THERMALLY AND FRICTIONALLY PRODUCED WIND SHEAR IN THE PLANETARY BOUNDARY LAYER AT LITTLE AMERICA, ANTARCTICA

Abstract

Pilot balloon wind profiles obtained by the first and second Byrd Antarctic Expeditions are analyzed to show that the mean observed wind shear between the surface and 1,000 m. can be resolved into a frictional component which produces a normal boundary layer wind spiral, and a thermal component resulting from the temperature gradient at the ice edge, which deforms the normal wind spiral. Values of surface stress, surface Rossby number, geostrophic drag coefficient, energy dissipation, and roughness length derived from the wind profiles are collectively sufficiently different from values obtained over land or water surfaces, to suggest that the ice surface produces its own characteristic wind distribution.