Source Analysis of Greenland Air: understanding the transport regime between the FT/BL and the surface

The poles are said to be the barometer of the planet and it is critical we understand the processes which are impacting them at this time. The melting of the Greenland icesheet is estimates to have contributed to 16% of planetary sea level change since the early 1990s.

The warming/cooling effect of arctic clouds are in a very fine balance, optically thin clouds can impose a measured warming as was observed in summer 2012 when an optically thin layer persisted over the Greenland icesheet for a period, the layer was sufficiently insulating that the surface layer warmed causing an unprecedented melt across the entire icesheet, estimated at close to 100% of the icesheet was above 0 °C for several days.

There are many hypotheses as to the range of and sources of the atmospheric aerososl which contribute to the budget of so called cloud condensation nuclei (CCN) and Ice Nucleating Particles (INP) which for the ‘seed’ for cloud formation.

In early 2019, a major NERC/NSF initiative; Greenland Aerosol Cloud Experiment (GrACE) will begin to make some of the most comprehensive coupled observations of aerosols and clouds on the icesheet. Coupled to GrACE, this project will undertake a comprehensive study of the airmasses which impact on the icesheet identifying case studies for closer inspection. We will use back trajectory analysis to develop an airmass history profile. From this we can develop climatologies to understand the influences of different airmass profiles, we know that “local” air impacts the icesheet and that complex circulation patterns exist, coupled to the barrier to downward mixing effected by the boundary layer clouds that are often found over the icesheet.

During the field observational phases aerosol samples will be collected at the surface as well as deploying the Leeds SHARK airborne sampler and remotely piloted drones to collect samples both within the boundary layer and in the free troposphere above. These will be used to allow us to understand the transport regime between the FT/BL and the surface. Alongside the aerosol measurements, surface samples will be collected during the 2019/2020 fieldseasons for isotopic analysis at the CASE partner (Prof Liane Benning, GFZ, Potsdam), these will provide further evidence to the aerosol sampling. There will be the opportunity to participate in fieldwork during summer 2020 based at the NOAA/NSF research base at Summit in Greenland.