The influence of a single pressure ridge of 4.5 m height on thestructure of the atmospheric surface layer is studied.The field of the mean wind velocity is governed by typical featuresof a Bernoulli effect with a speedup over the crestand a shadowing effect downwind of the ridge.It is found that the turbulence generated bythe ridge compensates for thedeformation of the flow field by mixing momentum downward.Both mean and turbulent fields are restoredto their upwind values at a distance of appr. 300mdownwind of the ridge, which is equivalent to anaspect ratio of 0.015.The level of maximum turbulence generated by the ridgeis characterized by a linear relationship.A formulation for the determination of the form drag of asingle ridge is proposed and generalized towardan ensemble of ridges.We estimate that the form drag contributes< 50 % to the total drag exerted by a typicallyice covered sea surface on the atmospheric flow.
AWI Organizations > Climate Sciences > Physical Oceanography of the Polar Seas
AWI Organizations > Climate Sciences > Climate Dynamics
AWI Organizations > Climate Sciences > Sea Ice Physics