In recent decades the Arctic has undergone dramatic changes affecting sea ice, snow, permafrost, surface temperature, land, snow and atmospheric circulation. Temperatures are rising at a much higher pace compared to the rest of the world, which is commonly known as Arctic Amplification. A possible explanation of Arctic Amplification is the interplay between different processes fostering feedback mechanisms that further amplify changes in the environment.
These changes also affect transport pathways for aerosol and pollution into the Arctic due to the change in circulation patterns. Recent studies also pointed out the importance of air pollutants, e.g. black carbon and sulfate, for the enhanced warming trend in the Arctic region compared to lower latitudes. Especially in winter and spring, transport of pollutants form Eurasia leads to higher concentrations in the remote Arctic environment. On the other hand, the changing sea ice conditions due to the recent warming trend in the Arctic lead to an increased fraction of biogenic particles during summer which may also affect the radiative budget due to their influence on aerosol cloud interaction.
To date it is well known that transport into the Arctic and especially into the lower troposphere of the high Arctic is possible along different pathways depending on the source area of air masses and the time of the year. At the same time The high Arctic lower troposphere in general is quite well isolated from the rest of the Arctic by a transport barrier referred to as the Polar Dome. The Polar Dome is formed by sloping isentropes, the isolines of potential temperature Θ, as a result of radiative cooling in the high Arctic especially during the winter month without sunlight. However, triggered by synoptic scale disturbances the transport barrier can get permeable thus allowing mid-latitude air masses to enter the high Arctic lower troposphere that can in turn affect local air quality and Arctic climate in general.
Airborne in-situ trace gas data, aerosol data as well as numerical models and lagrangian analysis methods are used in the AG Hoor to better understand and constrain transport regimes, the Polar Dome as well as aerosol-cloud interactions in the Arctic.
Airborne data are collected with the AWI Polar 5 and 6 aircrafts during the following campaigns: