Katabata project's scientific model validated by Southern Greenland surveys
The climate simulations envisioned by the researchers of the ULiège Katabata project have just been validated by the data transmitted by the three weather stations installed in Southern Greenland in July 2020. The results of the analyses go one step further and now show that the katabatic winds recorded in the summer in Greenland could compensate for part of the lack of wind recorded on the European continent. Establishing a wind farm in this region could ensure the stability of the electricity supply system in Western Europe. This study is published in the International Journal of Climatology (1).
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ossil fuels emit greenhouse gases and pollution that contribute to global warming. It is therefore urgent to find sustainable alternatives. However, the renewable resources that we could tap into are not evenly distributed across our planet. Countries with a high energy demand do not always have the renewable energy resources to meet their demand within their territory. This is the case with wind, an abundant renewable energy source that is not evenly distributed in space and time across the globe. In Europe, for example, during the summer, there are much weaker wind periods than in winter. This phenomenon is likely to become even more pronounced with climate change as a result of the slowing down of atmospheric dynamics. The interconnection of energy-consuming regions and energy-rich (but remote) regions would prevent energy shortages in a world where fossil fuels are no longer used. The global grid (3), promoted by Prof. Damien Ernst, an engineer at the Montefiore Institute (School of Engineering) at ULiège, envisions the connection of regions which have a high potential for renewable energy resources and where local energy demand is low, with densely populated regions. The goal is to create a global network that would ensure the stability of the electricity supply system.y populated regions. A network that would ensure the stability of the electricity supply system.
Previous studies (2) in which researchers from the University of Liège participated have shown that Southern Greenland and Western Europe have complementary wind regimes. In particular, the southern tip of Greenland, which is attracting increasing interest for the development of wind farms, is one of the windiest places on the planet where the prevailing wind (called synoptic wind) due to the presence of the Icelandic low-pressure system is combined with a cold local wind (called katabatic wind) that permanently descends from the Greenland ice sheet (GrIS). It was therefore important to be able to measure the winds in this region in order to validate the climate model predicted by our researchers.
In 2020, the University of Liège set up the Katabata Project, a vast scientific project that aims to fill the gap in observation data in southern Greenland. Three self-contained and unmanned weather stations were installed in July 2020 by Michaël Fonder, an engineer at ULiège, in the areas where these powerful katabatic winds had previously been identified by climate modelling. “The katabatic winds are due to the presence of the polar cap," explains Clara Lambin, first author of the scientific article to be published in the International Journal of Climatology and researcher at the Laboratory of Climatology (SPHERES/Faculty of Science) at ULiège. “The surface air is cooled by its contact with the ice. As it cools, this air becomes denser and therefore heavier for the same volume as the surrounding air. It therefore flows by gravity along the slopes of the ice cap, forming the famous katabatic winds. Together with the prevailing winds, these winds can reach speeds of over 100 km/h.” In this preliminary study, it was established that between 1981 and 2100, the wind speed is expected to decrease by about -0.8 m/s at 100 m altitude in the South Greenland region. This decrease is particularly marked in winter, while in summer an acceleration of wind speed is expected along the margins of the ice sheet.
The data collected was used initially to validate the results of the MAR (Regional Atmospheric Model) climate model developed at ULiège. It turned out that this model represents reality fairly accurately and could therefore be used to create climate projections, a simulation of the future climate according to the emission scenarios envisaged by the IPCC, the Intergovernmental Panel on Climate Change. “In the projections created with MAR," explains Prof. Xavier Fettweis, a climatologist at ULiège, "the climate was simulated up to [the year] 2100 over Greenland with the atmosphere as it would be if we did not change our current level of consumption of fossil fuels, the IPCC's most pessimistic scenario. According to this projection, we can expect wind speeds to decrease over the southern tip of Greenland in winter, while they would remain rather stable in summer. This winter decrease can be explained by a phenomenon called 'Arctic amplification'. This is because the Arctic is warming four-times faster than on a global scale as a result of the gradual disappearance of the snow and ice cover (a light-reflective surface), giving way to darker surfaces that absorb more solar radiation. This much greater warming of the Arctic compared to the equator will reduce the thermal contrast between these two regions. This contrast, like air currents, is the real driving force behind our atmospheric dynamics, which will weaken in the coming decades, as we have already seen at our latitudes in recent years..." Fettweis also adds: "We can see that global warming will cause a much greater reduction in wind regimes in Europe!”
It also appears that the temporal variability of wind in the Arctic is complementary to European wind regimes. This means that in periods of low wind productivity, especially in summer when wind production is expected to decrease significantly, Europe could be supplied by Greenlandic wind farms in order to compensate for any shortfall in energy production with the implementation of the so-called Global Grid. The slight decrease in the prevailing (synoptic) wind speed in summer in Greenland will be compensated by the strengthening of the katabatic winds over the same period to give unchanged wind speeds in South Greenland in summer. Despite global warming, the air at the surface of the ice cap will always be kept at a maximum of 0°C by its contact with the ice. The warmer the surrounding air is compared to the surface air, the greater the difference in temperature, and therefore density, between the two masses and the faster the katabatic winds will flow down the slopes of the ice caps. As a result, the wind speed will stabilise in summer in southern Greenland, whereas it will decrease everywhere else.
This new study shows the potential benefits of connecting this windy region of South Greenland with Western Europe. The two regions have complementary wind regimes. This would mean that in the event of low wind production in Europe, an additional supply of electricity produced in Greenland would make up for the shortfall in local production and thus avoid having to compensate by using polluting fossil fuels. "To carry out such a project, it is necessary to study the technical and ecological issues further," concludes Prof. Ernst.
Scientific references
- Lambin C., Fettweis X., Kittel C., Fonder M. & Ernst D. Assessment of future wind speed and wind power changes over South Greenland using the MAR regional climate model, International Journal of Climatology, August 2022. https://orbi.be/handle/2268/288534
- Radu, D.-C., Berger, M., Fonteneau, R., Hardy, S., Fettweis, X., Le Du, M., Panciatici, P., Balea, L., & Ernst, D. (2019): Complementarity Assessment of South Greenland Katabatic Flows and West Europe Wind Regimes. Energy, 175, 393-40." https://orbi.uliege.be/handle/2268/230016
- Ersnt D., The Global Grid, 2013. https://orbi.be/handle/2268/173599
