Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment — SALTRACE

The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment — SALTRACE — is a German initiative to investigate the long-range transport of Saharan mineral dust across the Atlantic Ocean into the Caribbean. The experiment combines ground-based and airborne in-situ and lidar measurements with meteorological data, long-term measurements, satellite remote sensing, and modeling.
SALTRACE is split into three field experiments at Barbados. The first one was conducted from June to July 2013 (wet season), another one in February 2014 (dry season) and the last campaign from June to July 2014.

Large eddy simulations for several cases during the campaign are performed with ASAM. The initial atmospheric state is obtained via nighttime radiosonde profiles.
Since non-cyclic boundary conditions have to be used to simulate the island-ocean-system around Barbados, turbulence near the inflow is generated with a novel method based on potential temperature perturbations. With that, a realistic marine boundary layer is formed before interacting with the island, which develops its own internal boundary layer. The main objectives of this study are to investigate local island effects on

  • the modification of the boundary layer structure,
  • microphysical properties,
  • the development of cloud streets and
  • downwind vertical mixing of aerosols (mainly Saharan dust).
  • Downwind profiles and velocity spectra are compared with the results from pure marine boundary layer simulations (without island and with periodic boundary conditions). Furthermore, model results are compared with wind lidar profiles taken from the FALCON research aircraft over and around Barbados during the first summer campaign.