The Cloud and Aerosol Experiment at Åre (CAEsAR 2014) campaign took place from June to October 2014 at Mt. Åreskutan, Sweden, a remote mountain site in Northern Sweden. The campaign was designated to study the physical and chemical properties of clouds and aerosols.  A unique and comprehensive set-up allowed an in-situ characterization of both constituents at a mountain top station at 1200 m a.s.l. which included instruments to measure cloud droplet size distributions, meteorological parameters, cloud residual properties (using a counterflow virtual impactor inlet), cloud water composition and various aerosol chemical and microphysical properties (e.g. size, optical and hygroscopic properties). At the same time a remote sensing site was installed below the mountain site at 420 m (a.s.l.) in the direct vicinity. This site included instruments for vertical profiling like an aerosol lidar and a Doppler wind lidar; a Sun photometer measured aerosol columnar optical properties and a precipitation sampler sampled rain water for chemical analysis. In addition, regular meteorological soundings were performed from the valley.

 

View from the roof of the measurement station where inlets (PM10, CVI and total), cloud probes and the meteorological instruments were installed.

 

View from the side of the hut with the counter-flow virtual impactor inlet.

 

Inside the hut where a large suite of aerosol in-situ instrumentation are characterizing the chemical, microphysical and optical properties of cloud condensation nuclei and aerosol particles.

 

Set-up of remote sensing and in-situ instrumentation during CAEsAR 2014.

 

The Raman lidar (Polly XT) in action. The lidar was installed on the rooftop of the cable car station in the valley of Åre.

 

All Photos by Paul Zieger. For more information please contact Paul Zieger.

The first two master theses using observations from CAEsAR 2014 have been successfully concluded:

  • Vera Franke, Title: Quantification of organic and elemental carbon in airborne particulate matter at Mt. Åreskutan, Sweden
  • Therese Gadd, Title: On the optical properties of aerosol particles observed at Mt. Åreskutan, Sweden (together with MISU, see link)

Check out our time lapse movie of clouds developing at the site (click here).

Press coverage with a small video tour on Östersunds Posten can be found here.