Observations of near-surface wind and temperature structures and their variations with topography and latitude in East Antarctica

Abstract

The first multiyear surface meteorological observations over Dome A, the highest ice feature in the entire Antarctica continent, are analyzed to understand the surface wind, temperature, and stability climatology over Dome A and how it differs from the surface climatology at two lower-latitude/lower- elevation sites along similar longitude in East Antarctica. The climatology is also compared with that over Dome C. In contrast to the surface winds at lower sites, where moderate to strong northeasterly winds prevail with a distinct diurnal oscillation in wind speed in response to the diurnal change in katabatic forcing, summertime surface winds over Dome A are very weak, are variable in direction, and show little diurnal variation. Although both temperature and temperature gradient oscillate diurnally, the gradient over Dome A remained positive all day long, indicating a persistent surface inversion, while at the two lower sites, as well as over Dome C, sufficient insolation leads to the breakup of inversion and the development of a convective boundary layer in the afternoon. Wavelet analysis of near-surface stability revealed that besides the strong diurnal signal, the near-surface stability also exhibits annual, semiannual, and interseasonal (period ∼50 days) oscillations at all locations. These oscillations in near-surface stability are linked to the same peaks in the 500-hPa geopotential height spectra and therefore are believed to be caused by variations of synoptic conditions. Copyright 2009 by the American Geophysical Union.