Storms are one of the most dangerous weather events, causing havoc and devastation across large areas but how do they form? Join the Barometer podcast team as we guide you through a tangled web of duelling air masses, rotating spheres and stings in the tail. We also have an interview with Dr Clive Saunders from the University of Manchester, as he tells us about hail, lightning and more.

In the picture above, you can see a front that moved over the UK on the 3rd January 2012. The red circle shows the potential location of a “sting-jet”, which we discussed during the podcast. You can see some examples of time series of frontal passages from the Whitworth Observatory in Manchester from the 29th November 2011 (which we discussed on the podcast) and the 3rd January 2012.

Below are some videos that explain the “Coriolis force or effect” that we discuss in the episode. As you’ll gather from the podcast, it isn’t something that is particularly suited to an audio format!

Featuring: Will Morgan, Hugo Ricketts, Niall Robinson, Nicky Young, Kimberley Leather & Gary Lloyd

Interviewee: Dr Clive Saunders

Production: Gary Lloyd, Will Morgan & Nicky Young

Time for the third instalment of Niall’s video diary that he recorded in the field in Colorado last summer. This time he almost talks about science. Time to calibrate the eddy flux correlation time lag! It goes like this…

By knowing the direction of the wind and the concentration of something, we can work out the “flux”, that is, how much of the something is being emitted from the forest into the atmosphere (if the something is greater when the wind is blowing up the way) or how much of something is sinking from the atmosphere into the forest (if something is greater when the wind is, you guessed it, blowing down). The problem is, for the calculations to work we have to do this superfast - about 20 times every second.

We used a “sonic anemometer” which measures wind direction by detecting changes is the speed of sound between some little nodules: if there is a gust of wind, then the sound takes longer or shorter to travel over the same distance. At the same time, we are sampling air from right next to the sonic anemometer by sucking it down a tube. This goes to an instrument in the box at the bottom which makes measurements of the particles that are suspended in the air. The problem is that, because the air takes a certain amount of time to travel down the pipe before it is measured, there is a “lag time” between the wind measurement and the particle measurements. If we know this lag time then we can just shift the measurements so they match.

That’s where the balloons, cigarettes and a sharp knife come in. Cigarette smoke is made up of lots of particles. The idea is that we fill the balloon with smoke and pop it right next to the sonic anemometer and the particle tube. The sonic detects the pressure wave from the balloon pop (effectively a very small fast gust of wind) and the instantaneous release of particles is measured (after they’ve travelled down the tube) by the instrument at the bottom. We just need to match up the pop on the sonic with the particles detected after the tube and, hey presto!, there’s the lag time.

Here’s the second instalment of the Baromter Vodcast where we show you some of the experiments we were performing in the field in Colorado this summer. Tune in next time to see what I needed balloons, cigarettes and Stanley knife for.

In a first for the Barometer, we have both an audio version of the live episode as well as a video edition! Both can be found below.

The Barometer Podcast LIVE at Manchester Science… by TheBarometerPodcast

As part of the Manchester Science Festival, we’ll be producing our first ever LIVE edition of the podcast!!!

You can join us in a LIVE episode where we’ll discuss the differences, and similarities, between weather and climate. Come along to the Manchester Museum to hear about why it’s so difficult to predict the weather, how aerosols affect both weather and climate, and how clouds can affect climate. With live demonstrations and our version of ‘ready, steady, cook’ style voting this is an event not to be missed!

If that’s not enough to satisfy your thirst for atmospheric science and climate change then there’s the chance to explore Manchester Museum followed by Climate Change Question Time…live!

We really hope you can make what should be an evening full of fun and fascinating science. Let your friends and family know about the event too!

If you’ve got any questions for us then you can post them below the line. Also, we have a Facebook event set up so you can tell us you are coming or you could let us know on Twitter @TheBarometerPod.

Remember to get your questions in for the live event next month as part of the Manchester Science Festival!

What do you think of when you hear about atmospheric ‘emissions’? Typical responses include car exhaust fumes, smoke from fires, and volcanic eruptions. There are also emissions from power station chimneys, cattle, soils, and even plants which emit the essential element for sustaining life: oxygen. There are many more sources of emissions which can directly affect air quality, health, and climate but also indirectly through interactions with other atmospheric compounds.

Join us in this episode where we delve into the world of emissions and begin to unravel the complexity behind their evolution and mitigation. We’ll be discussing their physical definition, sources, and impacts. We’ll also be finding out how, due to sheer numbers, something smaller than a five pence piece has become the second largest natural source of methane after wetlands. The scale and importance of emissions is examined including how emissions from other countries, as well as our own, need to be considered when quantifying emissions and their impacts. Finally, don’t miss out on the interview with our special guest, Alice Bows, in part 2, who reveals the importance and influence of offshore emissions.

Planet Earth is like a discoball, reflecting and bouncing off some of the incoming sunlight back to space. The Earth’s climate and weather is driven by how much light and radiation is reflected and how much is absorbed and hence goes into warming the surface and atmosphere.

Join us this episode and hear all about albedo (which is a way of describing how reflective a surface is) and how that is linked to climate and climate feedbacks. Also don’t miss the interview with aerosol guru Prof Hugh Coe who explains how particles in the air can be both reflective and absorbing and how that makes it all more complex!

The above picture shows how some parts of the Earth’s surface or atmosphere are more reflective than others, e.g. clouds are bright, ice/snow (see Antarctica at the bottom of the image) are white and reflective, the desert and desert dust are brighter than the darker blue ocean and darker than the equatorial forests in Africa and South America. Just check out the massive big dust storm over the ocean off the coast of North-West Africa! The image gives a good impression of the mosaic of different brightnesses and how parts of that mosaic are constantly changing, with e.g. clouds, dust storms etc. forming and dissipating all the time.

Here are the links we mentioned in the news section of this episode:

Uniweather - UniWeather is not accessible to the general public at this time unfortunately. If you are a member of the university community and you would like access then please contact Dr David Schultz.

Satellite images of Chilean snowfall & Video of Chilean snowfall

Keep updated on the hurricane season at the National Hurricane Center

Above picture credit: NASA website

Featuring: Grant Allen, Will Morgan, Jennifer Muller, Hugo Ricketts & Niall Robinson

Interviewee: Professor Hugh Coe

Production: Jennifer Muller

Combating the effects of man-made climate change is seen as one of the greatest challenges facing us in the 21st century. Most ideas focus upon stabilising and then reducing the amount of carbon dioxide and other greenhouse gases in our atmosphere. We could achieve this by decreasing the amount of oil, coal and natural gas that we use by replacing these fuel sources with alternatives. In addition, we could also simply change our behaviour to facilitate less fossil fuel use. However, the pace at which we can make these changes is a topic of great debate. Scientists are now actively considering whether we need to take a more drastic route, where we artificially control the Earth’s climate using something called geoengineering. The aim of such an intervention would be to cool the Earth’s climate, in order to offset some of the warming caused by human activity. However, such techniques are not without their own risks and are highly controversial!

Join us in this episode to find out whether this idea is simply some science fiction writer’s failed plot-line, or something that could actually be used in the future to mitigate our continued fossil fuel use. We’ll discuss exactly what geoengineering is, why we might do it and the ethics surrounding it. We will also discuss a specific example, where natural clouds are modified so that they appear whiter, which potentially could cool the Earth.

Here is a picture of glass beads of different sizes. As we explained in the podcast, smaller beads are made of equally transparent material but the scatter light more, meaning they appear whiter. The same thing happens when particles are added to a cloud - more cloud droplets form and the cloud appears whiter, reflecting more sunlight to space and cooling the Earth. This is what is happening of the picture at the top of this post. The particles emitted by ships are causing clouds to form, leaving a trail along the ship’s track.

You can find out more about this idea on the BBC website and at the Royal Society website, which includes information on other geoengineering schemes also.

Below is a video discussion by two of the pioneers of the cloud whitening idea, John Latham and Stephen Salter.

Here is a picture that (is meant to) demonstrate the “Kelvin Effect” that Niall and Prof McFiggans were talking about. This the effect that gases find it easier to condense on a less curved surface (bigger particle) than a more curved surface The left hand particle is small and a molecule at the surface has less other molecules next to it. This means there are less bonds (three from its nearest neighbours) holding it there. The right hand molecule is larger and a particle at the surface has more bonds (four from its nearest neighbours this time). The molecule is bound more tightly so it is less likely to leave the particle and enter the gas phase.

Featuring: Niall Robinson, Jennifer Muller, Nicky Young and Grant Allen

Interviewee: Prof. Gordon McFiggans

Production: Will Morgan

Tornadoes are one of Earth’s most destructive natural weather phenomena, knocking over and sweeping up anything in their path. Their size, intensity and the path they travel over are unpredictable. With wind speeds ranging from 40 miles an hour to over 300 miles an hour, tornadoes are very difficult to study. However, many scientists have successfully managed to dodge lightning strikes and flying cows to record data to help better understand tornadoes. They have also captured some pretty spectacular images and videos.

Join us in this episode to find out what it is really like to be a storm chaser as we speak to Dr. Lindsay Bennett from the Institute for Climate and Atmospheric Science at the University of Leeds. You can find out more about the work in which Lindsay has been involved in her presentation here. We’ll also be finding out what tornadoes really are, how they form, and some interesting facts about which parts of the world they are found in. Visit The Weather Channel here for further information on severe weather as well as national and local weather forecasts, radar, and maps, and forecasts for world weather.

Below is a time lapse video of a tornado from the Weather Channel.

The is the second episode in our mini-series for Science Week, which is about how to make good measurements of weather. Meteorologists (that’s weathermen to you and me) have to try and do this all the time, to start the forecasts and to check they have worked. We give you our top tips for making decent measurements including:

• Temperature measurements have to measure the shade air temperature — don’t accidentally heat the sensor up with your hands, breath, the sun, building heating or anything else hot that isn’t shady air.
• Same goes for humidity measurement — don’t breath on them or you’ll measure the humidity in your breath.
• Wind sensors need to be in an open space, not behind a tree, a building, a budding meteorologist (that’s you btw) or anything that will change the wind.

GOLDEN RULE: make sure you are measuring what you are trying to measure, and not accidentally measuring the temperature of your finger or the moisture in your breath or something. Another thing to consider is how wiggly the thing you are measuring is. Forinstance wind data is wiggly because it gusts so its probably good to make a few measurements at a time and take the average.

In this special mini-series of the Barometer Podcast for National Science Week we’ll have a look at what makes a weather forecast good (or bad). How exactly do forecasts work anyway? Forecasts take a load of information about the weather right now, do a load of computer calculations and then try and figure out what the weather will be like in the future. But…sometimes forecasts go bad.

In the first mini-episode we talk about what can make or break a weather forecast. What if we wrongly measure the weather today and then use that to start the forecast? What if we misunderstand how the weather works and get some of the calculations wrong? What if something is important but so small that we don’t think about it? Bad forecasts, that’s what.

What does a bad fishing year off the coast of Chile have to do with weather over the rest of the World? Well, in a way, quite a lot. El Nino and La Nina are the Arnold Schwarzenegger and Danny DeVito of the atmosphere. These notorious weather systems of the Pacific Oceans that have knock on effects for global weather. You can find out some more about El Nino here and here. You can also watch a video of global sea surface temperatures here. You can see the heating and cooling with the seasons but can you also spot El Nino heating the east Pacific and La Nina cooling it? Watch out for El Nino in 1997-98 and La Nina in 1995.

A picture of “cloud streets” over the east coast of the US taken from a satellite. These are all the parallel lines of cloud starting over the Atlantic and running south-east. You can have a look at the NASA page here. They have happened because cold air has blown over the warm sea but there is a warmer air above those two layers. Convection gets set up in the bottom two layers but trapped when it hits the top layer. These convective cells seem to set up in long parallel tubes. This means we get shallow cloud (at the top of the second layer) along the side of the tube where the air has risen from the sea

And for those of you with a sharp eye - yes we have just learned how to put images in out posts

New episode recorded - post it soon.

Featuring: Grant Allen, Gavin McMeeking, Will Morgan, Jennifer Muller and Niall Robinson

Interviewee: Dr. Keith Bower

Production: Gavin McMeeking

More info:

Check out these links for pictures and to learn more about some of the aircraft we discuss in this episode: Dournier 228, C-130 (US), G-V, WB-57, ER-2, Geophysica, NASA Global Hawk, and the NASA Proteus .

And here’s our very own picture of a US Forest Service Twin Otter used to study smoke from prescribed and wild fires:

To make a wave cloud you need three things: a strong inversion, some wind and a hill or two. The radiosonde ascent shows that there is indeed a very strong inversion over the UK which is due to high pressure shown in the synoptic chart. The high pressure system is centred over the UK and as air rotates clockwise around a high pressure system in the Northern hemisphere this leads to Easterly winds over England and Wales. The Western boundary of the hills can be seen clearly in the satellite images.

This isn’t a particularly rare occurrence, but the conditions have to be just right. If you have seen some wave clouds let us know.

Merry Christmas and we’ll be back in the new year with another fascinating episode of The Barometer.