Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 6 4 2006 10.5194/acpd-6-7697-2006 http://www.atmos-chem-phys-discuss.net/6/7697/2006/ http://www.atmos-chem-phys-discuss.net/6/7697/2006/acpd-6-7697-2006.html http://www.atmos-chem-phys-discuss.net/6/7697/2006/acpd-6-7697-2006.pdf 7697 7714 2006-08-09 Mid-winter lower stratosphere temperatures in the Antarctic vortex: comparison between observations and ECMWF operational model. M. C. Parrondo M. Yela M. Gil P. von der Gathen H. Ochoa Instituto Nacional de Técnica Aeroespacial, Torrejón de Ardoz, Spain Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Germany Dirección Nacional de Antártico, Buenos Aires, Argentina Radiosonde temperature profiles from Belgrano (78° S) and other Antarctic stations have been compared with European Centre for Medium-Range Weather Forecasts (ECMWF) data during the winter of 2003. Results show a bias in the operational model which is height and temperature dependent, being too cold at layers peaking at 80 and 25–30 hPa, and hence resulting in an overestimation of the predicted potential PSC areas. Here we show the results of the comparison by considering the possibility of a bias in the sondes at extremely low temperatures and discuss the potential implications that this bias might have on the ozone depletion computed by Climate Transport Model based on ECMWF temperature fields.