or hike around with your backpack and camp, jaw-dropping scenery, extreme outdoor activities and hot chocolate in one of the world's most picturesque teahouses are just a few of the highlights that a trip to the Canadian Rockies offers to all.

Climate of Banff Average minimum temperature: -14.9°C in January Average maximum temperature: 22.1°C in July Average rainfall: 281.3 mm a year Average snowfall: 243.7 cm a year Sunshine hours: 7.8 hours a day in December 16.5 hours a day in July

Looking down on Lake Louise from the Big Beehive Summit Ridge

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Issue 16 Winter 2016

+ Science Lesson What do we mean by climate change? Climate change is frequently in the news these days, but what does it mean? To address this question we need to understand what climate is. Briefly, climate is a short hand way of summarising the weather experienced over a particular period of time. Mostly we are familiar with climate averages such as average temperature or rainfall experienced at a location. But other weather factors are also part of climate such as wind, sunshine, and cloud.

Furthermore although averages are useful they don’t tell the whole story. We also need to summarise how much these elements might vary during the same period. This might include their range and information about how large and how often extremes occur. Internationally local climate standards are assessed over thirty year periods. Averages and ranges may also be assessed for larger areas and indeed for the world as a whole. The climate of the earth is largely determined by several astronomical factors: 1. the strength of the sun and distance from earth; 2. the speed of rotation of the earth ; 3. the tilt of the earth’s axis. Atmospheric constituents, such as gases, aerosols, dust and clouds and the configuration of the earth’s surface, so land, ocean or ice, also affect the climate. Locally the climate is affected by latitude, altitude, local and regional geography and time of year, so this must be considered as well. Recent climate can be computed from weather records. For periods going back further in time we use records of factors

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Issue 16 Winter 2016

This visualisation of temperatures in Lancashire (UK) shows annual mean data from 1754-2015. The long-term warming trend is clear. The 19th century average is represented by the black line. (Source: ClimateLabBook, Ed Hawkins) that are affected by the climate – such as tree rings, climate sensitive species and deposits of mud, snow and rock. What do we mean by climate change? In general terms climate change relates to changes in climate between different periods of time, long enough to minimise the effects of short term variations, both locally and globally. However current interest has focused on an observed warming of the global climate over the past 150 years. In fact 2015 was the warmest year on record at about 1°C above the 1850-1900 average (Ref 1). The scientific community and policymakers are interested in understanding the reason for this warming and what may happen in the future, as it has considerable implications for human society. There is a lot of indirect evidence that the global climate has changed in the past. Over the last few million

years the earth has been in a relatively cool phase during which large polar ice sheets have grown and then receded several times, in a quasi cyclical manner, related to changes in astronomical factors. Further back in time much warmer episodes have been related to higher levels of atmospheric carbon dioxide, about 3 million and 55 million years ago (Ref 2). Since the end of the last ice age, 10,000 years ago, the world’s climate has been fairly stable, but regionally there have been important natural fluctuations. So the question is whether the climate change we have observed over the past 150 years is part of a longer term climate cycle, natural variability or a long term change related to some external factor? The evidence we have is that it is largely the result of changes to the composition of the atmosphere –

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the growth in so called greenhouse gases, such as carbon dioxide, which trap heat in the atmosphere and lead to changes not just in the global and local climate. The scientific challenge in understanding climate change is to separate out the effect of greenhouse gases from other potential factors and being able to predict the future course of climate change if greenhouse gas levels continue to grow due to human activities. References Ref 1: WMO Statement on the Status of the Global Climate in 2015, WMO, 2016. Ref 2: IPCC 5th Assessment Report. Chapter 5. The Royal Meteorological Society would like to thank David Warrilow for writing this article.

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Issue 16 Winter 2016

+ Weather View

Prof Paul Hardaker Chief Executive of The Institute of Physics

Father Christmas has a 1-in-10 chance of seeing the aurora borealis In Norse mythology the Valkyries are servants of Odin choosing those that live and die in battle. The legends have it that when they gallop out in to the night their weapons and armour shimmer in the darkness, creating the aurora. It may not be as glamorous as shimmering reflections from immortal virgins, but I think the scientific explanation is equally impressive.

suggested they were caused by a release of concentration of electrical charge, but it was Kristian Birkeland, a Norwegian physicist, who developed a full theory of the effect in 1908. He was nominated seven times for the Nobel Prize for his work, but Birkeland's theory was dismissed by mainstream physics until after his death so he never received global recognition in his lifetime.

It’s always dangerous, in my experience, to identify the first person to be credited with some scientific discovery

The aurora is, of course, a high latitude phenomena that we can see at both poles, the aurora borealis (Boreas is the

instruments on Mars Express spotted the first Martina aurora. Having said all of that I have to confess I still have not witnessed them myself, much to my regret; I’ve tried twice and not a twinkle. Sadly I missed the very active year associated with the solar maximum in 2014, but I am told that the aurora is still prevalent two to three years either side of the maximum. Both March and October are known as the best time of year to spot the aurora, as this corresponds with the equinoxes, providing an optimum combination of darkness, low cloud and solar activity. If you do go in search then be sure to check out an aurora forecast. Despite a strong claim by the North Pole, according to the Finnish, Father Christmas lives in Rovaniemi, Lapland. I read that in Rovaniemi at this time of year there is a one-in-ten chance of seeing the aurora on any one night, which I am certain must be based on robust scientific observation and not cynical marketing. So luckily for Father Christmas he probably gets quite a good view just from his house.

or explanation, as usually they turn out not to be. Perhaps that’s just the addictive nature of science; standing on the shoulders of giants as Newton said (or was that Bernard of Chartres in 1159). The French mathematician and astronomer Pierre Gassendi is generally credited with using the name aurora in 1621, after the Roman Goddess of dawn. However we know that others had seen this dating much further back in history. Writings from China, stretching back as far as 2600 BCE, describe detailed sightings of the aurora. Benjamin Franklin studies the northern aurora during his trips to Europe, back and forward across the Atlantic, and

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Greek god of the north wind), more commonly known as the northern lights, and the aurora australis, the less wellknown southern lights (read more about the science behind the northern lights on page 7). Thanks to observations like those from the Hubble telescope we now know that other planets have auroras too. The gas giants of Jupiter and Saturn have much stronger magnetic fields and their interaction with the solar wind can create spectacular aurora. Venus on the other hand has no magnetic field so there the aurora is produced by the impact of electrons precipitating in the night-side atmosphere. And on 14 August 2004

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For the time being I will have to settle for enjoying it through the many hundreds of photos and videos, or the artists and writers who have written about or represented the aurora in their works. With that in mind it seems fitting to finish with Benjamin Franklin Taylor, the American poet and war correspondent, as the namesake of the Benjamin Franklin, who wrote: To claim the Arctic came the sun With banners of the burning zone. Unrolled upon their airy spars, They froze beneath the light of stars; And there they float, those streamers old, Those Northern Lights, forever cold!

theWeather Club Newsletter

Issue 16 Winter 2016

+ Climate View

Prof Ellie Highwood President of the Royal Meteorological Society

Beautiful clouds but no silver lining Clouds are part of our everyday life, but are especially relevant during winter when night-time cloud duvets can be the difference between whether we have to scrape the ice from cars in the morning and grit the pavements.

cirrus clouds. But their altitude is not the only difference. Some of these clouds aren’t even made of water. Depending on the size of the particles that form them and their temperature, we classify PSCs as either Type 1 or Type 2.

But winter also brings a very special kind of cloud, one that is increasingly being seen, especially in Scotland and Northern England. These are Polar Stratospheric Clouds (or PSCs), and are unlike any other cloud we know.

Type 1 PSCs are made of ice crystals forming when temperatures are below the ice frost point, specifically -83°C. We also call these “mother of pearl” or nacreous clouds. Type 2 PSCs are formed at slightly higher temperatures and consist of droplets of nitric and sulphuric acid plus water. These Type 2 clouds are much harder to see because they are optically thin and do not scatter as much radiation from the sun.

Polar Stratospheric Clouds usually occur in the stratosphere, polewards of around 60°N and at an altitude between 10 and 25km – well above where we find even

Also known as nacreous or "mother of pearl" clouds, another siting from Scotland in February 2016 (Photo credit: Kit Curruthers, Flickr)

“... It is hard to believe that such beauty can play a key role in the destruction of ozone... which is not so beautiful.”

For a long time, PSCs have been a feature of the Antarctic stratosphere, where the lack of land sets up a very strong circumpolar atmospheric jet stream isolating the polar stratosphere from the lower latitudes. Air trapped here becomes very cold during the winter allowing PSCs to form. The PSC cloud particles provide a surface for chemistry to happen that converts “inactive” chlorine into forms that can damage ozone when the sun comes up in the spring. Thus PSCs are important agents in the formation of the ozone hole.

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Polar stratospheric clouds spotted in February 2016 over Alloa, Scotland (Photo credit: Alan Tough)

Recently though, PSCs have been becoming more frequent in the Arctic. The winter-time Arctic stratosphere is usually warmer than the winter-time Antarctic stratosphere because the circumpolar atmospheric jet stream around the edge of the so-called “polar vortex” is more often disrupted by weather systems. This allows the mixing of warmer air from lower latitudes into the polar-regions with higher temperatures causing PSCs to be less common in the Arctic. However, one feature of climate change is that whilst the global surface temperature gets warmer, the stratosphere cools due to the more effective radiation of infrared radiation to space by the extra carbon dioxide. A cooler stratosphere in recent decades has led to an increased frequency of Arctic PSCs. Although PSCs usually form north of the UK, it is sometimes possible to see them from our latitudes, particularly if the polar vortex has “wobbled off” the pole, as it can do when the flow is disrupted. They are beautiful clouds, so it is well worth keeping a look out for them, however it is hard to believe that such beauty can play a key role in the destruction of ozone, which is not so beautiful.

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theWeather Club Newsletter

Issue 16 Winter 2016

+ My Weather Freya Squires, research aircraft chemist Freya Squires is a first-year PhD student at the University of York who spent a year working at the Facility for Airborne Atmospheric Measurements. Her current research focuses on measuring emissions, some of which she does on board the atmospheric research aircraft. From 25th – 29th October 2016, Manchester Airport’s Runway Visitor Centre was taken over by a publicity event hosted by the Natural Environment Research Council, called “Into the Blue”. As well as forty exhibits showcasing ground-breaking environmental science happening in the UK today, Manchester became home for the week to the UK’s only large Atmospheric Research Aircraft (ARA). Anyone lucky enough to attend probably left knowing at least something about the ARA, managed by the Facility for Airborne Atmospheric Measurements (FAAM).

The ARA, a specially modified BAe 146-301, is a unique aircraft platform for atmospheric measurements and can fly as low as 50 feet above the sea all the way up to 35,000 feet. There is a lot of sophisticated equipment installed on the aircraft making it an impressive research resource capable of studying a wide range of atmospheric parameters. Instruments both inside the cabin and mounted underneath the wings are used to study a wide range of particles, including raindrops and snow. Concentrations of gases including greenhouse gases and those which

The ARA on the runway. (Photo credit: Ioana Colfescu)

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Freya Squires affect air quality, such as nitrogen oxides (referred to as NOx) can also be measured in real time as the aircraft flies through the skies. This huge flying laboratory has been deployed all over the world to investigate the atmosphere and it is safe to say that those lucky enough to work on the aircraft are very well travelled! In the last few months alone the aircraft has been chasing the monsoon as it moves across India and flying low over volcanoes in Iceland. However, the aircraft does not just spend its time in the far-flung corners of the globe. Much of the research takes place right here in the UK, including studies on the development of Atlantic

theWeather Club Newsletter

Issue 16 Winter 2016

storms moving towards Britain and the monitoring of emissions from North Sea oil rigs. As well as aiding high-impact scientific research, the aircraft has been called upon to respond rapidly to natural disasters. Following the 2010 eruption of the Icelandic volcano, Eyjafjallajökull, (when airspace was closed to regular aircraft) the ARA was still flying, monitoring the distribution of the ash cloud across the UK and Europe. More recently, chemists at the University of York have been exploiting ARA’s impressive air quality monitoring capabilities to investigate the accuracy of national emissions inventories. Recent studies found that for some regions there are discrepancies between measured emissions and estimated emissions published in inventories. Flight B991 took off from East Midlands Airport on the 24th October 2016, landing later that day at Manchester Airport. The aim of this flight was to measure the mass emission from the Manchester and Liverpool area. Preparation for a specific flight starts weeks in advance and flight B991 was no exception. In the days running up to take off on 24th October the ‘mission scientist’ takes time to carefully plan suitable routes to ensure the scientific aims of the flight are achieved. Routes also must comply with air traffic restrictions so there really is a lot to be considered. Weather forecasting is critical, particularly in the days before the flight. During flying periods, FAAM receive daily forecasts which provide information required for fight planning. Sudden changes in weather may mean that re-routing must occur or in some cases the flight is postponed altogether. Thankfully the flight to Manchester could go ahead as planned! On the day of the flight, work on the aircraft starts three hours before the planned take off time. The science crew warm up their instruments, carry out any required calibrations

Inside the ARA. (Photo credit: Ioana Colfescu) and complete a series of checks to ensure the best possible data set is obtained. The variable nature of the atmosphere and weather means that sometimes there is only one or two chances to get the measurement you need! During this pre-flight period the team of engineers and pilots carry out their essential checks to make sure it is safe to go flying. Flight B991 involved several straight level runs upwind and downwind of the Manchester/Liverpool area between 100 – 1500 feet (30m –460m). This

enabled the aircraft to sample the entire bottom layer of the atmosphere which allows scientists to calculate the total pollution emitted from this region. Flights like B991 demonstrate what a valuable resource FAAM’s ARA is in studying and understanding the atmosphere and weather. If you see a large blue and white jet flying low overhead give us a wave! For those interested in finding out more about the work that FAAM does visit www. faam.ac.uk or check out @faam146 on Twitter.

Flying low above an offshore wind farm on Flight B991. (Photo credit: Marina Schimpf (FAAM))

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+ Weather Facts Snowiest ski resort is Mount Baker in Washington state, USA, with an average of 16.5m of snow each year

Unique snowflakes Every snowflake that forms is different due to very slight changes in the environment as it falls

White Christmas Snow has fallen on Christmas Day somewhere in the UK 38 times in the last 52 years

Cairngorm, Scotland is the snowiest place in the UK recording 76 days of snowfall throughout the year (1981-2010 averages)

Buy the RMetS 2017 Calendar Featuring the winning and short-listed images from the Weather Photographer of the Year 2016 competition Available now Visit www.rmets.org/shop

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