The field experiment BASIS 2001 took place in the Gulf of Bothnia of the Baltic Sea. The Finnish Research Vessel Aranda kept a fixed position in the pack ice and was a base for standard meteorological measurements and radiosonde ascents. Surface measurements were also taken at four land stations (Marjaniemi, Oulu, Kuivaniemi, Haparanda). The research aircraft DO-128 of the University Braunschweig performed 10 flight missions.

The BASIS experiments as well as ALKOR 2000 and 2001 are part of the research compound BALTIMOS (BALTic sea Integrated MOdel System). BALTIMOS in turn is part of the Baltic Sea Experiment (BALTEX).

The overall objective of all eight field experiments (BASIS and ALKOR) was to collect a comprehensive data set suited to validate the coupled model system BALTIMOS for the Baltic Sea region. The observations mainly focus on:

- the atmospheric boundary layer structure and processes and the air-sea-ice interaction over areas with inhomogeneous sea ice cover

- the atmospheric boundary layer structure over open water under different synoptic conditions such as cold-air advection, warm-air advection or frontal passages.

In addition to the published datasets several other measurements were performed during the experiment. Corresonding datasets will be published in the near future and are available on request.

Details about all used platforms and sensors and all performed measurements are listed in the fieldreport.

The following datasets are available on request: meteorological station Marjaniemi and Oulu airport, ground data at RV Aranda, 10 flights of research aircraft DO-128