Meteorological atmospheric boundary layer measurements and ECMWF analyses during summerat Dome C, Antarctica

摘要

Six levels of meteorological sensors have been deployed along a 45 m tower at the French-Italian Concordia station, Dome C, Antarctic. We present measurements ofvertical profiles, the diurnal cycle, and interdiurnal variability of temperature, humidity,and wind speed and direction for 3 weeks during the southern summer of 2008. Thesemeasurements are compared to 6-hourly European Center for Medium-Range Forecasts(ECMWF) analyses and daily radiosoundings. The ECMWF analyses show a 3-4°Cwarm bias relative to the tower observations. They reproduce the diurnal cycle oftemperature with slightly weaker amplitude and weaker vertical gradients. The amplitudeof the diurnal cycle of relative humidity is overestimated by ECMWF because theamplitude of the absolute humidity diurnal cycle is too small. The nighttime surface-basedwind shear and Ekman spiral is also not reproduced in the ECMWF analyses. Radiosondetemperatures are biased low relative to the tower observations in the lowest 30 m butapproach agreement at the top of the tower. Prior to bias correction for age-relatedcontamination, radiosonde relative humidities are biased low relative to the towerobservations in the lowest 10 m but agree with tower observations above this height. Aftercorrection for the age-related bias, the radiosonde relative humidity agrees with towerobservations below 10 m but is biased high above this height. Tower temperatureobservations may also be biased by solar heating, despite radiation shielding and naturalventilation.