The Ronne Polynya is a coastal polynya, which is an area of open water in pack ice caused by the offshore advection of the ice by strong continental winds as quickly as it can form. The atmosphere above and downwind of the polynya is warmed by the open water, leading to the formation of a convective internal boundary layer (CIBL). Quantification of the ocean-atmosphere heat fluxes is a step towards quantifying the surface energy budget, which will aid understanding of the key processes governing deep water formation in this region. High frequency wind and temperature data from three surface layer flights over the Ronne Polynya were collected on separate dates in February 2007 from the British Antarctic Survey's newly instrumented twin otter aircraft. The evolution with offshore distance of sensible and latent heat fluxes and CIBL structure have been calculated for these cases. Relationships between surface ice thickness and the neutral drag coefficient (CDN) and exchange coefficient for sensible heat flux (CHN) have also been investigated. The data have been used to validate and improve the output of heat fluxes and boundary layer height from a simple fetch-dependent CIBL model.