 who is Jackie Austerman from Lamont-Dority Earth Observatory and she'll be speaking on integrated numerical models with co-production to understand sea level change and its impact around Greenland. Thanks Jackie, over to you. Thank you so much. Yes, thanks so much for having me. I'm really happy to kick off the meeting today and talking to you about a project that we refer to as Greenland Rising. And as Greg just said, this is a project that integrates to American modeling and co-production to better understand sea level change and its impact around Greenland. And I hope that this topic speaks to the theme of this year related to surface processes, of course, most specifically sea level change, but also it has a very strong component of stakeholder engagement, communication and education. And I will talk about how these different components are interconnected today. This is a big four-year project. We are about a year and a half, a little over a year and a half into it. Of course, a year and a half, which one year was, and longer was pandemic times, which has affected the project in interesting ways and I'm happy to talk more about if anyone's interested. This is part of the NNA, navigating the new Arctic program at NSF. And it's a project that is run between the team at Le Monde d'Ordi Earth Observatory. And I'm showing you some of the PIs and students and postdocs involved here, as well as the Greenland Institute of Natural Resources. And again, I'm showing you some of the people of our Greenland collaborators. We've really done a lot of the on-the-ground work over the past year and a half. What I thought I'll do today is I'm gonna give, talk you through the motivation of this work while we're interested specifically in understanding sea level change around Greenland. I'll talk to you about the framework of what the different pillars are of this project and how they're interconnected. And as part of that, I'll show you some of the work that's been progressing and completed. This is a pretty big project. I'm gonna just give you a super high-level overview. And so I already apologized for glancing over a lot of the details, but I hope it still gives you a sense of the project. And of course, I'm happy to go into any more detail during the Q&A or later on. So sea level is changing around Greenland today for a variety of reasons. The Greenland ice sheet has been losing mass over the deglaciation and this losing mass today. As the ice sheet is melting, it of course adds more water to the oceans, which leads overall to sea level rise. However, close to Greenland, the sea level signal is quite a different one. And that is due to two components. One, as the Greenland ice sheet is losing mass, it's actually losing gravitational attraction that leads this ocean mass to move away in the ocean basins, move away from Greenland. This leads to a sea level fall close to the ice sheet. Additionally, as the ice sheet is melting, the solid earth is rebounding, which leads to an additional component of sea level fall. So overall, sea level is falling around Greenland. And especially this last component here, the questal rebound can be observed widely around Greenland. Here are some data from the North Eastern region and from the West Western coast. And all of these arrows show you the amount of uplift that is measured today. You see this is on the order of five millimeters per year to up to 30 millimeters per year of uplift, driven by past and present ice unloading. And that of course translates directly into sea level fall. So sea level around most of Greenland is falling due to glacial isostatic adjustment. So these processes I just described. Additional sea level change is caused by steric and ocean dynamics effects, as well as of course other ice melt. So if the ice sheet is melting on glaciers, I'm melting that effect screen as well, but to a smaller degree than GIA. And sea level is projected to fall on the order of meters by the end of this century. So pretty significant magnitudes. And this is really important for communities around Greenland. All of the communities that exist are on and along the coastline. They depend on the ocean for their transportation, for the infrastructure you see here in a picture of Asiat, which is one of the towns on the western side of Greenland. You see, for example, here some of these areas are quite shallow bathymetry. This is actually some of their oil and gas tanks that of course need to be filled up. So as sea level falls, a lot of this shallow bathymetry will become exposed, which affects their entire infrastructure. You also see where we have these squares here. This is where wastewater is directly transported into the oceans so they don't have wastewater treatment. These pipes just go into the oceans again as sea level falls. This is quite important, especially if you think about the winters when these areas are covered by sea ice. So they are really, really interested in sea level change and how it affects the entire infrastructure. Of course, additionally, these are communities where a lot of it is subsistence fishing and hunting. So it's not just for their transportation, but it's also actually for their food and nutrition that they depend on their waterways. So ports and water funds are a major part of their everyday life. So we want to understand what sea level is doing around Greenland, but we actually don't know what sea level is doing around Greenland, but we actually don't have a good understanding of that yet. On the left here, I'm showing you the tide gauge network and there's essentially no tide gauge on Greenland. There are some short, there's no long-term tide gauge on Greenland. There are some shorter term tide gauges to just measure tides, but not really good enough to measure sea level, long-term sea level trends. There was one in Nuke from 1960 to 2000 or so. That I'll come back to later, but there's no one that really contributes to the standardized catalog today. Additionally, the GIA component, so the component related to rebound and gravitational changes, is a component that we don't really do a good job in modeling today. So I'm showing you here a comparison on the left. This shows you the uplift from these GNAT stations. So from GPS around the island. So most of the constraints are really along the coastline. And then on the right, I'm showing you a model prediction of what uplift is predicted to be based on a GIA model. And this uses sort of a slightly older ice model, but the same differences persist to any of the ice models that exist for the deglaciation for Greenland. So there are differences in what's observed and what we predict. And these differences really hinder our ability to model sea level change today and in the future around the island. So what we want to do is we want to better understand sea level change around Greenland. And more importantly, we want to really understand how this impacts Greenlandic communities. And we want to produce science that is useful for the communities and also driven by the communities. And this project focuses on four different locations, three on the western side of the island and one of the eastern side. And the project kind of stands on three different pillars that are in part interconnected and in part evolve in parallel. The first pillar is community meetings. So for each of these towns and settlements that we are working with, we, and when I say we, it's really been our Greenlandic collaborators who've done all of this, the on the ground work because we haven't been able to travel. And in part it's also by design, I would say. So they have traveled to these different locations. I've by now traveled to all of the settlements on the western side of noob. And they do structured interviews with communities. They meet with the hunter and fisher organizations. They meet with the employees of the municipalities. They meet with community leaders. And their aim is to really get an understanding of the interest infrastructure. These aspects that I just told, talked to you about really understand which aspects they are interested in, which aspects they are interested in for their fishing and hunting purposes and get, do interviews of kind of the lived experience of sea level and ice change. And what we have heard from these, heard back from these interviews is that they have experienced seaways, shoaling and passageways that they've been able to go through in the past. They're not able to go through anymore. So they experience and see the sea level fall that is in line with our, our understanding. And the way this generally works is that they bring maps to these meetings and just ask them, learn from the communities what they know about the bathymetry so that it guides our understanding in which areas we need to focus on which magnitudes are important. The other component of the project is related to education. We have an outreach, I would say. We've done articles in the newspaper. We've done interviews on radio and podcasts. We've done, and again, I say we, but this is really our Greenlandic collaborators. You see one person you see probably a lot, which is here. This is Akaluk who's really been driving a lot of this effort. We've done STEM career talks where they have, so they are all Greenlanders and they've talked about their careers in the natural sciences to just humanize science and the natural science as can, and discuss them as possible career tracks. We've worked with them to create teaching materials, had participated in their classes, met with teachers, et cetera. So a variety of outreach events that I'm kind of just scratching the surface out, but happy to talk more if anyone is interested. And then the last pillar is, of course, the numerical modeling which is related to understanding the sea level change component. So far, this has been mostly focused on understanding, getting a better understanding of GIA. And these drivers explaining some of these differences between models and observations. We're starting to, starting up to also think more about the ocean dynamics and steric effects that contribute to sea level change around the island, but we're only really starting on that now. I want to highlight two studies related to GIA that I already have already been worked on by some of our students and postdocs. So this is a study here by a graduate student, Ralph Antwerpen. And what he looked at is, he looked at south-west Greenland here, and he looked at the ice retreat. So these different colors show you the ice margin and how it retreated over the deglaciation. And what you will notice here is that the ice sheet actually retreated past the present-day grounding line. The present-day grounding line is in, or the present-day ice margin, I should say, is in black. The ice sheet retreated past that ice margin and re-advanced over the Holocene. And it did so in response to slightly warmer temperatures during the Holocene thermal maximum. So what he wanted to understand is really better constrain how much the timing and magnitude of this retreat and re-advance. And what he did is he used GIA models that he forced with different ice sheet configurations and different amounts of retreat and re-advance and then compared them to a set of observations, specifically paleo-sea level data, present-day GPS uplift, and the one long-term tight-gauge trend that exists from Nuke. And what he found is that all of these observables are very sensitive, as you might expect, to the very local ice history. It's also very sensitive to the earth structure underneath, so the viscosity structure in the mantle. Nonetheless, in order to reconcile all of the data at the same time, he's found he's put some constraints on the timing of this retreat, as well as the magnitude, and specifically he found that timing was late on the Holocene and the magnitude probably smaller than what is shown here, so less retreat and re-advance. And it was exciting because this actually aligns with geochronology and ice sheet modeling results that had just came out this year. So this is important to both understand sea level today in this region, but it's also important to understand how susceptible this part of the ice sheet is to past warming and therefore possibly future warming. The second project on the numerical modeling side that I just want to highlight super quickly is a project by postdoc Andrew Lloyd. And he's looking at these differences in the GIA prediction compared to the GPS observations. And what he's testing is whether the difference in this model observation and the difference between the models and observations could be driven by variability and viscosity in Earth's subsurface. A lot of the GIA models assume that viscosity within the mantle just varies radially, so just varies with depth, but not within any depth slice. And of course we know that this is not true, but we don't really know the magnitude of viscosity variations super well. And it's also a lot more computationally expensive to do so, and that's why a lot of the models choose to only consider depth-dependent viscosities. He's testing whether this can explain some of these mismatches, and he uses a completely new approach to the GIA community, where he actually inverts for Earth's structure that is consistent with both of these, with paleo-sea level data and present-day GPS observation. And he has some exciting preliminary results that I don't have time to get into, but I'll keep an eye out for that if you're interested. So these are sort of the three pillars. They are connected through a variety of small aspects, but most importantly, they are connected through the new data that we are also gathering as part of this project. The first thing that we're gathering is new shallow water bathymetry and habitat measurements. So we have done in two of the settlements on the western side of Greenland. We've now done deeper water bathymetry measurements with multi-beam and backscatter to get it to have it better understand habitat. And then we are also doing the very shallow bathymetry just with a kind of handheld multi-beam and a zodiac as shown here. And you see some preliminary results from the processing of the bathymetry in one of the towns. The locations where we sample, the locations where we map is completely driven by what comes out of the community meetings, the areas that are most important to the community, and of course understanding the bathymetry is going to be really critical to combine with the numerical modeling because any projections of sea level change are really only meaningful if we know the bathymetry that sea level of wall exposes. The other data that we're collecting and that really ties in the different aspects is we're collecting new, we're setting up a new tide gauge network around the island at the four locations that I mentioned. This here shows, again, Aka Luke actually with a school class. So this is also part of ties into the education. We have educational tide gauges and sort of science research tide gauges. They actually did a science competition within their class to think about how to best install the tide gauge here. They have report sheets where they go back in intervals to look at the measurements. And we also, as I said, have the kind of research tide gauges which are installed here and they are the first high-precision type gauges installed by Greenlanders. And this is now at two locations. This ties into, of course, the community aspect where getting better tide estimates is important. It ties into the education and it very much ties into the natural science part as well since these are going to be really great constraints on the numerical models. So I'm going to end here this. I hope this gave you a quick overview. I know this was all very brief, but it gives you a quick overview of the different aspects of this project and how they are interrelated. And I am, thank you very much for your attention and I'm really happy to answer any questions. Fantastic. Thank you so much, Jackie. If you have a question for Jackie, you can either use the raise hand feature again. So under reactions, raise hand or post your question in the chat and we'll keep a look on that. I guess while people are collecting their thoughts, I have one question. I'm curious. So for the inverse modeling study you've described where you're trying to look at lateral variations in viscosity and how they could best fit the data. What are the sort of key data points that are the targets of that? Yeah. So the two main groups of data that we're using is our sea level data over the deglaciation. So these are both sort of sea level index points as well as marine and terrestrial limiting data. They, there aren't a ton of sea level data around Greenland. There are some though. So those are, that's one constraint and that's one of the constraints that has also gone in the past into reconstructing sort of past ice history in this region. And then the other set is the GPS uplift data that I showed on the earlier slide that we're trying to kind of simultaneously match. And the test is whether we can simultaneously match this with one earth structure, which has been proposed that it's not possible to do with a 1D viscosity structure. And so what this inversion is able to test is whether it is possible to do so with a 3D viscosity structure. Okay. Don't be shy. Otherwise I'm going to hog all the questions. You know, I'm curious too, whether they're good. Okay. From Allison. Go ahead, Allison. Thanks, Jackie. This is a very cool project to hear about. I'm wondering if you could just say a few words about how it came to be. And in particular, I'm thinking about how you forged these initial collaborations with the Greenlander community and scientists and outreach folks there. Yeah, that's a really good question because it, especially over the last year and a half, when we really weren't able to do any work on the ground and that is a big part of it, we really relied on having good collaborators in Greenland. And I think in part, I'm just going to go back to the project team slide, but in part we've got, I think really lucky with just the amazing team that we get to work with. And I think that's a really good question. I think that the connection was initially forged by, I think NSF organized a meeting. I want to say it was even in Greenland and Kirsty. Attended this meeting, which was organized from NSF to sort of foster collaboration. Between Greenland and, and American scientists. And that. That was kind of the initial, the initial connection between Kirsty and Carl. And that was actually how this project came about. It's kind of a funny story because we had, we had a postdoc who wanted to work with us guy, and we really wanted him to come. And so we thought we're going to write a grant to, to raise some funding and it spun into a much bigger project than we thought it would be. And we were surprised that it got funded because we kind of wrote it pretty quickly. And it's, and it's evolved much better than I had hoped at the time. But so it's, I guess a good point to put in whatever proposal you think might be, might be a good idea because you never know what gets funded. And this has really evolved in a project that I've learned a lot from in terms of working with communities and it's been super interesting to me.