Categories
Climate Climate Change Weather

Weather, Climate and Climate Change

This is probably one of our favourite short explainer type videos that we use when delivering teacher CPD and when talking to students. It uses the analogy of a dog and its owner to represent the relationship between weather and climate, and can be really helpful!   You can find classroom resources and further support materials for teachers in our Weather and Climate: a Teachers’ Guide chapter on weather and climate.
Categories
Climate CPD Teaching Weather

Resource Wins GA Silver Award

Rob Gamesby collects GA silver award

We were delighted that our Weather and Climate Teachers’ Guide/ scheme of work for 11-14 geography was awarded a ‘silver’ by the Geographical Association at their conference in April.

“This excellent – and free – resource, accompanied by differentiated PowerPoints, is well-structured, informative, and fits some complex weather and climate topics into a digestible format. The judges felt it is an accessible resource that provides support for subject specialist and non-specialist teachers alike. They liked the examples that the authors used and the way it makes connections from one lesson to another, building the learning along the way.”

Photo credit: Geographical Association/Shaun Flannery 2022

Categories
Secondary Weather

Tropical Continental Air Mass and Saharan Dust

This morning, skies were orange/ beige across much of England as a Tropical continental (Tc) air mass brought Saharan dust. 

Saharan Dust on Windscreen

Image credit: Geoff Jenkins

Read more about why the air was carrying so much dust, and see some stunning photos from Spain and France here. The further the air travelled, the more dust was deposited and the less dust remained in the air – so the most vivid skies were in the south. 

Read our guide to air masses for background information or show our YouTube explainer

weather chart 16th March 2022

How can you tell that there is Tc air from this weather chart (midnight on 16th March 2022)? 

The air approximately follows the isobars, shown as thin lines on this chart. To work out which way, you need to look at the pressure systems and remember that air goes clockwise around anticyclones (H) and anticlockwise around cyclones (L). 

Considering either the 962mbar Low or the 1033mbar High shows you that the air is coming from the south (a southerly wind) across England.

Following the isobar marked 1020 back, you can see that the air has come over Spain from Africa. This is a Tropical continental air mass.

Behind the occluded front, for much of Ireland, the wind coming from the west. The 1020mbar Low is a bit misleading, but you can see that the air coming up from the south diverts to curve round it in an anticlockwise flow. 

Tc weather chart
Categories
Extreme weather Geography Secondary Weather

Storm Eunice and Generic Case Study Template

Storm Eunice cloud and wind

We have created a new worksheet which allows students to collect information and create a case study of a named UK storm. As part of the worksheet, students collect and annotate weather chart and other information about the storm including weather warnings. 

Storm Eunice is given as a worked example. 

Categories
Books Primary Schools Weather

My First Book of Weather

My First Book of Weather

This beautifully illustrated children’s book is full of fantastic facts about weather, climate and the world around us. It would be a wonderful gift for primary school aged children, with plenty of engaging pictures to keep infants interested as well as lots of interesting facts and trivia to interest junior children. The author, Camilla de la Bedoyere, has written more than 200 books for children and adults, many of which explore the natural world. Cinyee Chiu, the illustrator, believes in a sustainable lifestyle and is interested in projects about environmental/climate issues.

Covering a wide range of subjects, the author and illustrator take us on a tour to discover: ‘what is weather?’ and ‘how does the weather change?’, including how forecasts and charts are made. The book also tells us about Earth’s past climate, wild weather, extremes and climate change. It covers an amazingly large range of topics and both children and adults will likely learn plenty of new information about weather and climate from reading this book together.

As you would expect, the book starts with a gentle introduction to the atmosphere, the Sun and the wind, but it soon goes beyond the more basic kids’ weather books as it shows examples of how wind is measured with the Beaufort Scale. The water cycle and formation of clouds is shown with accurate representations of the different types of cloud. In the section on how the weather changes, it starts with a selection of nature’s weather warnings, where I learnt a new and interesting fact about how crickets chirrup faster and louder as the temperature rises! This is nicely followed by an overview of how storms develop and how we forecast the weather. The only thing that is missing from this section is some time spent in the book talking about supercomputers and the importance of number crunching, which is somewhat glossed over. However, unlike other children’s books about weather, it is nice that this book includes information about weather charts and weather records. There is a large section on world weather, which spans from Earth’s past climate (both hot and cold) to climates and seasons, making links to migrations and the impacts of weather and climate on people. A weather book would not be complete without sections on wild weather, from hurricanes and tornadoes to extreme and strange weather, which is covered very well by this author and illustrator. Finally, climate change has a prominent place in this excellent book, with a focus on renewable energy and how it is generated.

The illustrations in this book are beautiful and the content very engaging and interesting, giving the perfect combination to keep children and adults interested from front to back cover. Dr Sylvia Knight (RMetS) was consulted during the writing of the book, so we can feel confident that the content is accurate. I would definitely recommend this book for primary age school children – a great gift and lovely to read with them as an adult too!

My First Book of Weather, Bedoyere, Camilla (Author) &  Chiu, Cinyee (Illustrator) Templar Publishing, 2021 Hardback £12.99, 64 pp ISBN 978-1-787418-50-9  
 
Reviewed by Jenny Rourke for Weather, July 2021
Categories
Geography Schools Secondary Teaching Weather

New Films: Air Masses and the ITCZ

We have made two new explainer films which can be seen on YouTube:

An Introduction to Air Masses

All About the InterTropical Convergence Zone (ITCZ)

 
global rainfall patterns
Categories
Blog Geography Secondary Teaching Weather

Air Masses

In this article we explore air masses – the idea that, by looking at where our wind is blowing from, and what has happened to the air in the wind on its way to use, we can begin to understand why we’re getting some particular weather.

We live on an island, and the weather can come at us from any direction, although in practice, it comes from some directions more than others  – this wind rose shows the direction the wind was recorded coming from at Heathrow airport, near London. The longer the bar, the more often the wind came from that direction, so you can see that our wind comes from between southwest and west most often.  

Lets take a step back and remember that warm air rises – whether that’s the air being heated in a hot air balloon or the air above a radiator (watch a simple demonstration).

What happens to the rising air? As it rises it cools. Cloud and rain are caused by warm air rising, warm air rising is called convection (watch a simple demonstration).

You can often see convection going on in the atmosphere – you get puffy cumulus clouds, with flattish bases and puffy tops where the cloud is bubbling up.

clouds

More generally, Clouds form when there is more condensation going on than evaporation in the atmosphere.

The colder it is, the less evaporation happens – so cloud forms when the air cools.

This isn’t just when warm air rises.

Now we can think about air masses, they are classified according to where they have come from, and what they have passed over:

UK air masses

One air mass generally covers the whole country.

However, it can bring different weather conditions to different places. For example, Tropical continental air can carry Saharan dust, but it mostly falls on the south of the UK – there isn’t much left in the air by the time it reaches Scotland.

Lets consider Polar maritime (Pm) air first (click on the map to start the animation):

Polar maritime air comes towards us from further North in the Atlantic. It starts cold, but is slowly warmed by the ocean below as it travels over progressively warmer water. It also picks up moisture from the ocean. 

As it is warmed, it becomes more unstable and inclined to rise, leading to convection and puffy Cumulus clouds, mainly over the ocean. As the air hits land (the western coast of Ireland, Wales, Scotland and England) the air, which was already inclined to rise, is forced up a bit more – forming more cloud, and giving rise to rainfall. 

Polar maritime air, our dominant air mass, brings cloud and rain to the west of the UK and relatively dry air to the east. 

This satellite image is typical of Pm air – you can see the puffy cumulus clouds over the ocean, and the belt of cloud over the western side of the country.  

Returning Polar maritime air (rPm) is air which is Polar in origin but which swings round to hit the UK from the west or even slightly south of west – but if you were to follow its path back, you would see that it was Polar. 

Arctic maritime (Am) air is extreme Polar maritime air, coming down to the UK straight from the north, over the Arctic ocean. It tends to bring wintry weather to Scotland and isolated snowy showers further south, triggered by air rising over the local orography. 

Polar Continental (Pc) air will also be cold to start with and get progressively warmer as it moves south, so you would also expect convection. However, the air will be very dry as it passes over continental Europe, so little cloud will form. The UK is a set of islands though and to reach us, the air must pass over the North Sea, picking up water vapour as it does so. The cloud and precipitation (typically snow in winter) it brings therefore primarily affect the east coast. The longer the path it takes over the North Sea, the more precipitation there will be. 

This satellite image is typical for Pc air – you can see the cloud free areas immediately to the west of the land masses, with cloud forming further east (ignore the front to the west of the UK and Ireland).

Of course, the characteristics of the air masses can be very different in the summer and the winter. Siberia, for example, is extremely cold in winter but relatively warm in summer – so a polar continental air mass can bring us bitterly cold weather and heavy snowfall (for eastern counties) in the winter, but much warmer weather in the summer.

The processes at work in Tropical Maritime (Tm) air are a bit different. This is warm air, which is being cooled from below as it moves north. You therefore wouldn’t expect any convection with air rising, cooling and forming cloud. However, the air is being cooled just by moving north and so eventually may reach the temperature at which cloud forms – flat, featureless sheets of stratus cloud because, on the whole, the air is staying at the same level.

As it is maritime air, there is plenty of water vapour available to form cloud droplets. The processes which give us big, fat raindrops are mainly associated with the vertical air motion and circulations in cumulus clouds. So Tm air at best gives a persistent drizzle.

The satellite image below shows the extensive sheet of stratus cloud over the Atlantic associated with Tm air.

We rarely experience Tropical Continental (Tc) air – air that flows up from the Sahara over continental Europe.  This is the warmest and driest air we can get – any moisture picked up over the Mediterranean will be rained out before it reaches us.

Tc air gives clear skies, as you can see in the satellite image below – again ignore the front to the west of the UK. In the summer, this can mean that some areas get particularly warm – maybe because of their colour (dark) or aspect (facing the Sun) – giving rise to late afternoon localised thunderstorms

A front is where two air masses meet. In the UK, the weather fronts associated with depressions usually separate polar and tropical maritime air.

If there is a front, then different parts of the UK can be experiencing different air masses. The weather on the fronts themselves is more extreme. 

Look out of the window now – what cloud types can you see? Does that tell you anything about where the air is coming from? You can have a look at earth.nullschool to see if you are right.

 

 

Categories
Careers Weather

Weather Forecasting Game

Try your hand at weather forecasting – can you beat the experts from University of Reading and beyond?

Calling all weather enthusiasts and wannabe forecasters! Following its successful launch to the public last summer, The Weather Game, run by the University of Reading is returning for another friendly competition round.

The game offers entrants the chance to try and predict the weather around the world and close to home. Points are awarded for correct weekly forecasts over six weeks, allowing people to take on their friends and try to beat the experts to top the league.

This activity gives school pupils and weather fanatics a glimpse at the science used on television forecasts or to monitor impacts of climate change. A number of high-profile TV weather forecasters like Laura Tobin and Tomasz Schafernaker made some of their first forecasts while they were students at Reading.

Forecasts from leading sources like the Met Office and BBC Weather can be used as a basis for predictions, but players are encouraged to follow their own intuition on where weather might differ from what is expected. For example, if changeable weather is certain or there is only a small chance of showers, going against the expert forecasts for sunshine and rain might earn you the points.

Entrants will make predictions on the temperature, precipitation and sunshine hours for three fixed locations: Reading, UK; Toronto, Canada; Hong Kong, China and also for another city that changes weekly. While travel is off the cards for most of us this year, experiencing the weather is something that connects us all.

Registration opens from Monday 7 June with entries due each Friday for six weeks at 19:00 London time.

Categories
Books Climate Climate Change CPD Geography Microclimates Schools Secondary Teaching Weather

Weather and Climate: a Teachers’ Guide

weather and climate teachers guideIn this teachers’ guide and the accompanying online teaching resources, we aim to give UK geography teachers all that they need to deliver relevant, engaging and thorough weather and climate lessons to 11–14+ year old students. They are not linked to any specific curriculum but should be easily adaptable to all.

The book is accompanied by high quality online background information/professional development resources for teachers.

 

 

 

The Royal Meteorological Society believes that:

  • all students should leave school with basic weather literacy that allows them to understand the weather that affects them, their leisure activities and the careers they choose to follow
  • every student should leave school with basic climate literacy that would enable them to engage with the messages put forward by the media or politicians and to make informed decisions about their own opportunities and responsibilities.

To this end, we have embedded a climate change thread throughout the online resources, showing its relevance to both weather and climate. An understanding of weather and climate is fundamental to an understanding of climate change.

There is a progression of knowledge through the topics, supported by review and assessment activities. The resources also progressively develop key geographical skills such as data, mapwork, GIS, fieldwork and critical thinking.

In this guide, we include common misconceptions which should be challenged in the classroom.

There are 20 topics or chapters. Across these, there are three threads or paths which can be taken through the online resources, depending on the teaching time available:

Basic weather: Weather in our lives, weather measurements, weather and climate, global atmospheric circulation, global climate zones, air masses, pressure and wind and water in the atmosphere

Climate: Weather and climate, global atmospheric circulation, global climate zones, past climate change, polar climate, hot deserts, changing global climate, UK climate, changing UK climate, the climate crisis

Extending weather: Anticyclones, depressions, microclimates, urban weather, tropical cyclones.

Many of the online teaching resources are available with standard or easier versions, as well as extension or alternative activities.

Find the scheme of work, teaching resources, background information for teachers, as well as the Teachers’ Guide (copies of which may be printed on request), here

All the online resources will be updated and revised regularly.

Categories
Blog Climate Climate Change Extreme weather Weather

Weather, Climate, Extreme Weather and Chaos Theory

How does climate relate to the weather?

We like to talk about the weather, to complain about its variability and to blame the weather forecasters for getting it wrong. But what is ‘climate’, and how does the weather we experience on a day-to-day basis relate to climate change, a subject which is increasingly dominating our newspapers and television screens? Why is it that we can’t make a perfect weather forecast? How can we hope to predict the climate of the 21st century, when we can’t say what the weather will be doing in a week’s time? If the climate changes, how does the weather change?

Firstly, how does the climate relate to the weather we experience on a day-to-day basis? We know from experience that the weather can be very different from one day to the next, let alone from one year to the next, without any change in the climate.

Surprisingly, dice are a good way to think about the difference between weather and climate…

The animation below allows you to choose how many times to roll a dice and then see how often you get each of the six sides. Try a low number of rolls, then try some larger number of rolls and see what happens:

 

Throw the dice a few hundred times. What is the average (mean) of the scores? The more throws, the closer the average gets to 3.5. If you were to throw the dice one more time, you would not be able to predict the number that the dice would land on, as the probability of throwing each number is the same. However, you could be very confident that the mean would still be 3.5.

But what has this got to do with weather and climate?

What if we associate weather types (for example, cloud cover) with each number on the dice?

Try rolling the dice in the animation, again explore what happens as the number of rolls increases.

As when there were numbers on the sides of the die, you can’t predict what the weather will be on the next throw. Climate is defined as being the average of the weather over a long (typically 30 years) period of time. The ‘climate’ of this die is 50% cloud cover. A single throw of 0% or 100% cloud cover won’t affect the climate very much if you are taking the average of 100s of throws. In the same way we can have a very hot summer one year, and a very wet one the next, without the climate, the weather we expect to happen, necessarily changing.

Climate is what we expect, weather is what we get

So why do the weather forecasters never get it totally right? Mostly because the weather is a ‘chaotic’ system.

Very small changes to the starting conditions can lead to completely different weather patterns developing. This observation led Ed Lorenz to suggest that the flap of a butterfly’s wings in the Amazon rainforest could lead to a tornado in Texas. It is very unlikely, but it could.

This means that, to make a perfect weather forecast, we need to know what the atmosphere is doing currently, down to the scale of individual butterflies flapping their wings, which is obviously impossible!

So, since tiny changes in the starting conditions of a weather system can make significant differences to the outcome, when making a forecast we have to try to take into account what might be happening now, as well as what might happen in the future to affect the atmosphere. The best we can do is to produce a range of forecasts, with some indication of what is most likely, or least likely, to happen.

To help illustrate this, consider throwing two dice instead of one:

 

With two dice, the probability of throwing a combined score of a number between 2 and 12 is not the same. There is only one combination of number that would give you a 2 or a 12 (two 1s or two 6s respectively) but, for example, for a combined score of 4 you could throw a 3 and a 1, two 2s or a 1 and a 3 – so you are 3 times as likely to throw 4 as 2 or 12. There are most possible ways of throwing a combined score of 7, and no way at all of throwing a 1 or 13 or more.

Move the slider to pick a number and throw the dice a large number of times. Notice the shape of the graph that is produced – the middle numbers are rolled more often than the smallest or largest numbers.

This sort of shape of ‘bell shaped’ graph is very common. For example, temperature measurements will often show a similar distribution, although temperature can of course take any value, not just the numbers one to twelve.

In this way, the results of many weather and climate forecasts can be combined to show what is most likely to happen, what is unlikely to happen and what almost definitely won’t happen.

But what about extreme events? How will the likelihood of an extreme event change as the climate warms? It is never possible to attribute one particular event to a particular cause. To go back to the dice example, you could load a die so that sixes occur twice as often as normal. But if you were to throw a six using this die, you could not blame it specifically on the fact that the dice had been loaded. Half of the sixes would have occurred anyway, even with a normal die. Loading the die just doubles the odds of throwing a 6.

In general, if the climate warms, the whole bell-shaped curve of temperature for a particular place shifts to warmer temperatures:

Graph 1

Taken from the Synthesis report on Climate Change, 2001, ipcc.ch

Record hot events are more likely in a warmer world, and record cold events are less likely.

So, for example, we can say that the hot summer of 2003, which killed 22,000 – 35,000 people in central Europe, is twice as likely because of the global warming that has resulted from the man-made emissions of greenhouse gases. By 2050, we can expect summers as hot as that every other year.

Similarly, in the U.K., we can expect the number of extremely rainy days, with associated flooding, to increase. Already, the kind of rainfall that you could have expected once every 30 years in the 19th century is happening once every 12 years now. By the end of the century, it could be expected every 4 years.

So, we can adapt the earlier phrase about weather and climate to 

Climate is what you affect, weather is what gets you

So, to summarise:

  • Even with perfect forecasting techniques, we could never say exactly what the climate will do over the next century. This is because:
    • weather is chaotic
    • we don’t know how the world will develop and how much greenhouse gas will be emitted
    • We don’t know what other, natural, factors may affect the climate in the future – volcanic eruptions, changes in solar activity etc.
  • We can, at best, say what the climate is most likely to do, and what it probably won’t do.
  • The longer into the future a forecast is made, the less certain you can be about what will happen.
  • We can expect extreme events – such as abnormally hot seasons and storms, to become more frequent in a warmer world.

The animations were originally developed by climateprediction.net  and The University of Oxford Department for Continuing Education (Technology Assisted Life-long Learning Unit).

BACK TO TOP