Hello, and welcome. My name is Marcel Nicolaus. I'm a sea ice physicist at the Alfred Wegener Institute here in Bremerhaven. My research interest is mostly the radiation budget of snow and sea ice in the Arctic, but also in the Antarctic. I'm working with a remotely-operated vehicle under the ice and its autonomous stations drifting around in the ice. In MOSAiC, I'm involved since the very beginning, so almost 10 years now, and I'm leading the ice team. My personal questions here is, how do snow and sea ice make it through the seasons, from the winter, through the spring, all the way until the summer when they might leave the Arctic landscape full of melt ponds, and even melting away? With these observations, what are the processes behind it? How do these processes interact today and how might that change in future? When I talk about sea ice, or many people talk about sea ice or the pack ice, often the snow is not really considered although there's no rules,. There's no rules, many of the processes that we study and usually connect them to sea ice. Snow has more extreme physical properties. The solar installation is stronger, the optical properties, let's think about the albedo, dominates the pack ice properties. All the surface properties, the melt ponds, in summary, come up in everything that we see from airborne or satellite missions. First, sees the surface, first sees the snow. Obviously, snow itself has mass, but it also, through its other properties, strongly controls the sea ice mass balance, and as a freshwater medium, it's unique in that system. That's why when we talk about sea ice research should always extend it to snow and sea ice research, which we do explicitly here in MOSAiC. Sea ice and snow are the central elements of the Arctic climate system, not only because they sit between the atmosphere and the ocean, but in particular because they integrate the big fluxes from the atmosphere and the ocean and in-between, small differences have huge impacts for the snow and the ice cover. When we study the sea ice, we're in strong interactions with the atmosphere team for all the fluxes and exchange process at the surface and the ocean team, there's all the exchange process at the bottom. The biogeochemical work strongly focused on the exchange of gases and particles with the ice and through the ice. We're best friends of the ecosystem because these studies a habitat because sea ice it's a habitat not only on the surface, in particular in the ice and under the eyes for small microorganisms and algae. For MOSAiC, the sea ice is also of a particular interest because this determines many things of our project. This is what the main flow is made of, sea ice and snow. The sea ice and the snow will also then in the end, control the drift trek of the entire project. When we talk about sea ice and Arctic's and climate change, everybody has heard about shrinking sea ice. Yes, that's right. The sea ice is getting less, it's getting less extended, it getting thinner since volume changes and the extent. But beyond that, and that's probably as important, it gets younger. The times of the big and multi-year pack ice rigidly Arctic are over in most areas and it's only a small region that still has it. It's becoming increasingly dynamic this younger and thinner ice and reset to transpolar drift changes. As a consequence, all the interactions in the Arctic between the atmosphere, the ice, and the ocean change. Also, the interactions between the physics, the ecosystem, and the [inaudible] processes change over time. Knowing about all these changes, we can easily identify the needs that we have for MOSAiC. We certainly need to better quantify and understand these processes with all these linkages. We have to bridge the scales from the microorganisms to the Arctic basin because they impacts on all these scales. Finally, we will improve our forecasts, but not only for the snow and ice cover, but for the entire Arctic climate system. A lot of our scientific work is not only related to the measurements we are doing now, but also ready for planning of the experiment because the ice will determine the drift. So we worked a lot on retracting ice drift of the last years to find the perfect or the optimal starting position. It was a lot of scientific support and planning needed to plan the ice camp and the area around it with a distributed network. We were studying the genesis of the sea ice before it now became all ice. So what is the history of the ice? When did it form? Where did it come from? All this is the basis in the end now for the experience ongoing. In addition, here at home, we have additional possibilities to satellite remote sending data and through their forecasts to support the teams in the field to help their decisions and reserved also to understand the system a little better. So what's the particular about the ice work in MOSAiC? What do we want to achieve? First of all, it is the big time series. Have a consistent dataset of all our key parameters for one year, being consistent in the method, and also in the data handling. But we also have to focus on the new aspects compared to other studies. So timely foci, the snow on sea ice to bridge between the different scales or to focus more on interdisciplinary work instead of having multiple expeditions going in parallel or one after the other. There are many of the first things in MOSAiC. But being the first is not necessarily unique, but to connect all these first things into a unique product, that's what we're aiming for here. For example, if we talk about the links between the field observations and the models, we do not want to generate a dataset that might be used some day somewhere in the model but we want to have a direct immediate interaction already now and we started to implement that. In the end, the ice work is only one small MOSAiC piece in that big climate study. When we talk about key parameters, what are our snow and sea ice parameters? For the snow, it's obviously the thickness, the mass, and distribution. So simple question, how much snow is there and where is it, and when is it there? If you look into the snowpack, what does this sum figure for you? What are the properties of all these layers? In particular, what is the property of the surface because that determines the albedo, the roughness at that scene from all the satellites? In the sea ice, again, the question is how much ice is there? But then look into the ice, also stratigraphy, the ice properties. What is lives in the ice? What are the optic properties of the ice in summer? How does the entire ice pack move later and through the year through the arctic? What flow sizes, for example, are there? is it many small one, big one? How does that affect the surface and the bottom topography of the ice pack? In summer, melt ponds, might it be before ice or snow, but they are most characteristic and a key topic of sea ice team. With all that, we have the connections to the atmosphere and the ocean and wit that to these teams that study these spheres in more detail. In addition to having this unique time series of all the parameters, we have different four key and different seasons. Obviously, solar radiation fluxes don't play a role in winter. But therefore in the beginning of the experiment, the sea ice, the young ice, the very dynamic ice, has it on challenge and one studies the dynamic snow the first leg in particular. In spring, this sum comes back. So snow plays a big role, but at the same times, leads and ridges will shape the landscape beyond the original formation of sea ice. Then obviously the big summer topic as melt. What do you sea ice and snow leave in terms of melt ponds and how much of the ice makes it through summer, and how would the refreezing look like in autumn again? All our time series and also the seasonal foci is they're interrupted by what we call events. Events in the ice team and for most other teams are in particular, storms, leads, and ridges. Because if a storm passes by the main ice camp area, it probably has very different effects depending on the season when it happens. When a storm comes, it changes the snow accumulation,it moves the ice around, it will exactly formed or often at least form these leads and ridges. But what happens to a lead or ridge in these different seasons will be very different. In winter, a lead rapidly refreezes and forms new ice. In summer, it might suppose the breakup of the ice. In winter, the ridge piles up. In summer, the deformation event may also just help to deteriorate a ridge and let all the ice blocks fall into into the sea. So events have to be planned in, but we never know exactly when they might appear. Depending on who you ask in our ice teams, the scales are very different. Some are really interested into very small in ice microstructures. Others look with satellites onto the ice landscape and wonder how important that is. But in the end, and that makes MOSAiC again, unique, we have them all on board. We have people that dig into this snow and into the ice on the millimeter scale or even beyond, and we have people that operate the biggest zoo of remote sensing operation centers on the ice. In between, we do transact over the ice to understand our flow better, we do dives is the ROV system under the ice maps, the ocean ice interface. We fly with helicopters and drones over our ice camp and connect to the distributed network and the tens of kilometers around. But we also big spring airborne campaign that flies aircrafts all the way from the land, from the Arctic shore to our ice camp. As of today, we are a four month into the experiment and leg 1 and leg 2 are mostly completed. So what did these first two lines give us? First of all, we established the ice camp. If you look to the map, every single dot, every square on this map stands for one measurement, for one deployment, for one project. They are all somehow connected. So we are successful in establishing this camp, and now we want to maintain and extend it over the next legs. So we have not only set it up, but you also measure the first four months of data. So we have four months of Arctic winter data of all our key parameters consistently measured as planned before. But we also experience strong ice dynamics. If you look, for example, to these radar images here, we can see a seven-and-a-half by seven-and-a-half kilometer footprint of radar with smooth areas in gray and the bright areas are rigid and deformations. We can see how around the ship that ice moves, pilots are bridges, relocates, and comes back again. We experienced the first storms and ridge events and we now have an idea how these look in winter, and we are curious to see how they look in spring and summer. For example, we were able to obtain a 3D image of all flow mapping with an ROV from underneath mapping with a laser scanner from the surface and if you repeat that a couple of times through the year, we'll also see how all this ice scape and landscapes joins in 3D. To sum it all up, what will the ice work in MOSAiC result in? First of all, we will get that unique dataset, time-series and dataset for generations. It is the time series, it is the most comprehensive and best plan time series that we have, and there's nothing comparable. Based on that, even after we left, the ship will work on this dataset for decades and we'll have to continue then the collaboration in order to provide new insights into the processes, to bridge the scales across the Arctic, and across all disciplines. Then with that , we'll elevate our understanding of the Arctic climate system and finally, also improve our predicting capabilities. Last but not least, thank you for your attention and your interest in our work. I'll be happy if you would like to join more of our work through all the channels that you might know.
