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

[1] 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 of vertical profiles, the diurnal cycle, and interdiurnal variability of temperature, humidity, and wind speed and direction for 3 weeks during the southern summer of 2008. These measurements are compared to 6-hourly European Center for Medium-Range Forecasts (ECMWF) analyses and daily radiosoundings. The ECMWF analyses show a 3–4°C warm bias relative to the tower observations. They reproduce the diurnal cycle of temperature with slightly weaker amplitude and weaker vertical gradients. The amplitude of the diurnal cycle of relative humidity is overestimated by ECMWF because the amplitude of the absolute humidity diurnal cycle is too small. The nighttime surface-based wind shear and Ekman spiral is also not reproduced in the ECMWF analyses. Radiosonde temperatures are biased low relative to the tower observations in the lowest 30 m but approach agreement at the top of the tower. Prior to bias correction for age-related contamination, radiosonde relative humidities are biased low relative to the tower observations in the lowest 10 m but agree with tower observations above this height. After correction for the age-related bias, the radiosonde relative humidity agrees with tower observations below 10 m but is biased high above this height. Tower temperature observations may also be biased by solar heating, despite radiation shielding and natural ventilation.

[1]  David H. Bromwich,et al.  Polar Radiation Budgets of the NCAR CCM3 , 1998 .

[2]  Von P. Walden,et al.  Radiosonde Temperature Measurements in Strong Inversions: Correction for Thermal Lag Based on an Experiment at the South Pole , 1997 .

[3]  D. Bailey,et al.  Development of an Antarctic Regional Climate System Model. Part II: Station Validation and Surface Energy Balance , 2000 .

[4]  D. As,et al.  Structure and dynamics of the summertime atmospheric boundary layer over the Antarctic Plateau: 2. Heat, moisture, and momentum budgets , 2006 .

[5]  Eric Aristidi,et al.  On the atmosphere for astronomers above Dome C, Antarctica , 2006, Antarctic Science.

[6]  D. As,et al.  Daily cycle of the surface layer and energy balance on the high Antarctic Plateau , 2005, Antarctic Science.

[7]  T. Travouillon,et al.  Atmospheric turbulence at the South Pole and its implications for astronomy , 2003 .

[8]  J. King,et al.  Heat and water vapour fluxes and scalar roughness lengths over an Antarctic ice shelf , 1994 .

[9]  Chad W. Higgins,et al.  Albedo effect on radiative errors in air temperature measurements , 2009 .

[10]  S. Argentini,et al.  Contrasts between the summertime surface energy balance and boundary layer structure at Dome C and Halley stations, Antarctica , 2006 .

[11]  J. King.  Some measurements of turbulence over an antarctic ice shelf , 1990 .

[12]  S. Warren,et al.  Reflection of solar radiation by the Antarctic snow surface at ultraviolet, visible, and near‐infrared wavelengths , 1994 .

[13]  Philip S. Anderson,et al.  MECHANISM FOR THE BEHAVIOR OF HYDROACTIVE MATERIALS USED IN HUMIDITY SENSORS , 1995 .

[14]  John W. V. Storey,et al.  First Measurements of the Infrared Sky Brightness at Dome C, Antarctica , 2005 .

[15]  S. Warren,et al.  Temperature, Humidity, and Pressure Response of Radiosondes at Low Temperatures , 2004 .

[16]  W. Schwerdtfeger,et al.  Weather and climate of the Antarctic , 1984 .

[17]  David Carlson,et al.  Corrections of Humidity Measurement Errors from the Vaisala RS80 Radiosonde—Application to TOGA COARE Data , 2002 .

[18]  C. Genthon,et al.  ECMWF Analyses and Predictions of the Surface Climate of Greenland and Antarctica. , 1995 .

[19]  J. Turner,et al.  Significant Warming of the Antarctic Winter Troposphere , 2006, Science.

[20]  David N. Whiteman,et al.  Accuracy assessment and correction of Vaisala RS92 radiosonde water vapor measurements , 2009 .

[21]  Validation of operational numerical analyses in Antarctic latitudes , 1997 .

[22]  D. Bromwich,et al.  Surface Energy Balance of the NCEP MRF and NCEP–NCAR Reanalysis in Antarctic Latitudes during FROST , 1999 .

[23]  V. Walden,et al.  Surface energy budget over the South Pole and turbulent heat fluxes as a function of an empirical bulk Richardson number , 2009 .

[24]  G. Kaser,et al.  Ventilated and unventilated air temperature measurements for glacier‐climate studies on a tropical high mountain site , 2002 .

[25]  Philip J. Rasch,et al.  Antarctic Clouds and Radiation within the NCAR Climate Models , 2004 .

[26]  David N. Whiteman,et al.  Absolute accuracy of water vapor measurements from six operational radiosonde types launched during AWEX-G and implications for AIRS validation , 2006 .

[27]  I. Petenko,et al.  Summer boundary-layer height at the plateau site of Dome’C, antarctica , 2005 .

[28]  M. Legrand,et al.  Year-round record of size-segregated aerosol composition in central Antarctica (Concordia station): Implications for the degree of fractionation of sea-salt particles , 2008 .

[29]  John C. King,et al.  Validation of the surface energy balance over the Antarctic ice sheets in the U.K. Meteorological Office unified climate model , 1997 .

[30]  John W. V. Storey,et al.  An analysis of temperatures and wind speeds above Dome C, Antarctica , 2005 .

[31]  S. Hudson,et al.  A Look at the Surface-Based Temperature Inversion on the Antarctic Plateau , 2005 .

[32]  John C. King,et al.  Evaluation of Turbulent Surface Flux Parameterizations for the Stable Surface Layer over Halley, Antarctica* , 2001 .

[33]  David D. Turner,et al.  Dry Bias in Vaisala RS90 Radiosonde Humidity Profiles over Antarctica , 2008 .

[34]  Shepard A. Clough,et al.  Improved Daytime Column-Integrated Precipitable Water Vapor from Vaisala Radiosonde Humidity Sensors , 2008 .