Archives for posts with tag: wetlands
A photo of wetlands from the flight featured in this paper. (Photo credit: Michelle Cain.)

A photo of wetlands from the flight featured in this paper. (Photo credit: Michelle Cain.)

Today, the MAMM team have had a new paper published based on one of our flights in July 2012. It’s quite exciting, as published papers are the end result of all our hard work, and the main way that others can find out about what we’ve been studying.

The paper is about emissions of methane and carbon dioxide from wetlands in Finland and Sweden, which is no surprise if you followed our field work! We used measurements of methane, carbon dioxide and the meteorology from the aircraft to work out how much of these greenhouse gases was coming off from the wetlands to explain the pattern we saw in the measurements.

This technique for working out the methane and carbon dioxide emissions compared really well with other methods we have of working this out from measurements on the ground or on towers just above the ground. This gives us confidence that the methods we have used are sound and the emissions we have worked out are good estimates.

We compared these emissions estimates with some computer simulations, and it turned out that our emissions were much larger than what the models simulated. This kind of comparison is a good starting point to try and improve the models and to make them more realistic, which is what we want if we are to use the models to try and test how much methane will be released under different conditions.

If you want to read the abstract and the full paper (it’s fully open access, including the peer review, which means anyone can download it), then head on over to the Atmospheric Chemistry and Physics journal:

O’Shea, S. J., Allen, G., Gallagher, M. W., Bower, K., Illingworth, S. M., Muller, J. B. A., Jones, B. T., Percival, C. J., Bauguitte, S. J-B., Cain, M., Warwick, N., Quiquet, A., Skiba, U., Drewer, J., Dinsmore, K., Nisbet, E. G., Lowry, D., Fisher, R. E., France, J. L., Aurela, M., Lohila, A., Hayman, G., George, C., Clark, D. B., Manning, A. J., Friend, A. D., and Pyle, J.: Methane and carbon dioxide fluxes and their regional scalability for the European Arctic wetlands during the MAMM project in summer 2012, Atmos. Chem. Phys., 14, 13159-13174, doi:10.5194/acp-14-13159-2014, 2014.
http://www.atmos-chem-phys.net/14/13159/2014/acp-14-13159-2014.html

This week in Kiruna, Sweden was my first field trip and first time north of the Arctic Circle. This time of the year there is 24 hour daylight, a stark contrast to the vision I had of Santa Claus’ home – who knew that in Lapland you have to pack sunscreen! It all makes sense if you think about the reason for the field trip, the wetlands, and how as the temperature gets warmer methane is released.

On Monday afternoon I had my first flight, and not only was the science experience great but the view was spectacular!

Wetlands out of the window of my first science flight (Photo: Ines Heimann)

Wetlands out of the window of my first science flight (Photo: Ines Heimann)

We flew two different low East-West legs from Kiruna over the Finnish wetlands (most likely the more brownish areas, see photo). What I did not expect was such a bumpy ride: even with very low winds, 500 ft above ground means lots of little air holes and little bumps! Luckily, one of the science aims was to profile up to higher altitudes, to assess the local atmosphere’s vertical structure.

Inside the aircraft. (Photo: Ines Heimann)

Inside the aircraft. (Photo: Ines Heimann)

Seeing the measurements in real time while flying is definitely a wonderful experience! It took a while to get my first plots working, but afterwards, every little variation I spotted in methane was a highlight. The flight for me was therefore not as “dull” as the Mission Scientist 1 (an old hand at this) called it.

An interesting aspect of the flights was the discussions over the headphones deciding whether to continue the planned flight or to change altitude to get a better idea of concentrations or fluxes.

The flying on Monday was followed by yet another first-time experience: flight planning for Thursday – no mean feat! The office space in a hangar did help to imagine a plane journey!

Inside the hangar, where our office was based. (Photo: Ines Heimann)

Inside the hangar, where our office was based. (Photo: Ines Heimann)

It is only when I helped produce a plan that I realised how much work goes into a successful research flight and a successful measurement campaign. I learned that weather is probably the most important but also variable factor.

Considering the rain, wind and cloud forecast for Thursday, we prepared two different sortie plans, considering timings, distances and the altitudes for the measurements to ensure the fuel would bring us back to Kiruna.

Unfortunately Thursday arrived with a near constant cloud cover making flying at low altitudes impossible due to bad visibility. We tried our luck and found a gap south of Kiruna and managed to fly a quarter of our flight track at the desired altitude of 1000 ft under the clouds. Lucky me, who took an anti-sickness pill before take-off!

A cloudy day for flying over the wetlands. (Photo: Ines Heimann)

A cloudy day for flying over the wetlands. (Photo: Ines Heimann)

The rain arrived soon after the first leg and we ended up profiling up and down the atmosphere searching for different methane layers transported from other regions and sources. Analysis will show whether we got lucky!

In conclusion, this week was full of interesting and fascinating new experiences, and showed me how exciting science can be and how much we depend on our environment!

Ines Heimann (University of Cambridge)

Thursday 19th September 2013, afternoon.

I am sure everyone who read my first post will be desperate know how my day turned out…! Well, somehow, my train arrived in Kiruna on time, despite setting off 1h45 late. And in a lucky twist, the ARA had taken off late and so landed late at 3pm local time. So James and Nicola picked me up from the station, and I got to the hangar at the same time as the aircraft. In another twist of fate, Seb who was on the afternoon’s crew list was not actually going to fly. So there was a space for me to fly! That shower and change of clothes would just have to wait…

Being the first science flight, we we all super-keen and there was an overabundance of mission scientists, meaning that as a lowly additional extra, I didn’t have anywhere to plug in my laptop from the seat that I was in. Alas, my laptop ran out of battery half way through, so I wasn’t able to monitor the measurements in real-time for the second half of the flight. As we were flying at low level for most of the flight, the seatbelt sign was on so I couldn’t even get up to charge my laptop elsewhere. Instead, I took lots of photos of the land that we were flying over, as (a) I was lucky enough to have a window seat and (b) the amount of methane coming out of the ground will depend on the vegetation cover, so it’s a useful record of that. (NB I haven’t got the time data from the flight as I write this, so I can’t link the photo times with their locations right now. If I have time, I’ll do that once I get hold of that information. It’s a bit too hectic in the middle of a campaign to get all the data in the right place – especially as I’m writing this in my hotel room late at night!)

Anyway, here’s the far-from-comprehensive story of the flight in pictures…

Our nominal flight plan, to give you an idea of where we were flying.

Our nominal flight plan, to give you an idea of where we were flying. We started and finished at Kiruna.

5pm (all times are Swedish local time). It's too cloudy to descend to minimum safe altitude. Just waiting for a break in the clouds so we can get down to near the ground.

1700 (all times are Swedish local time). It’s too cloudy to descend to minimum safe altitude. Just waiting for a break in the clouds so we can get down to near the ground.

1709: A mixture of forest and wetland areas.

1709: We managed to find a break in the clouds and fly down near the surface at minimum safe altitude. A mixture of forest and wetland areas.

1723: The seasons are changing near Abisko.

1723: The seasons are changing near Pallas, Finland. The orangey blobs are deciduous leaves changing colour. Beautiful!

1739: north of Pallas there are quite a lot of lakes.

1739: north of Pallas there are quite a lot of lakes.

1812: Much of the land further north was like this. Not sure what this beige coloured stuff is, but I shall ask around to find out!

1812: Much of the land further north was like this. Not sure what this beige coloured stuff is, but I shall ask around to find out!

1812: taken right after the previous photo, this darker wetland area was also widespread.

1812: taken right after the previous photo, this darker wetland area was also widespread. I wonder if more methanogens are present in one land type or another?

1834: After sampling the wetlands, we have ascended to above the cloud layer. Time to head home!

1834: After sampling the wetlands, we have ascended to above the cloud layer. Time to head home!

–Dr Michelle Cain, University of Cambridge

RHUL scientists Matthias Lanoiselle (L) and James France (R)  hard at work on the first science flight of MAMM. (Photo caption: Stephane Bauguitte and Matthias Lanoiselle.)

RHUL scientists Mathias Lanoiselle (L) and James France (R) hard at work on the first science flight of MAMM. (Photo caption: Stephane Bauguitte and Mathias Lanoiselle.)

Quick update on the first science flight, which took place yesterday (Thursday 15th August). We decided that all 6(!) mission scientists would go on this flight to kick off the campaign.

We flew north from Kiruna, out over the ocean to about 73N. We flew through some clean background air (not recently polluted), and also some layers of air that had higher and more variable methane concentrations. We saw these layers 3 times at similar altitudes, and I think there were 2 distinct sources for this higher methane. We’ll need to look at the back trajectories and carbon isotopes (see this earlier post for info on what they are!)

On our way back south, we flew over Berlevaag (in Norway), where Dave Lowry was on his road trip, taking air samples. We didn’t see him from the aircraft, but he saw us!

We also saw some methane when we flew low over the forest/wetland areas. There was a clear transition between low methane over the rockier/drier areas near the northern coast, and the greener areas further south. Both Nicola and I also felt a transition between feeling fine in the north, and feeling rather queasy flying over the wetlands, where there’s a bit more warmth and a low rumble of turbulence…

Flying over methane-emitting regions of Finland. 18:43 on Thursday 16 August 2013. (Photo credit: Michelle Cain.)

Flying over methane-emitting, nausea-inducing regions of Finland. 18:43 on Thursday 16 August 2013. (Photo credit: Michelle Cain.)

While most of the MAMM team toil in the heavens above, fighting wayward coffee mugs as the pilots roll and pitch, some of us are down below in the murk, feeding poor undernourished boreal mosquitoes and moose flies.

Beavers logging in a bog

Beavers at work, logging for dam-making in Saskatchewan, late July 2013. Depend on it, the mosquitoes are there! And so is the C-12 enriched ‘light’ methane. (Photo credit: Mary Fowler, University of Cambridge.)

What we are trying to do is discover the carbon signature of the wetlands. Northern wetlands make a great deal of methane, but so do other northern sources like gas leaks (some of the world’s biggest gasfields are north of the Arctic circle) and also the methane hydrates that have recently been in the news.

Each individual methane source has its characteristic carbon signature. Carbon has two stable forms – Carbon-12, and the slightly heavier Carbon-13. There is also the rare radioactive for Carbon-14, used by archaeologists to date old relicts. Biological processes favour the 12 form, which is slightly easier to incorporate into biological molecules. Each time biology cycles carbon, the organic matter becomes progressively richer in carbon-12 and poorer in C-13. When finally the biological carbon is returned to the air as methane bubbles, it is highly enriched in C-12. Conversely, carbon-13 is richer in methane made by inorganic processes like fires, or in gas released by geological heating or from coalfields.

Thus if we sniff the air, we can tell where the methane comes from. Is the methane biological? Then it is relatively rich in C-12. Or is it geological or from a fire? Then it is slightly heavier in carbon-13.

Moreover, we can back-track the winds, by running the weather forecast computer model backwards. For example, if we sniff C-13 rich air in Ireland, we can track the wind back to a fire in Quebec. Some years ago, ‘heavy’ methane arrived in New Zealand. The air had passed over the Indian Ocean, and had last left land as far away as Mozambique. That’s where plumes of smoke carrying C-13-rich methane had been picked up. So the Methane C-13 sniffing near Wellington had actually smelled grass fires in southern Africa.

But to do this we need to measure exactly what the typical C-12 and C-13 fingerprints of each major methane source are. That’s difficult, because they vary. The sources are quoted in differences in per mil numbers compared to a relatively C-13 rich standard. “Per mil” is like per cent, but per thousand, and is written as ‰, where negative values are light, and very negative values are very light. Thus northern wetland and swamp methane can be very light, ranging from about -60 to around -70‰, while methane from fires or coal mines can be much heavier (less negative), around -25‰. Cow breath and landfill methane are between these extremes, often between -50 and -60‰, as is gas from the big Siberian gasfields.

For example, if we sniff unusually high methane in the wind, and work out the signature of the increment, we can figure out what type of source it came from. Then we can back-track the wind, and try to pinpoint the source. For example, if in summer an easterly wind arrives over Spitsbergen that is loaded with methane whose carbon is -70‰ we can often backtrack the wind to the swamps and wetlands of western Siberia. But in winter, that same easterly from Siberia could have methane whose carbon is -55‰, showing it came from the gasfields around the Ob River estuary. This methane ‘telescope’ – maybe ‘tele-rhino’ would be a better term (far-nose) – is excellent for figuring out who made the gas.

But to do this, we need to measure the sources. And the biggest northern sources are the wetlands in the boreal forest and bogs. How do we measure them? –We get down low and murky in the mosquito-infested swamps, dodge the bears, wolves and moose, and come back with plastic bags and steel cylinders of air. We take long poles, carrying hoses connected to a little pump, and collect cushion-size bags of air. Some samples come from low down over the swamp, while other samples come from holding the pole high into the wind, so we get a spread of values. The best sampling is done over 24-hour periods, at 2-hour intervals, including warm afternoons when the air mixes, and cold dawns when the still air is rich in local emissions. And at 1am is when you are likely to meet a wolf, or a reindeer, or bears (especially in Canada, where they also do a mean line in moose). All the time the mosquitoes attack, and the bugs grab flesh and gorge themselves. If you don’t crawl into camp with a face and arms bitten to look like red bubble wrap, you haven’t been working. And there’s no sleep in a 24-hour effort, just half-dozes between sampling alarms, while eternally slapping off the biters.

Then, after checking we haven’t sucked in any mozzies, we ship the samples back to the lab to analyse. If our samples have a range of methane contents, we can then plot a “Keeling plot”. This is a graph of the C-12 to C-13 ratio in the methane against 1/methane concentration, the reciprocal of the concentration. If you plot up a lot of points with variable C-12:C-13 and concentration, you typically get a nice straight line. On the axis, where 1/concentration is zero (i.e. source concentration is infinite), the intercept of the line gives the C-12:C-13 value of the typical source.

In the 2013 summer campaigns, we’re measuring swamps in a variety of places. Dave Lowry is driving across northern Sweden and Finland, mapping out the methane concentration and C-12 to C-13 ratios across the source areas. Rebecca Fisher is working in swamps, bogs and fens around the Abisko National Park in north-west Sweden. Euan Nisbet and Mary Fowler have just come back from a major field trip across the muskeg of Canada, in northern Ontario and northern Saskatchewan, in collaboration with Environment Canada, to characterise the C-12 to C-13 signature there, and will now cross the wetlands of Sweden and Finland just north of the Gulf of Bothnia. All of them will be generously feeding the bugs with excellent new bites.

Up in the air, James France, Rebecca and Dave will be in the plane, collecting air samples. Mathias Lanoisellé, recently back from a Atlantic boat profile, will be helping.  By comparing the C-12 to C-13 ratios in methane from the airplane samples with the C signatures  measured on the ground, and by back-projecting the wind movements of the air masses that have been sampled, we can figure out what the sources were.

For example, both in previous work and in 2012 flights to Spitsbergen, we determined that the summer methane source in the easterly air was almost entirely from wetlands. Compared to background, the high summer input of methane that came from the east (northern Russia) was almost all biological, from swamps. This was at a time when the gasfields were at a low ebb, and luckily there were few fires. The result meant that other more geological sources were quiescent.

One inference from this is that there was very little methane input from decomposing methane hydrates. Since hydrate decomposition is not seasonal, then if large hydrate inputs were absent in summer they were likely absent in winter too. Of course that may change, and our winds came from central northern Siberia, not the far east, but we found no strong hydrate signal. Hydrate methane emissions have been much in the press recently, but they’re shy in the Arctic wind.

Now has anyone got any anti-histamine?

Professor Euan Nisbet, Royal Holloway University of London

…will be the blog of the MAMM (methane in the Arctic: measurements and modelling) project. Check out what we did last summer by looking at this interactive map (click on the MAMM check boxes and info buttons) or last year’s blog posts (the link is to the first of several consecutive posts). We shall be back here in July 2013 for this summer’s campaign.

The research aircraft flying over wetlands in Finland in July 2012.

The research aircraft flying over wetlands in Finland in July 2012. (Photo credit: Nicola Warwick, University of Cambridge.)