During the Arctic Ocean 2001 expedition we took continuous turbulence and profile measurements during 3 weeks on an 18-m mast erected on a 1.5 by 3 km large ice floe near the North Pole, at 89°N.

The boundary layer during the entire period was relatively well mixed and very moist - the relative humidity was above 90% more than 80% of the time and the visibility was below 10 km more than half the time. In this presentation we discuss the fluxes of momentum, heat, water and aerosols and relate these to the mean profiles. The results are put in to the context of boundary layer dynamics using boundary layer soundings and the Sodar echo-structure. The study is focussed on a period of two days, when there was a very pronounced capping inversion, with maximum temperatures at 1 km ~ 10 °C warmer than at the surface.