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The Arctic is undergoing big changes, there has been a reduction in sea ice extent and an increase in the amount of thinner, newer ice. This changing surface causes challenges to numerical weather prediction and climate simulation, due to the very interconnected nature of the surface and atmosphere in the Arctic. Changes to the surface may impact on the air temperature, the surface fluxes of heat and moisture and the microphysics of clouds amongst others. These areas could also, in turn, change the surface. The Marginal Ice Zone (MIZ) is the area of the sea ice which is between the open water and solid ice, and is characterised by a complex and constantly changing ice surface. The impact of thinning ice in the MIZ was investigated using a series of idealised modelling experiments, and it was found that thinner sea ice in the MIZ would increase the surface temperature and fluxes of heat. In turn this causes the clouds, which formover the open water, to formcloser to the ice edge. The clouds were found to be thinner for the experiments with thinner ice, which resulted in them allowing more shortwave radiation to reach the surface. This result implies that thinning sea ice would act to further thin sea ice. Using observations from the Aerosol- Clouds Coupling And Climate Interactions in the Arctic (ACCACIA) campaign, two sets of model sensitivity studies were undertaken to test which boundary layer parametrisation schemes would performbetter. It was discovered that the boundary layer in the model is more sensitive to the surface representation rather than the choice of boundary layer scheme. These results point to the need for more work, both observations and modelling, on the sea ice and its impact on the atmosphere in order to better predict the changes the Arctic and the planet will undergo with a changing climate.