Mesoscale meteorological conditions in Dronning Maud Land, Antarctica, during summer: the momentum budget of the boundary layer

Abstract

The momentum budget of the boundary layer flew near the Swedish research station Svea in the mountainous region of western Dronning Maud Land, Antarctica, is evaluated using detailed concurrent observations of surface meteorological variables, high-resolution boundary layer profiles and upper-air profiles taken during the summer of 1997–98. Despite the fact that the irregular topographical situation prohibits easy interpretation of the data, interesting features can still be identified. All terms in the momentum budget (katabatic forcing, synoptic pressure gradient, Coriolis force and friction) can be of the same order of magnitude, which indicates that the influence of each term depends largely on the prevailing conditions. More precisely, the relative importance of the various momentum terms varies strongly with altitude, location, time of day and prevailing synoptic conditions. For example, at the undisturbed snow slopes there is a very regular daily variation of katabatically forced flow during the night and a flow dominated by the synoptic pressure gradient during the day, causing a persistent diurnal cycle in surface wind direction. The interpretation of the flow characteristics in terms of the momentum budget agrees favourably with the conclusions drawn on the basis of a general description of the prevailing meteorological conditions, and can therefore be considered consistent.