Long term wind speed and wind power change analysis over South Greenland using the regional climate model MAR.

Fighting global warming implies replacing fossil fuels by renewable energy sources. Wind has the benefit to be an easily accessible and infinitely renewable resource but is not evenly distributed in space and time. A solution to prevent energy scarcity in a decarbonised world would be the building of a global interconnected grid that provide populated regions with electricity generated in remote but resourceful areas. In this context, it has appeared in previous studies that Greenland and Europe have complementary wind regimes. In particular, the southern tip of Greenland, Cape Farewell, has gained increasing interest for wind farm development as it is one of the windiest places on Earth. In order to gain new insights about future wind speed variations over South Greenland, the Modèle Atmosphérique Régional (MAR), validated against in situ observations over the ice-free area where wind turbines are most likely to be installed, is used to built climate projections under the emission scenario SSP 5-8.5 by downscaling an ensemble of CMIP6 earth system models (ESMs). These projections enable to assess the long term wind speed and maximum wind power change between 1981 and 2100 over Cape Farewell, quantified with the help of a linear regression. It appears from this analysis that, during this period over the ice-free area, the annual wind speed is expected to decrease of ~-0.8 m/s at 100m a.g.l. This decrease is particularly marked in winter while in summer, wind speed acceleration occurs along the ice sheet margins. An analysis of two-dimensional wind speed change at different vertical levels indicates that this decrease is likely due to synoptic circulation change, while in summer, the katabatic winds gowing down the ice sheet are expected to increase due to an enhaced temperature contrast between the ice sheet and the surroundings. As for the mean annual maximum wind power a turbine can yield, a decrease of ~-300.5 W is to be expected over the ice-free area of Cape Farewell between 1981 and 2100 at 100m a.g.l. Again, the decrease is especially marked in winter. Considering the very high winter wind speeds occuring in South Greenland which can cut off wind turbines if too intense, the projected wind speed decrease might be beneficial for the establishment of wind farms near Cape Farewell.