Sahara Dust over Barbados
The big cloud systems over the tropics are especially interesting from a climatological perspective. That is why the Max Planck Institute for Meteorology in Hamburg has embarked on a two-year field campaign in Barbados with a group led by Bjorn Stevens. Their aim is to study the interplay between aerosols, clouds, precipitation and the climate. They are accompanied by the two teams from Mainz headed by Meinrat Andreae and Stephan Borrmann.
Barbados is particularly interesting as it is among the easternmost islands in the Caribbean. When the trade winds blow across the Atlantic from the east in the early summer, they carry almost exclusively natural aerosols with them – above all Sahara dust. At other times of the year, the winds blow in different directions. Then they may carry with them, for instance, soot released by humans burning biomass. Under these circumstances, scientists can use the large-scale weather patterns that vary with the seasons to study how clouds and precipitation behave in their undisturbed state and how mankind influences them.
The measuring instruments have been set up on two peninsulas at the far east of Barbados so that anthropogenic influence is virtually excluded when the weather patterns come from an easterly direction. The remote sensing equipment includes laser systems that screen the atmosphere for water vapor content and aerosols. There is also a cloud radar.
In addition, the HALO research aircraft, operated by the German Aerospace Center (DLR) and partly financed by the Max Planck Society, will fly over Barbados taking measurements. “Spies in the sky” complement the program: the so-called A-Train consisting of six NASA research satellites crosses the skies above Barbados as well. Climate scientists are hopeful that the elaborate system of measurements will deliver precise knowledge about aerosols, clouds and precipitation in the important equatorial region. This should then allow the simulation of more precise computer models of climate development.
