Genesis of diamond dust, ice fog and thick cloud episodes observed and modelled above Dome C, Antarctica

Year: 2017

Authors: Ricaud P., Bazile E., Del Guasta M., Lanconelli C., Grigioni P., Mahjoub A.

Autors Affiliation: Météo-France/CNRM, CNRS UMR 3589, 42 avenue Gaspard Coriolis, Toulouse, 31057, France; INO-CNR, Via Madonna del Piano 10, Sesto Fiorentino, 50019, Italy; Institute of Atmospheric Sciences and Climate (ISAC), Consiglio Nazionale Delle Ricerche, Via Gobetti 101, Bologna, 40129, Italy; ENEA, Lungotevere Thaon di Revel, Rome, 76-00196, Italy; Joint Research Center, Institute for Environment and Sustainability (IES), Land Resource Management Unit (H05), Via Fermi, Ispra (VA), 21027, Italy

Abstract: Episodes of thick cloud and diamond dust/ice fog were observed during 15 March to 8 April 2011 and 4 to 5 March 2013 in the atmosphere above Dome C (Concordia station, Antarctica; 75°06′ S, 123°21′ E; 3233 m a.m.s.l.). The objectives of the paper are mainly to investigate the processes that cause these episodes based on observations and to verify whether operational models can evaluate them. The measurements were obtained from the following instruments: (1) a ground-based microwave radiometer (HAMSTRAD, H2O Antarctica Microwave Stratospheric and Tropospheric Radiometers) installed at Dome C that provided vertical profiles of tropospheric temperature and absolute humidity every 7 min; (2) daily radiosoundings launched at 12:00 UTC at Dome C; (3) a tropospheric aerosol lidar that provides aerosol depolarization ratio along the vertical at Dome C; (4) down-and upward short-and long-wave radiations as provided by the Baseline Surface Radiation Network (BSRN) facilities; (5) an ICE-CAMERA to detect at an hourly rate the size of the ice crystal grains deposited at the surface of the camera; and (6) space-borne aerosol depolarization ratio from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) lidar aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) platform along orbits close to the Dome C station. The time evolution of the atmosphere has also been evaluated by considering the outputs from the mesoscale AROME and the global-scale ARPEGE meteorological models. Thick clouds are detected during the warm and wet periods (24-26 March 2011 and 4 March 2013) with high depolarization ratios (greater than 30 %) from the surface to 5-7 km above the ground associated with precipitation of ice particles and the presence of a supercooled liquid water (depolarization less than 10 %) clouds. Diamond dust and/or ice fog are detected during the cold and dry periods (5 April 2011 and 5 March 2013) with high depolarization ratios (greater than 30 %) in the planetary boundary layer to a maximum altitude of 100-300 m above the ground with little trace of precipitation. Considering 5-day back trajectories, we show that the thick cloud episodes are attributed to air masses with an oceanic origin whilst the diamond dust/ice fog episodes are attributed to air masses with continental origins. Although operational models can reproduce thick cloud episodes in the free troposphere, they cannot evaluate the diamond dust/ice fog episodes in the planetary boundary layer because they require to use more sophisticated cloud and aerosol microphysics schemes.

Journal/Review: ATMOSPHERIC CHEMISTRY AND PHYSICS (PRINT)

Volume: 17 (8)      Pages from: 5221  to: 5237

More Information: The present research project HAMSTRAD programme (910) has been performed at the Dome C station and was supported by the French Polar Institute, Institut polaire francais Paul-Emile Victor (IPEV), the Institut National des Sciences de l´Univers (INSU)/Centre National de la Recherche Scientifique (CNRS), Meteo-France and the Centre National d´Etudes Spatiales (CNES). The permanently manned Concordia station is jointly operated by IPEV and the Italian Programma Nazionale di Ricerche in Antartide (PNRA). We would like to thank all the winter-over personnel who worked at Dome C on the different projects: HAMSTRAD, Routine Meteorological Observations (RMO), aerosol lidar and BSRN. Thanks to the British Atmospheric Data Centre, which is part of the Natural Environment Research Council (NERC) National Centre for Atmospheric Science (NCAS), for the calculation of trajectories and access to European Centre for Medium-Range Weather Forecasts (ECMWF) data. We have used NCEP Reanalysis data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their website at http://www.esrl.noaa.gov/psd/. The authors also would like to thank the CALIPSO science team for providing the CALIOP images at http://www-calipso.larc.nasa.gov/. HAMSTRAD data are available at http://www.cnrm.meteo.fr/spip.php?article961&lang=en. RMO data are available at http://www.climantartide.it. We finally would like to thank the three anonymous reviewers for their fruitful.
KeyWords: aerosol; boundary layer; dust; fog; ground-based measurement; longwave radiation; microwave radiometer; polar region; shortwave radiation; troposphere; vertical profile, Antarctica; Dome Concordia; East Antarctica
DOI: 10.5194/acp-17-5221-2017

Citations: 17
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