The influence of coastal morphology on wind dynamics

An analysis of the dynamics of wind velocity along the Baltic coast of Lithuania is presented, based on data collected during field experiments in the summer, fall and winter of 1999-2001 and 2007-2009 at several sites (Butinge, Saipiai, Smiltyne, Juodkrante, Pervalka and Nida). The locations were chosen in order to encompass a wide spectrum of beach and dune ridge morphology. The relationship between wind velocity dynamics and coastal morphology was established, based on measurements of the slope angle, height and shape of the dune crest, as well as measurements of the morphology of the area behind the foredune ridge. On the basis of a comparison of near-surface wind velocity patterns, shear velocity (U*) and surface roughness length (z(0)) were calculated. It was determined that U* decreases from the middle of the beach towards the foredune toe, then increases towards the crest of the foredune and decreases down the lee slope. A direct correlation exists between U* and the stoss slope inclination, and the relative height of the foredune. Surface roughness length also increases from the beach towards the foredune crest.