CLIMB is coordinated by the Royal Meteorological Institute of Belgium with partners Ghent University (research group EnVOC, Prof. Walgraeve), Katholieke Universiteit Leuven (KUL Department of Earth and Environmental Sciences, Prof. Nicole van Lipzig), and the Royal Belgian Institute for Space Aeronomy (IASB-BIRA, Dr. Michel Van Roozendael, UV-Vis DOAS Research). The Leibniz Institute for tropospheric research, TROPOS, in Leipzig, Germany, is a sub-contracted partner. CLIMB is financed by the Belgian Science Policy Office (BELSPO) BRAIN-be programme.

The water cycle, cloud microphysics and cloud-aerosol-interactions are recognized as key elements of the Antarctic climate system. Clouds and aerosols play a significant role in the radiative energy budget and aerosols impact cloud microphysics because they are cloud condensation and ice nuclei. In addition, clouds are an important part of the hydrological cycle serving as the agent linking water vapour transport into Antarctica with precipitation. Because precipitation is the only source term in the surface mass balance (SMB) of the Antarctic ice sheet, it is one of the key factors affecting sea level. However, current knowledge on the interaction between clouds, precipitation and aerosol in the Antarctic is still limited, both from direct observations and from regional climate models.

At the Belgian Antarctic research station Princess Elisabeth (PES), an observatory for aerosol, cloud and precipitation properties exists. The synergy of the data sets has been exploited in first case studies on the effect of aerosols on cloud and precipitation processes with an improved aerosol-cloud-precipitation parameterisation of the regional climate model (RCM) COSMO-CLM². First results show a strong sensitivity of cloud microphysics to the number of ice nucleating particles (INP), and to a less degree to the number of cloud condensation nuclei (CCN). CLIMB proposes to do systematic measurements of INP at PES, combined with meteorological, aerosol and cloud microphysics observations – both made at PES and at the typical precipitating cloud level and improving the aerosol-cloud-precipitation parameterisation in a regional climate model for East Antarctica.

General objectives and underlying research questions:

The objectives of CLIMB are:

• CLIMB will deliver a unique data set of in-cloud meteorological, aerosol and cloud characteristics, combined with simultaneous boundary layer and ground-based remote sensing measurements;
• The CLIMB data set will enable a detailed mapping of air mass origins and thus the transport mechanisms into East Antarctica, relevant for the surface mass balance ;
• CLIMB will generate an improved COSMO-CLM² regional climate model (member of POLAR-CORDEX) for Antarctica;
• CLIMB will improve the understanding of the climatological effect of INP and on clouds, precipitation, radiation and the surface mass balance in East Antarctica;

Main research questions are:

• What are the meteorological, aerosol and cloud characteristics at different altitude levels near PES?
• Which volatile organic compounds (VOCs) are present at cloud-level?
• What are the air mass origins?
• What is the abundance of INP near PES?
• What are the results of the improved parameterisation for the surface mass balance?

Methodology

The CLIMB project will comprise to do measurements of meteorological, aerosol, cloud and precipitation characteristics directly at the cloud level, at a mountain top, with small-sized instrumentation, including:  

• A vertically resolved, continuous (year-round) profile of temperature, relative humidity and pressure for three heights: at PES (1390 m asl), on the Utsteinen nunatak summit (around 1600 m asl) and in the Vikinghogda mountains (around 2600 m asl).
• Measurements of precipitation type, intensity and droplet/crystal size by a disdrometer. One will be placed in the mountain and one at PES.
• In-cloud measurements of aerosol particle number size distribution;
• An automated sampling system for VOCs; year-round sampling might be possible.

In addition, at PES (1390 m asl) there will be:

• The operational aerosol-cloud-precipitation observatory (see www.aerocloud.be);
• INP filter sampling;
• Active sampling of airborne particles for organic chemistry and for VOCs

1 December 2020 - April 2022.

Project PI at RMI: Dr. Alexander Mangold

Contact:
Royal Meteorological Institute of Belgium
Ringlaan 3, Avenue Circulaire
BE-1180 Brussels, Belgium
Tel: 0032-23730593