The Planet Earth podcast - 'Testing satellites on Earth, hedgerow wildlife'.
14 February 2012
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Sue Nelson:Hello, I'm Sue Nelson and welcome to the Planet Earth podcast, which this time is from the RAL space test chamber in Oxfordshire, and in front of me is what looks like a cylinder covered in Bacofoil but I'm assured that it's far more state of the art than that and you can find out what exactly it is in just a moment. Also in this podcast we will be looking at why it may be better to cut your hedgerows less frequently than you might have thought.
Dr Jo Staley:If farmers cut their hedgerows every three years that can have a substantial benefit for wild life. It results in more berries being produced for over wintering birds and small mammals to feed on and also in more flowers being produced in the spring for pollinating insects.
Sue Nelson:More on that story later. Now, the RAL space test chamber. RAL stands for Rutherford Appleton Laboratory and with me is Dr Hugh Mortimer who is the Space Scientist here with a specific interest in the environment and before we find out exactly what that connection is describe to me what this - I rather rudely called this giant cylinder cover in Bacofoil actually is, but let's face it that's exactly what it looks like isn't it.
Dr Hugh Mortimer:Yeah it is. Essentially what we're doing is we're standing outside the test chamber which is where we calibrate tests for space instrumentation, both satellites and smaller instruments before they go into space. So, what we have is a facility that allows us to take the pressures and temperatures down to such an extent that we're representing, recreating the conditions in space, and one of the things you alluded it to, are instruments being covered in Bacofoil it's not too far from the truth. Essentially what we have are instruments protected by the thermal radiation from the sun and from the moon from heating our spacecraft up or our spacecraft cooling down to temperatures that would mean that our mechanics, our electronics would no longer operate.
Sue Nelson:Now you're specifically interested in sea surface temperature, why is it so important to measure this accurately?
Dr Hugh Mortimer:The Rutherford Appleton Laboratories has been sending instruments into space to measure sea surface temperature since the early 80s. That gives us a continual data record of temperatures which we can then use to identify trends within the climate and we can use them to look at different aspects such as climate change and how the sea is warming up.
Sue Nelson:Now you're involved in an instrument that going to fly on board a satellite for this. Whereabouts do we get to look at that?
Dr Hugh Mortimer:The instrument that we are calibrating is a large European space agency project, this is the fourth in the generation of the same kind of instruments that we've flown before and within the next few years it will be launched and operational and it will be providing data for the scientific community both for operational purposes, so for the Met Office, for providing weather forecasts because essentially the temperature of the ocean really drives the weather that we get in Europe. The other thing that we're trying to do is then use this data to look at climate change and climate records. So the instruments that we're developing and building here we're then calibrating before it gets launched into space and therefore we know precisely how accurate that instrument at measuring sea surface.
Sue Nelson:Well it's great to be able to get effectively a sneak preview of something that you're working on - a prototype effectively - it's in a different laboratory just behind the test chamber.
Wander past the side of the test chamber there with a rather marvellous view, past another clean room with people wearing those unflattering hairnets and around a corner and into Hugh's laboratory.
Dr Hugh Mortimer:So we've just walked into the molecular spectroscopy facility and within this facility we have the ways and means of calibrating ground based instrumentation.
Sue Nelson:It always looks far more low tech than it does, I think, a real science lab. It's sort of Wallace and Grommet nuts and bolts style thing. Don't look horrified, but that's how it always appears to me.
Dr Hugh Mortimer:Well where we are is a very used laboratory. We use spectrometers primarily to look at the differences in light interacts with materials around us, both solid, liquids and gases and what we're doing is then we use that information to give us, essentially, data on how much gas is present or the equalities of that particular gas. So, here in this laboratory we also have something called the sister instruments, which is the scanning infrared sea surface temperature radiometer.
Sue Nelson:And sister actually goes on board a ship doesn't it, the Queen Mary II.
Dr Hugh Mortimer:We're very privileged to have this collaboration with Cunard where we're able to launch, essentially, and put our instruments on the side of this really prestigious beautiful ships where we can measure sea surface temperature in exactly the same way that the satellites measure sea surface temperature and from which we can then take the instrument that we know very well, that we've calibrated at the labs and then cross compare the sea surface temperatures as the satellite passes overhead on the Queen Mary II.
Sue Nelson:And how accurate have they been?
Dr Hugh Mortimer:Our instruments can measure to an accuracy of about 10 milli kelvin which is pretty accurate.
Sue Nelson:So that's 0.001.
Dr Hugh Mortimer:0.001 kelvin.
Sue Nelson:Why put it on a cruise ship, effectively, what not a research vessel?
Dr Hugh Mortimer:Well one of the benefits is that we get to use a very stable platform. We also can operate it in a very clean condition and we are subject to temperatures because the Queen Mary II goes around the world which are very, very cold, so we're looking at very northern latitudes to very, very warm, so we're looking at the tropics as it travels around the Caribbean for it's very rich passengers. Currently sister is on board the Queen Mary II so she's not actually here in the laboratory - I think she was in Cape Town earlier today cruising around, so she's now on her world voyage and we won't see her again until late April.
Sue Nelson:I assume there are no scientists on board that cruise ship.
Dr Hugh Mortimer:There aren't, no. We've made, unfortunately, the instrument fully autonomous so it's very rare that we get to go on board. Generally it is in berth at Southampton.
Sue Nelson:That was a bit of a design blunder on your part. So, where do we go to see your instruments?
Dr Hugh Mortimer:Okay, we can go through to this laboratory over here and now we're in the heart of the spectroscopy facility itself. So, what we're looking at are two very high resolution spectrometers, one is used for measuring solid phase materials, aerosols, dust and the other one - a much higher resolution spectrometer - it's about half a tons worth of equipment, that's used to measure gases. We look at pure concentrations of materials such as methane, carbon dioxide, water vapour and then we can look at how the light interacts with those materials and those gases to actually change the light as it passes through. The spectrometers that you see here are even more complicated than how the instruments in space work. So, the instruments in space looks at specific wave lengths of light, so essentially it's just a detector with a filter on the front of it and it just measures certain bands of light. The spectrometers can break down those bands even further. So essentially they can look at different wave lengths across the spectrum. So the wave lengths that the radiometer will be looking at, both the radiometer in space and the radiometer, the sister, they will be looking at very specific wave lengths while these instruments are able to measure different components, not only temperature but also how that radiation is affected by the gases and the materials it interacts with.
Sue Nelson:And the spectrometer is...I always think of it as like the work horse for space science and astronomy - it's used on virtually every single space mission you can get and it also has its importance for ground based experiments, particularly with environmental science.
Dr Hugh Mortimer:Yeah, that's right. The spectrometer, the ones we look at in the intra reds, they work also in the UV and in the visible and they really underpin a lot of the knowledge that we have about the world about. It allows us to see in depth where our eyes can't view, essentially. They allow us to probe the interaction between radiation and the gases that you can't see with your eyes. Because these instruments work in the infra reds they get to understand the impact of how light absorbs thermal radiation and then how it emits thermal radiation. So, essentially looking at the climate change effect, the climate greenhouse gases and how that thermal radiation is actually stored and then omitted in different wave lengths.
Sue Nelson:Dr Hugh Mortimer from RAL space, thank you very much.
In England alone there are 450,000 kilometres of managed hedgerows. These hedgerows, many of which are made of hawthorn, are often called corridors for wildlife, be it beetles, birds, butterflies or dormice. Most farmers trim their hedges every year but new research about how to manage hedgerows most effectively has discovered that less frequent trimming of hedgerows is better for wild life. The study, part of ongoing research by DEFRA and Natural England involve Dr Jo Staley from the Centre for Ecology and Hydrology and independent hedgerow consultation, Nigel Adams. I met up with Jo and Nigel at one of the sites by a bare hedgerow on the Waddesdon estate in Buckinghamshire. Jo began by explaining how often most farmers currently trim their hedgerows.
Dr Jo Staley:Farmers who are part of the Stewardship Scheme, the agri-environment schemes are asked to cut their hedgerows either every two years or every three years depending on which particular option that they've signed up for.
Sue Nelson:And how often are you recommending that they should cut their hedges?
Dr Jo Staley:The research that's just been published shows that if farmers cut their hedgerows every three years that can have a substantial benefit for wild life. It results in more berries being produced for over wintering birds and small mammals to feed on and also in more flies being produced in the spring for pollinating insects.
Sue Nelson:How significant an increase in provision for the wild life was there?
Dr Jo Staley:Well we were comparing cutting every two years or every three years with cutting every year, which is the sort of standard practice for farmers who aren't in these agri-environment schemes and we found that particularly the cutting every three years has a huge benefit so we're finding three and a half times as many berries as on the plots that were cut every year and we're finding twice as many flowers as on the hedges that were cut every year. The plots that we cut every two years had a sort of intermediate benefit, but there we were finding that the timing of cutting was absolutely critical, so in order for their to be an advantage to cutting every two years in terms of increasing berry abundance these hedges really have to be cut in late winter rather than in the autumn. So the hedges are there during the winter at the critical time when the wild life needs them. But they key thing about this is that we're providing that evidence that wasn't therefore before, so that means that if policy decisions are going to be made they can be evidence based.
Sue Nelson:And what sort of knock on effect then would this have on wild life that use hawthorn hedges.
Dr Jo Staley:We're hoping that by increasing resource provision that this will provide more berries for over wintering birds and small mammals that really depend on this for survival. We know that with a lot of our farmland bird species, the thing that we find is their population sizes is actually over winter survival rather than breeding success. So, having these resources in the winter are really absolutely key.
I've just stopped a couple of over wintering lady birds here that are hiding in a crevice in the hedge, so that shows how even some of the more common species do rely on the shelter of hedgerow during winter.
Sue Nelson:Let's go through to the unmanaged bit - oh yes, are they sloe berries?
Dr Jo Staley:That's right. So these are blackthorn berries. We're standing next to a bit of a hedge here that hasn't been trimmed, so this is the bit that will be cut next year as part of our three rotation and there's a nice patch of sloes here which are still providing foods for and for small mammals that want to come along, especially on a really frosty day like today they may not be able to get into the ground to search for worms and things so that's when these berries become really important.
Sue Nelson:Nigel Adams, you're a hedgerow consultant, you were involved in selecting some of the sites that are being used to extend the project. For you, is this a sort of vindication of what people - and there are a great number who appreciate the benefits that a hedgerow can bring, but through better management can actually approve it.
Nigel Adams:Most certainly. If we start at the point that hedgerows are one of the most important and understated habitats in the whole of the country really, and yet if we cut them every single year at the same height we are liable to destroy the potential that they have so this research, as Jo has said, is looking at two year and three year cutting - not only for the over wintering fruit and berries but even the blossom in the spring is very important for invertebrates populations as well, so it's crucial. We only have to have a look at hedges that haven't been trimmed for years and the vast amount of berries that are on them and the flocks of redwings and fieldfares that come down on them in the winter to see that something is going on. So we're just trying to encourage farmers not to trim every year, but so much money is being spent on this policy of giving farmers help towards that, that we need to get that right and we need to look at whether perhaps if we're trimming every two years that we trim in September immediately after the harvest of that second year when the ground's dry and the farmers want to get and they've got an opportunity to get on the field, get it trimmed and that's it, is that money well spent because of course they're taking off that fruit potential for the over wintering bird right there, so we've got to know whether that is working or do we need to go into the three trimming, and we need to look at autumn cutting against late winter cutting, those sort of things are very important.
Sue Nelson:Jo, describe what sort of a hedge we're beside here at the moment on the estate?
Dr Jo Staley:We're standing next to a mixed species hedge - it's a beautiful frosty morning. This is fairly young hedge that was planted at some point in the 1990s, probably under the Countryside Stewardship Scheme.
Sue Nelson:And when you say a mixed species hedge, what species are here? I can see catkins, I'm not sure if that's attached to the hedge or not.
Dr Jo Staley:Yeah, so we've got some hazel in this hedge. We've got quite a lot of hawthorn, some blackthorn and we've got some other species which are maybe less common in some of the hedges - so we've got spindle, dogwood-
Sue Nelson:Looking at Nigel there - has she got it all right Nigel?
Nigel Adams:Yes, it's a typical mixed species hedge. There a bit of maple as well. The trend these days is to plant mixed species hedge because they provide so much more diversity and habitat really.
Sue Nelson:Jo, is this part of extending the research as well because the five year research was done purely on hawthorn hedges so I assume you are hoping for the same sort of results.
Dr Jo Staley:That's right. Well, as you say the five year research was done just on hawthorn which was the dominant hedgerow species, so it was important that we looked at that initially. We're now looking at a range of different hedgerow types, so here we've got the fairly young hedge that was planted under the Countryside Stewardship. We've got a site in Devon which is a typical mixed species hedge on a bank there and that's a fairly old hedge. We're also looking at a dominantly blackthorn hedge and two other, mainly hawthorn hedges, so we're trying to extend it to a wide range of hedgerows and also different geographical sites across England.
Sue Nelson:Nigel, when an organisation like Hedge Link receives effectively backing through scientific research where a certain way of management is beneficial for wildlife, does this make it easier for you to advise people in terms of how to manage their hedgerows or do you find that people don't want to know. It's, sort of, well it's their hedges; they trim it, job done.
Nigel Adams:I think it's a delicate balance. You certainly do need the scientific backing and the facts about what you're doing, you just say well this works and this doesn't work, but also pure science can sometimes turn landowners off, dare I say, in the sense that they want a practical way of doing things and practical outcomes so you have to tie the two things together, from very practice advice but backed by good science I think really.
Sue Nelson:Nigel Adams and Jo Staley on the benefits of cutting hedgerows every three years instead of one or two. Incidentally, the extended research project is also examining the effects of incremental hedge cutting to two by just 10 centimetres each year.
I'm in the laser spectroscopy lab of RAL space with Dr Rebecca Rose and Dr Damien Weidmann because they've both developed a prototype instrument for detecting atmospheric gasses, and Damien I'm going to begin by asking you what this instrument is called primarily because I want you to say it and not me!
Dr Damien Weidmann:It's a laser heterodyne radiometer.
Sue Nelson:And what does a laser heterodyne radiometer actually do?
Dr Damien Weidmann:Basically all molecules in the atmosphere have a specific signature, what we call spectral signature and by looking at this we can actually identify and measure them remotely, so this instrument is actually decomposing the light coming from the atmosphere and finding out where are these specific signature corresponding to atmospheric molecules.
Sue Nelson:And which gas and which molecules in particular are you interested in looking at Rebecca?
Rebecca Rose:We're interested in lots of different gases, so the instrument we just tested is detecting ozone, nitrous oxide, methane, water and CFC.
Sue Nelson:Are there associated colours with each molecule, because when you hear about auroras and green associated with oxygen...
Dr Damien Weidmann:They are but not for human eyes. We are operating in the middle intra red so that is radiation that human eyes can't see, so everything is invisible.
Sue Nelson:What makes your instrument different to the ones that are around and already measure these gases?
Rebecca Rose:Our instrument can be made to very small, lightweight and compact. It's also very high resolution which means that we can look at very specific target gases. A lot of these gases impact the global warming or health issues.
Sue Nelson:If you've got an instrument then like this that's smaller than normal, Damien, then that makes it ideal for deployment in satellites. What sort of missions in particular are you hoping to get this instrument on?
Dr Damien Weidmann:Missions which would be similar to some which have already happened in the past with some larger instruments and one of them is, for example, NEPAS, it's a really bulky big instrument - something like 400 kilos and we would like to demonstrate that our instrument can do similar work that's 2 kilos or even less kilos. So, missions which would look at the global coverage of, for example, methane or ozone or the sort of atmospheric gasses which are relevant for climate change and studying the climate system, that's the sort of thing we would be able to do with a space based instrument.
Sue Nelson:It has been tested hasn't it, Rebecca, and how did it go?
Rebecca Rose:It went well and we were able to detect five molecules - water, methane, nitrous oxide, ozone and CFC.
Sue Nelson:It did exactly what you wanted it do it.
Rebecca Rose:Yeah and from the [spectra s.l.] we recorded we were able to obtain information not just about how much of the gas was in the atmosphere but also where in the atmosphere it is, so the altitude at which it's concentrated.
Sue Nelson:So that's a pretty good result then Damien. So what next?
Dr Damien Weidmann:We are currently working in detecting the [unclear 0:20:17.9] the instrument even further which would make it about 10 x 10 cm and working also on miniaturising the electronics to make a very small instrument ready for deployment. There are a couple of satellites that we can use to demonstrate technology in space and if we have a small and light payload we would be able to have a first demonstration in orbit within a couple of years.
Sue Nelson:Well good luck with it. Dr Rebecca Rose and Damien Weidmann from RAL space, thank you both very much indeed.
Do remember to check out our Facebook page and you can follow up on Twitter, this has been the Planet Earth podcast for the Natural Environment Research Council. I'm Sue Nelson, thanks for listening.
