A study of the structure of low-level katabatic winds at Mizuho Station,East Antarctica

Low-level katabatic wind profiles, which have shapes similar to those of the low-level jet (LLJ) wind profiles, are often observed during strong winds in the summer period at Mizuho Station, which is located at 70°42 S, 44°20 E in East Antarctica. The profiles may be classified according to the height of the maximum wind speed, z_m, found below 30 m height. The behavior of zm and of conditions in the layer above zmare explained well by the normalized frequency, fN = Nz/U at 30 m, whose value can be used to predict the existence of a LLJ wind profile. Subsidence and inertial oscillations above zm are related closely to the height and time variations of zm. Thus, not only effects emanating upward from surface but also momentum and heat transported downward from above are significant for the evolution of zm.