Coastal polynyas are primarily wind driven openings in the sea ice close to shore. They are important drivers of sea ice production, ocean circulation and have important consequences for polar ecology. Accurate understanding and modelling of the Earth system in the polar regions requires a thorough representation of polar climate processes including polynyas and sea ice. This paper investigates the evolution of coastal polynyas and their atmospheric impacts in Greenland and Antarctica by analysing two satellite products alongside simulations from a regional climate model (RCM). We examine how the representation of polynyas differs between the satellite datasets and how these differences affect the RCM when used as boundary conditions. We further explore how the modelled polynyas influence surface atmospheric conditions, boundary layer and cloud properties. Our analysis is based on the Harmonie-Climate (HCLIM) regional climate model, which employs spectral nudging and a surface scheme optimised for polar regions. The model provides a flexible framework for process studies, including with direct use of Earth Observation data such as a new higher spatial resolution satellite product, developed by the ESA climate change initiative (CCI) for sea ice. We run the model over both polar regions, to examine the impact of coastal polynyas in northern Greenland in 2018 and Terra Nova Bay in Antarctica in 2010. Comparison between runs shows an improved representation of climate with the high resolution sea ice product, particularly in boundary layer properties and near the coast which standard resolution sea ice data often has difficulty capturing. Our results show that using the high resolution CCI sea ice data directly in regional climate models can improve characterisation of near-surface weather and climate, supplementing the use of fully coupled atmosphere -ocean- sea ice modelling for process understanding and argue for the inclusion of this data in assimilation systems used for reanalysis.