Tuesday 29 January
Fire map from NASA on 29 January 2019 https://firms.modaps.eosdis.nasa.gov/
Today’s morning fires survey team are just on their way back from the airport. Yesterday’s flight was great (apart from the fiery temperatures in the cockpit and a very bumpy ride with the strong daytime turbulence/thermals). We sampled a mix of mile-wide flaming and smouldering fire lines in the north of Uganda with varying CH4/CO2/CO ratios and some interesting fire tracers reported from other instruments, sampled by flying along-wind and across-wind at heights between 1000 ft and 6000 ft above ground. We were joined by a couple of flocks of black and white birds at 3000 ft that passed the window rather fast… Much like the Senegal surveys, there was a thick regional haze from the fires and a faint smell of smoke for the whole flight.
Flight track from the north Uganda fire survey
We collected bag samples on each pass through the plumes for isotopic analysis and much of the material burning was low-level scrub and papyrus. The land was very dry (much drier than this time last year) and there were many tens of small and large fires in view from the horizon at 3000 ft, most of which appeared to be managed land clearance. The data collected on these flights will improve the knowledge of the isotopic signatures of biomass burning from these plant types in this region, which will better refine models that use isotope measurements as constraints on emission source regions and source types.
By Grant Allen
Saturday 26 January
Flight C129 – Lake Wamala survey and sampling the plume downwind of Kampala
This morning, the aircraft did a repeat of yesterday’s flight plan over Lake Wamala and downwind of Kampala. This gives us another chance to examine the methane emissions from the lake and surrounding swamps (which I think are papyrus swamps like the ones we saw at the nearby airfield the other day), which also might have been polluted by some small fires dotted about the place, and to look at a more complex mix of pollutants coming from the capital city. The FAAM aircraft has done flights like this downwind of cities like London and Lagos, so it will be interesting to see what we find here. Everyone I spoke to seemed very happy with how the flight went, as collecting good data is what we are all here for!
I wasn’t on board, as I’m going back to the UK tonight after nearly a week here. It’s a shame I only got to do one flight, but this is not that surprising given how uncertain it is doing field work in a country that we have never worked in before. You need to build in a lot of contingency for these things, and me having only one flight is not even close to being a factor in our plans. I came along to help with the heavy workload of planning and flying during an intense campaign, so hopefully the others who are staying for another week or more will have been able to pace themselves a bit more than they would otherwise. You can’t really have scientists working long days every day for weeks on end – it’s not healthy even if it’s just for a short time in the field. It also helps to have extra people on hand in case of illness. We have been putting 3 mission scientists on the crew list but flying just 2 of them. This means that if one of us feels even a little ill, they can stay on the ground without any problem with having the right passes sorted out for the airport in advance. This is working really well, as it’s fairly common to get a tummy ache on campaign in tropical regions, and nobody wants to be on an aircraft when that happens!
Just resting our eyes in the operations centre for the field campaign
I’ll miss the excitement of the field campaign when I go back to the UK, as you don’t get the same insight into every aspect of the work from afar – like discussing options for upcoming flights based on how the weather forecast is developing over breakfast, finding out the latest instrument issues or breakthroughs at lunch, or mapping out that future Nature paper over a Nile Special lager and curry in the evening. There is so much value to be gained from going on a campaign that I am extremely grateful I was able to take part. I will continue to send in forecast maps that I have set up with the Met Office for the campaign to help with the flight planning, and keep tabs on what’s going on, but I will really miss the random chats I won’t have with all the great people working on this project. The campaign hasn’t even finished, and I can’t wait until the next project meeting comes along!
Tue 22 January 2019
Having planned out the next few days flights – to lakes/wetlands as well as fires – and with no point refining the plans based on the weather forecast because we don’t know exactly when we will be able to start flying, I’ve joined Rebecca again to do some air sampling. This time with intent, and with a full rucksack containing anything I might need (unlike yesterday).
We are currently in a taxi out to see a contact, Steve Forsyth, who works at Mission Aviation Fellowship – Uganda, and is based at an airfield by a papyrus swamp. MAF is an organisation that operates small aircraft to transport refugees from nearby countries like the Democratic Republic of Congo or Sudan. The swamp will be a source of methane and so will be a good opportunity to work out the carbon-13 fingerprint of such an ecosystem. The principal investigator of this project, Euan Nisbet, has sampled here before, so it will be good to find out whether the fraction of carbon-13 varies over time or is very consistent.
Getting out of the conference room is a good chance to stop obsessing over ever evolving weather forecasts and see some of Uganda. And I can make myself useful by taking photos of the sampling location at very least.
We are on the way back from the airfield now. It was completely surrounded by papyrus swamp, which meant we could access it quite easily. We were escorted around the airfield by Ivan, who was essential in helping us not get our feet wet (we were not keen to lose a trainer in the swamp!) while getting as close to the swamp as possible.
The papyrus plants were extremely tall in places – close to 4m probably. Some areas were cut down to the stem, and they grow back in about a month according to Ivan. The stems themselves are very strong, and are excellent wind vanes of you ever are in need of one. Which I did, as I was taking wind measurements to accompany the air samples.
In all, we took 13 samples from locations close to the surface of the water up to about 2m high, all around the edge of the swamp, plus one background sample further away from it. This will allow us to find out the carbon-13 fingerprint of this papyrus swamp, where there were the highest methane concentrations. For example, the papyrus that was cut down to ground level may emit more or less methane than the fully grown area and maybe the measurements will give us an indication of that.
Filling a bag with air from near the papyrus
Sampling above the swamp
Methane was bubbling up through the standing water
A papyrus swamp was on the other side of the fence
Novel wind direction observation using a stalk of papyrus
Simultaneous air sampling and meteorology observations