Unravelling Martian Methane Mysteries in the Canadian Arctic

An image of our ABB methane detector deployed at Gypsum Hill on Axel-Heiberg Island in Nunavut. Alex's work here showed that the variability in a measured methane signal might be able to tell us more about our distance from the source than the total amount of methane does. This is important for how we might prospect for methane seeps on Mars. 

Oh, and look at that view!
Sometimes it's not just the results of our investigations that take our breath away.

by Alex Innanen

Almost three years ago now (and wow, time really flies) I spent three weeks in Nunavut, which you can read all about here. I talked a little in that post about why I went up and what sort of work I was doing there. But the work did not end when I landed back in Ottawa (or got back to Toronto after an extended weekend at the cottage). No, I then spent the next several months going “I guess I need to write this up in a paper somehow.” This was complicated by a few things – the fact I hadn’t ever written a paper based on fieldwork (nor read many), the fact that the results were not super clear cut, and some good old fashioned procrastination. But I ended up presenting the work a few times, including at my yearly research evaluation meetings and at a couple conferences, and it started to come together into some kind of story.
 
When I took methane measurements, I let the instrument ingest the air passing over for ten minutes, and the instrument took a measurement every second over this time period. This meant I ended up with what I took to calling a ‘spiky plot’ of hundreds of methane measurements over that ten-minute period. I noticed two things in these ‘spiky plots’. The first was that I could find the average methane concentration over that period, and that the average methane concentration tended to be highest right next to the source of the methane and drop off as I moved away downwind – typically the way you expect methane (or any gas) to work, which if nothing else meant the instrument was working. The other thing I noticed was that the variation in how spiky the spiky plot was was also higher right next to the methane source. That is to say, the methane signal varied over a much larger range when I was closest to the source, and had a much smaller range further away or upwind of the source. You can see this in the three graphs below which I took at one of the springs.

Three spiky plots. You can see that the upwind measurement has not only a lower average concentration (dashed line) but also is much, much less spiky (solid line) than the other two. Note that the y-axis is much larger on the 'Inside Wolf Spring' measurement because I saw such huge spikes of methane!

I saw this same phenomenon with the variability getting higher closer to the source even when I wasn’t moving in the exact same direction as the wind. At Wolf Spring I only moved in a (mostly) straight line in the wind direction, but at Gypsum Hill I took two sets of measurements – one along the wind direction, and one at a diagonal to the wind direction. This second set of measurements suggested that getting more data at various locations around the methane source could give us a clearer understanding of how methane behaves in a two-dimensional grid around such a source.

To that end, I sent the instrument back up to the arctic last summer in the company of an MSc student from McMaster with detailed instructions to get me a grid of measurements around Wolf Spring. My procrastination had achieved one thing – I was able to add this new dataset into my paper. And I’m glad I was! From the 2024 measurements I was able to see to impact both distance from the source and the angular distance I was from the wind direction had on the methane signal. (I’ve visualised the geometry simply below in case it’s not clear what I mean, where θ is that angular distance from the wind direction.)

Now, in 2022 I did not have any way of accurately measuring the wind direction. Instead I used a technique which is actually similar to how the Phoenix Lander did it, wherein I held up a roll of flagging tape and watched which way the wind blew it. In 2024 we were a bit more high-tech: the master’s student had access to a small weather station which gave me actual numbers for my wind direction. Knowing the position of the instrument at each measurement and the wind direction at the time of the measurement, I was able to get the distance from the source (d) and the angle of the instrument to the wind direction (θ) and combine these (d/cos(θ)) and compare this value to the average methane concentration and the variability in the measurements. I found that both fell off with increasing d/cos(θ) (or distance from the center of the methane plume), but that the variability actually fell off in a slightly more predictable way.  

Okay, you may be thinking, this is all mildly interesting but what does this have to do with planetary science? Well, as has been discussed on this blog before, there’s a lot we don’t know about martian methane. One of the unanswered questions is where it’s coming from – both in the sense of what is producing it, but of more interest to this work, the actual location from which it is being emitted. We know that we see methane plumes on Mars, but we don’t know how long they last, how the behave or, again, where they’re coming from. If we did send an instrument to Mars to investigate this, we could use what I learned in the arctic to determine what that instrument should look like and also how we should use it to find the source of these methane plumes.

I learned that the variability is a better indicator of how close we are to a methane source. The variability I saw in my spiky plots is over very short timescales, thus our hypothetical instrument should be able to make high frequency measurements to capture changes over these short timescales. I also learned that knowing the wind direction is pretty important, so our instrument should be combined with some kind of wind sensor. My measurements were taken from various locations around the methane source, so having our instrument on something that can move like a rover (or even a drone!) may be more useful than if the instrument just stands still.

There’s more I could say about this, but I don’t entirely want to spoil my paper (coming soon to an Acta Astronautica near you!). Even though it took nearly three years, it turns out there was quite a bit to learn from a few slap-dash methane measurements in the very distant north. 

To read the paper, visit: https://www.sciencedirect.com/science/article/pii/S0094576525003212

Poster Sessions and All That

An image (Figure 1, courtesy of Elisa) of one of the many buildings which housed the 2024 American Geophysical Union Conference in December of last year. The conference is massive, overwhelming even! Yet, it provides a venue where even disciplines with small numbers of scientists can meet and discuss their science. From Elisa: "There was no mistaking this was the place. So many poster tubes and people piled up waiting for the light to change."

 by Elisa Dong

Going to conferences… is fun! 

The attendance at conferences is a significant part of a graduate student experience. These are the places where we showcase our work, get feedback, and check out what’s up and coming in the field. Sometimes, conferences take place at exotic locales, and sometimes, they may be as mundane as “the place near the airport that is extremely inconvenient to take public transport to.” AGU 2024 fell somewhere in between, in Washington D.C., capital of the United States of America.

Given that the flight time and drive time were not too dissimilar, my boyfriend and I opted to drive down to save on costs, a very real consideration for going to conferences! While unplanned, we drove through some fascinating geological features going through Pennsylvania, dotted with various electoral signs on the way down. We stopped at a fairly mediocre cash-only brunch place, and saw snow and horses for most of the way down. Entering the city, the traffic went from a quiet one lane drive to cars changing lanes without signals, and mysterious roundabouts with confusing signage. Once at our hotel, we spent half an hour figuring out the parking situation, grabbed some food downstairs (with the best free bread we had ever had), then promptly went to bed. 

AGU is about a 5 day conference (see Day 1 in Figure 1!), and I had a poster on the first day and a presentation on the third. My presentation went well, and I was able to touch base with a coauthor of mine to confirm a few key concepts for a paper I was writing (I did this by tapping his shoulder to say hello). I had thought I would have the entire last day off to wander the city. As it turns out, there was an entire session dedicated to planetary defense and impactors that I had missed in my schedule, so I slunk back into the conference center to hear about the modelling work that was ongoing (Figure 2 shows once of the very few photos I took at the museum). 

Figure 2. Ducks at the museum! I also took photos of many many rock displays, but the local fowl section was also very cool!

It’s worth noting I met up with several other colleagues who do similar things – checking on some scientific concepts that were their specialties, sharing ideas for future works, and generally touching base. Despite running around to sessions, visiting random posters, picking up free ducky keycaps, the networking and chatting with more distant coworkers and future collaborators is one of the best things about a conference for me. Getting on a zoom call or sending an email is just not the same. 

The collaborative and productive nature of conferences was really highlighted by the poster I had up. I made the questionable choice of wearing heels that first day, anticipating being able to sit and walk around. Unlike some other conferences I had attended in the past, this poster session was huge. Having mine on the first day, I didn’t realize just how well attended it would be! 

So instead of being able to kick back and look at other posters during my session, I was glued at my poster well past the closing time and completely missed seeing an old colleague just a few posters down the aisle. I received a large amount of feedback, including kind critiques and thoughtful questions that have lingered as I consider the limitations of my work. Folks stopped by to offer resources and model simulations, encouraged me to bring up my work to a larger group (this has happened! I gave a presentation and received more positive feedback and further suggestions), and all the good stuff. I met many new people, whose names I wish I had taken down, including some who might be future reviewers of my work that gently pointed out the critical questions that I might want to consider as I continued working on the project. I explained a few concepts to a child attending the conference with family, and shared in their excitement over the awesomeness - that modelling that can help us explain our real-world observations. 

I was also happy to meet up with my previous supervisor and bring him up to speed on what I was working on, and to hear his assessment of the current state of his field and view of the conference.
Some cool things I got out of AGU 2024:

• An invitation to ask about a summer internship position (this didn’t end up working out, but it definitely expanded my thoughts)
• Meeting undergraduate students! It’s always a delight to see what cool things they’re working on, and we’ve spoken again since about work related matters
• A suggestion to present my work at an internal MSL meeting despite not working on data from the team directly
• The potential for writing a paper for a special edition (this also didn’t work out, but the procedure has been established and might be something to touch up again in the future)
• A visit to NASA Goddard! I’ve never been to a NASA Centre before, and I was able to plan it with one of my coworkers based out of there and get approvals just in time! It was great to see what folks are doing behind the scenes, the huge clean rooms with possibly over a hundred HEPA filters installed (Fig. 3), and the old-fashioned, yet extremely functional, measuring tools they used
• A late night ice-cream hangout with an online friend who forewarned me about the roundabouts
• More ice-cream and a super toasty paper fill menu on a busy Friday night when every other place was packed
• An experience (and the post-experience) at Coffee Republic. I have never enjoyed ads in my inbox so much before. The food was delightfully greasy, the coffee solid, and it was fun to hear the workers chat about their relationships candidly
• Going to the Christmas market! Two of them even!
• Barrel and Chuck, the two plushies I picked up on the way back at a Cracker Barrel. (Barrel is the lab’s new emotional support capybara, and has a lavender scented heat pack inside him! All of us in the office where he lives happen to like lavender, so it works out great. He occasionally moves from desk to desk to provide extra support)
• And, an incredible amount of useful feedback for my own work + inspiration from other projects in the future!

Figure 3. The HEPA filter wall. Incredible. What else can you spot in the room?

AGU is one of the stranger conferences out there. It is a huge conglomeration of what is really 30+ conferences that are distantly related all mashed into one location. While it makes it easy to pop into a session about say, climate change or quantum physics, it’s not necessarily planned out in a way that potentially related sessions don’t interfere. Add on thousands of attendees, and you might be feeling a bit claustrophobic and getting more exercise than planned as you trek from one building to another. Something to keep in mind. It may be better for some folks to target more niche conferences to get the same return.

We drove back as well. My eyes are still recovering from being blasted with 8 hours of dry air.