Modelling flow in the porous bottom of the Barents Sea shelf

Abstract

In their recent paper, Węsławski et al. (2012) showed that the Svalbardbanken area of the Barents Sea is characterized by a high organic carbon settlement to the permeable sea bed, which consists of gravel and shell fragments of glacial origin. In the present paper, which can be considered as a supplement to the Węsławski et al. paper, two potential hydrodynamic mechanisms of downward pore water transport into porous media are discussed in detail. In particular, estimated statistical characteristics of the pore water flow, induced by storm surface waves, indicate that the discharge of water flow can be substantial, even at large water depths. During stormy weather (wind velocity V=15ms−1 and wind fetch X=200km) as much as 117.2 and 26.1m3hour−1 of water filter through the upper 5m of the shell pit at water depths of 30 and 50m respectively. For a porous layer of greater thickness, the mean flow discharge is even bigger.The second possible mechanism of flow penetration in the porous layer is based on the concept of geostrophic flow and spiral formation within the Ekman layer. Assuming that the current velocity in the near-bottom water layer is u¯=1m, the resulting mean discharge through this layer becomes as large as 0.99 and 0.09m3s−1 for downstream and transverse flows respectively.