Diurnal variation of the planetary boundary layer over Dome C (Antarctica) impacting the formation of supercooled liquid water clouds

Year: 2025

Authors: Ricaud P., Durand P., Grigioni P., Ciardini V., Del Guasta M., Camporeale G., Attiy J.L., Bazile E.

Autors Affiliation: Univ Toulouse, CNRM, Meteofrance, CNRS, Toulouse, France; Univ Toulouse, Lab Aerol, CNRS, Toulouse, France; ENEA, Rome, Italy; CNR, INO, Sesto Fiorentino, FI, Italy; CNR, IREA, Bari, Italy.

Abstract: While the majority of Antarctic clouds are made up of ice crystals, a significant proportion consists of supercooled liquid water (SLW), defined as water in liquid form below 0 degrees C. Observations of SLW clouds have been carried out for several years at Dome C, the Concordia station (75 degrees S, 123 degrees E; 3233 m above mean sea level), combining observations from LIDAR, microwave radiometer and balloon-borne sondes. The present analysis is separated in two parts. Firstly, we will focus on the diurnal variation of the planetary boundary layer (PBL) from balloon-borne profile observations performed on January 23, 2023 establishing the presence of SLW clouds: 1) at the top of the PBL between the entrainment zone and the capping inversion layer, 2) higher up within a fossil layer, and 3) within the very cold stable boundary layer close to the surface as liquid fog. Secondly, from a statistical study covering several summer periods, we will show that SLW clouds are present from 400 to 600 m above ground level (agl) in the entrainment zone and within the stable boundary layer below 100 m agl where liquid fog can form, with temperatures from-25 degrees C to-35 degrees C and LWP (liquid water path, the vertically-integrated SLW content) less than 3.0 g m-2.

Journal/Review: POLAR SCIENCE

Volume: 46      Pages from: 101256-1  to: 101256-16

More Information: The HAMSTRAD programme (910) and the SLW-CLOUDS programme (1247) were supported by the French Polar Institute (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 staffed Concordia station is jointly operated by IPEV and the Italian Programma Nazionale Ricerche in Antartide (P NRA). The tropospheric LIDAR operates at Dome C from 2008 within the framework of several Italian national (PNRA) projects. Meteorological radiosonde launches and the ceilometer are operated within the framework of the Italian Antarctic Meteorological Observatory (IAMCO) of the PNRA. We would like to thank all the winter over personnel who worked at Dome C on the different projects: HAMSTRAD, aerosol LIDAR, and IAMCO for operational meteorological soundings and in situ balloon-borne observations. Finally, we would like to thank the two anonymous reviewers for their beneficial comments.
KeyWords: Antarctica; Argentina; Concordia; Dome Concordia; Entre Rios; boundary layer; cloud cover; diurnal variation; lidar; microwave radiometer
DOI: 10.1016/j.polar.2025.101256