W. M. Connolley and J. C. King
We have used data from 16 radiosonde stations to study the transport of water vapour in the Antarctic atmosphere. Total column moisture (TCM), winds and moisture flux measurements are presented, together with an analysis of their reliability. Annual TCM values are similar - about 4 kg m-2 - at all stations around the coast of East Antarctica. On the East Antarctic plateau, TCM values are much smaller. Over a period of 6 years, the interannual variation (standard deviation) of TCM is about 10% of the mean value.
At the coastal stations moisture fluxes reflect the predominantly zonal easterly flow in the lower troposphere and their meridional components are generally small. As a result of interannual variations in the strength of the atmospheric circulation, and to a lesser extent in the TCM, interannual variability of the fluxes is high, suggesting that there may be large interannual variability in the precipitation over Antarctica.
We have computed a water vapour budget for East Antarctica from our data. The annual accumulation rate obtained agrees surprisingly well with glaciological estimates. However, the uncertainties are considerable as a result of measurement errors and the representativity of the stations available. We conclude that our data are more suitable for evaluating the regional performance of circulation models from which systematic budget estimates may be derived.
The dataset used in this paper is now available on the web: /public/icd/data/wmc-radiosonde-export/.