Momentum and Sensible Heat Exchange in an Ice-Free Arctic Fjord

Abstract

Momentum and sensible heat exchange are studied in an Arctic fjord system in Spitsbergen, Svalbard (Norway), based on tower measurements taken in January–June 2008. Due to ice-free conditions, the surface layer was unstable for most of the time, occasionally very unstable. The shape of the fjord and the surrounding topography have a large influence on the wind field. Low frequency eddies are mainly responsible for occasionally large crosswind momentum transfer that, together with upward momentum transfer (occurring in 9% of the data), invalidate conventional stability and scaling parameters. When the flow is along the fjord with moderate or high wind speeds, the Monin–Obukhov similarity theory is applicable. However, the momentum and the sensible heat exchange in the fjord system differs from the exchange taking place over the open ocean, mainly due to topographic effects.