Friday, 29 August 2008

Paint the whole world with a Rainbow

When you have lots of sunshine and showers around like we’ve had recently (well OK we’ve had more showers than sunshine) then it’s ideal conditions for rainbows. We see rainbows when the sun shines through the raindrops. More precisely the sunlight is refracted in the raindrop and is split into the different colours that make up the sunlight – you might remember doing something similar in the school science lesson when you shine a bright light through a prism (a glass pyramid). The refracted light is then reflected off the back of the raindrop at an angle of around 42o, which defines the angle in the sky that we see the rainbow. The blue light is a shorter wavelength and so is refracted at a bigger angle than the longer wavelength red light, which means that in the bow you see the red at the top and the blue near the bottom.

Sometimes you can see a secondary rainbow and I’ve included a picture above I took of a primary and secondary rainbow this year in Cornwall. The secondary rainbow occurs when the light undergoes a double reflection in the raindrop. Because this is a second reflection the colours occur upside down compared to the primary rainbow, and they are dimmer. We call the area in between the two bows Alexander’s band after the ancient Greek Alexander of Aphrodisias who wrote about it. It is possible on very rare occasions to see a third bow, but as by this stage the light is very dim and it appears in the direction of the Sun it is extremely difficult to spot.

There are a few different mnemonics that help you remember the seven colours of the rainbow, but my favourite is ‘Richard Of York Gave Battle In Vain’ – that’s Red, Orange, Yellow, Green, Blue, Indigo, Violet.

Rainbows have been talked about for many years. The ancient Greeks wrote about rainbows as a path made by Iris (the messenger of the Gods) between heaven and earth. Chinese mythology speaks of a slit in the sky sealed by the Goddess Nüwa using stones of five different colours. The Bible in the story of Noah talks about the rainbow of a sign from God that life would never again be destroyed by floods. But perhaps the most famous is that the Leprechauns keep their pot of gold at the end of the rainbow. Unfortunately you will never reach the end of the rainbow for two reasons. The first is that because it’s an optical effect then it moves as you move and so you can never reach the bottom. Secondly, and perhaps more importantly, a rainbow is really a circle, it’s just that we see half of it.

There are two things that stick in my mind most about rainbows. The first is the fantastic painting by Constable of Salisbury Cathedral from the Meadows. I first saw it in the National Gallery, and read about the painting of it in a great book by John Thornes (called John Counstable’s Skies, which I can definitely recommend to you). My second abiding memory is from the Wordsworth poetry I studied at school. His 1802 poem "My Heart Leaps Up When I Behold The Rainbow" begins:

My heart leaps up when I behold
A rainbow in the sky:
So was it when my life began;
So is it now I am a man;
So be it when I shall grow old,
Or let me die!…

Wednesday, 13 August 2008

How do I follow a career in Meteorology and do I need a degree in Meteorology to become a Meteorologist

Download Paul's BBC Radio interview on careers in meteorology

With exam results out and lots of young people thinking what they might do next, we thought it would be a good idea to say a bit about how to become a meteorologist. You can’t do a GCSE or A-level in meteorology so what should you be thinking about choosing to study?

Well, many people who end up in Meteorology come from a science background and in particular have studied subjects such as Maths, Physics and Chemistry at GCSE, A-level, and for a degree. Increasingly there are organisations that are employing people from backgrounds in environmental science and geography, but often there will be a requirement to undertake further studies to give people the scientific background needed, whether working as a meteorological researcher or an operational forecaster. Check out our ‘Spotlight on Careers’ page to see how just a small cross-section of our community ended up in meteorology ‘’.

Very few Universities offer Meteorology degrees, but there lots of related courses that will equip you well – and a number of MSc courses that give an opportunity to convert over to meteorology if you feel you would like to understand more about the science. The Society accredits Undergraduate degree and MSc courses and you can find a list on our website at ‘’.

I’m conscious that I am biased, but meteorology offers some great career opportunities, often involving travel within the UK and internationally – meteorology is a very international community. You can work as:
• an operational weather forecaster – and there are many facets to a role like that, including TV and radio presenters if that’s something that interests you.
• a weather observer - either taking observations or working in the development of instrumentation from simple rain gauges right through to aircraft equipment, weather radar and the development of new satellite technologies.
• consulting services - which is an increasing area of growth within the community that brings in business skills to provide advice to companies whose bottom line is affected by the weather.
• research scientist – either working in a university group or at one of the UK’s meteorological research institutes and centres, working at the forefront of weather and climate science.

You can find out more about the range of employers across both the public and the private sector in our section about ‘Who Employs Meteorologists’ (

For those working in meteorology already we also offer Vocational Qualifications and you can find out about the NVQs/SVQs in weather forecasting and weather observing, and how to become a Chartered Meteorologist at ‘’.

Tuesday, 12 August 2008

The Planning for our Climate Change Question Time

We are just in the final planning stages for this year’s Society event at the British Association’s Festival of Science – a Climate Change Question Time. The Festival moves around the country and this year, in part I suspect to mark its status of European City of Culture, we are in Liverpool.

In preparation for the event we did some filming on the streets of Liverpool in late July, asking members of the public about climate change. I have to say that we had a very warm and friendly welcome and we collected quite a number of excellent and interesting interviews which we hope to be able to put up on the Society’s website before the end of September. We will be using a small selection of these to open our Question Time event. I promise to put a link to these in my blog when we have them ready as I know that you will enjoy watching them and hearing what people have to say – I am sure you will find that many of their thoughts and questions are similar to the ones you have.

The event will be in the style of Question Time and we are delighted to have a panel of very distinguished and internationally respected meteorological scientists who have been very actively involved in, amongst other things, the work of the Intergovernmental Panel on Climate Change (IPCC). The panel includes:

• Professor Sir Brian Hoskins, Director of the Gratham Institute for Climate Change and a newly appointed member of the Government’s Climate Change Committee;
• Dr Peter Stott, the Head of Climate Monitoring and Attribution at the world renowned Met Office’s Hadley Centre, and a lead contributor to the IPCC’s Fourth Assessment Report;
• Professor Jo Haigh, Professor of Atmospheric Physics at Imperial College, whose area of expertise includes the Sun’s impact on our climate;
• Professor Piers Forster, the Roberts Research Fellow and Professor of Climate Physics at the University of Leeds, working in the field of climate forcing and feedbacks.

The aim of the event is to allow members of the public to ask the questions directly of the scientists that they want answered about climate change. The event will be followed by a reception where people will be able to meet with the members of the panel on a one-to-one basis and also see meteorological experiments demonstrated by the Society’s school Met Ambassadors.

It’s a meeting open to the public and if you would like to come we would be delighted to see you there – we are in the Quaker House (22 School Lane) in Liverpool city centre from 6-8pm on Tuesday 9 September. There is a small charge on the door, but if you register with us in advance (with Sue Brown at or on 0118 956 8500) we will be able to provide you with a ticket for free entry. You can find out more details of our and other Festival activities at ‘’.

Monday, 11 August 2008

What is it about Young People and Umbrellas?

On Thursday evening last week it was absolutely chucking it down. I was checking the weather radar to plan my best time to make a break for home and realised that I wasn’t going to get away with it – so I got out the umbrella and headed off.

I just couldn’t believe how many people were walking around just getting soaked because they didn’t have an umbrella. Now this is where I’m going to sound a bit like an old fogy, but there were all young people! My very unscientific survey suggested that 100% of people over 60 were brollied-up, some 50% of 60-30 year olds (of which I fall into) had umbrellas, but to my great dismay, not a single young person was carrying an umbrella (excuse my arbitrary definition of ‘young’).

So when did it become uncool to carry an umbrella. I was trying to think back to my younger days and whether I carried a brolly around with me. I did, but I then realised that this wasn’t much help as I could never have been described as cool.

Is the answer that we need Apple - the makers of the iPod and iPhone – to design the new iBolly or perhaps persuade Posh and Becs to carry around one of our Society unbrellas (which by the way are very reasonably priced for that special someone in your life). Or should we resign ourselves to the fact that the younger generation would rather be at one with the elements that be seen dead carrying one of our most British of traditions – and to think, they will never have that life experience of getting half way home and remembering that they have just left there nice new umbrella on the bus.

Friday, 8 August 2008

Weather, Smog and the Beijing Olympics

Since Henry Des Voeux allegedly invented the term Smog (an amalgamation of smoke and fog) in 1905, it hasn’t been in the news as much in the UK since the 1950s. Perhaps the most infamous being the Great Smog of London in 1952, which is said to have resulted in over 12,000 deaths, and led of course to the introduction of the Clean Air Act in 1956. Those kinds of smogs were the result of heavy coal burning in factories and homes, but modern day smogs are a little different.

These days smogs are more often a result of industry and transport emissions, and have two parts to them. The first are emissions of the Oxides of Nitrogen, Volatile Organic Compounds and Carbon Monoxide; the sort of thing Councils measure in those road side cabins that you might have seen. These are the primary pollutants, but there are also secondary pollutants caused as a result of sunlight reacting with the primary pollutants to create Ozone at ground level. Ozone is good for us up in the atmosphere because it protects us from harmful sunlight, but down at ground level it’s bad for us to breath. All of these primary and secondary pollutants combine to give us what we call photochemical smogs.

The big cities of the world do suffer from these kinds of smogs, like Mexico City, LA, and of course as we’ve seen on the news recently Beijing. And it’s not good news for those with breathing difficulty or those athletes who have to compete in those conditions.

It’s not the only challenges that athletes will face. August is one of the warmest and most humid months in Beijing with temperatures rising to 30oC and humidity as high as 75%. This can have two effects. Sweating cools us down because when the sweat evaporates from the skin it uses heat to turn the liquid into a gas and leaves the skins surface much cooler – we’ve all experienced that when we’ve got out of water before we’ve had the time to dry off. The high humidity reduces or can even prevent the sweat from evaporating. We sweat more and then end up very dehydrated. The second problem is that as our body temperature rises we push more of our blood towards the skin surface where it has a chance to cool, and away from muscles and body organs and we start to feel tired – and in extreme cases can lead to heatstroke.

We can’t do much about the temperature and humidity, but what about the smog. Well unfortunately that’s affected by the weather as well. Taking cars off the road and closing factories to reduce the emissions will certainly help, but if they don’t have the right kind of weather, then it will take a while for the smog that’s there to disperse. At this time of year when the upper parts of the atmosphere are warm then this can stop air rising and taking pollution away – it acts like a kind of lid to trap in the pollution. On a positive note though, because of the high temperatures and humidity there is a chance of thunderstorms which will help to wash out the pollutants.

Good luck to China for a great games and best of luck to Team GB – bring back lots of medals guys. By the way when are they going to make weather forecasting an Olympic sport!

Wednesday, 6 August 2008

St Swithin’s Day and Flooding

Since I last blogged I’ve celebrated Yorkshire Day (on 1 August) and perhaps more meteorologically relevant St Swithin’s Day on 15 July. I’m sure you know the old saying that if it rains on St Swithin’s Day, then it will rain for 40 days and nights afterwards.

The saying comes from the story of the much loved Bishop of Winchester. As a man of the people he asked to be buried outside, where people could walk on him in the wind and rain – and in 862AD that’s what happened. But juts over 100 years later some monks decided to move St Swithin to a resting place inside the cathedral but the move was delayed by 40 days and nights of rain, supposedly St Swithin himself weeping in displeasure.

I read that the saying has been tested 55 times in the past and on none of the occasions when it rained on 15 July did it continue to rain for the next 40 days and nights – but it makes a nice story.

The day after St Swithin’s Day I was in London at a dinner with Sir Michael Pitt and Lord Chris Smith (the new Chairman of the Environment Agency), very appropriately talking about flooding, and more precisely the implementation of the recommendations from Sir Michael’s report on the floods of 2007. The report is very well considered and, I think, one of the best reviews for Government I have seen in a long while and stands a real chance of making a difference to the management of flood risk in the UK and importantly the effect on people’s lives and property.

There’s one part in particular that I think is well overdue, and that’s the greater coming together of our weather and flood prediction work with the Environment Agency and the Met Office working more closely on both their research and operational programmes – potentially through a joint centre.