Arctic Sun Show

Photometer Calibration on Spitsbergen
For two weeks, starting on March 23, twelve sun photometers will be facing the allegedly clear Arctic sky. The concerted data-recording operation represents essential groundwork towards the assessment of air pollution planned for the International Polar Year 2007/2008. At that time, the programme, operating with previously unknown accuracy, will measure aerosols to determine pollution levels at more than twenty locations throughout the polar regions. Twenty scientists from nine nations are gathering at the French German AWIPEV Research Base on Spitsbergen to calibrate their spectral radiometers. The research base is operated jointly by the Alfred Wegener Institute and the French polar research institute Paul Emile Victor.

Under the cooperative leadership of the Alfred Wegener Institute for Polar and Marine Research and the Italian Institute for Atmospheric Research Bologna, 9 of the 19 nations united in the POLAR-AOD network (Aerosol Optical Depth in Polar Regions), are meeting in Ny-Ålesund on Spitsbergen. Sun photometers represent special modification of radiometers, designed to measure sun intensity in various colour ranges. By comparing light intensities at ground level and outside the atmosphere, the amount of light retained in the air through scatter and absorption can be determined. Changes in intensity coincide with colour changes of sunlight. In addition, the colour changes provide information about the qualities of aerosols, i.e. fine dust particles reducing light penetration in the atmosphere.

Sea salt, Sahara dust and exhaust fumes
Atmospheric aerosols have a significant effect on radiation balance, and consequently on the Earth’s climate. Naturally occurring aerosols include droplets of sulphuric acid, sea salt, Sahara dust as well as other mineral components. However, the human influence has been increasing. “Nowadays, twenty to thirty percent of atmospheric aerosols are produced by humans through incinerations, air traffic and industrial exhaust fumes”, says Dr Andreas Herber of the Alfred Wegener Institute, organiser of the calibration of instruments on Spitsbergen.

The Earth’s polar regions are key areas for our climate. A detailed understanding and a comprehensive description of the aerosol pollution are important prerequisites for precise climate predictions. One objective of the POLAR-AOD network is to understand the pathways by which anthropogenic, but also natural, aerosols are transported to the polar regions. For the first time ever, the temporal and spatial coverage of study areas will allow a global assessment of optical aerosol effects, including at both poles.

More Informations about the Polar-AOD project on the Web

Bremerhaven, March 23, 2006