Project: Field Data of the Meteorological Institute, University of Hamburg - The Physical Meteorology Division of the Meteorological Institute is regularly conducting or taking part in field experiments with strong focus on high latitudes. Measurements are performed by aircraft, radiosondes or buoys and at land, ship and ice stations. Published data sets incorporate aircraft measurements of turbulent fluxes and standard meteorological parameters of high temporal and spatial resolution. These measurements are supported by frequent radiosonde ascents and station and ship data in the according region. Another group of data sets consists of measurements by autonomous buoys of different complexity on sea ice and ocean. Summary: The field experiment FRONTEX 1989 (FRONT EXperiment) took place in the German coastal area of the North Sea between 2 May and 6 June 1989. It was coordinated by the Meteorological Institute of the University of Hamburg and was primarily funded by the German Research Foundation (DFG) in the frame of the priority programme "Fronten und Orographie". The scientific aim was the investigation of cold fronts moving in from the North Sea and reaching the coastal area. The different physical properties of sea and land surface (roughness, humidity, temperature, heat conduction and heat capacity) modify the frontal structure at landfall. The modification should first alter the boundary layer and is then communicated to higher levels, thus effects like convection and convergence will be found farther inland. The experimental concept was to monitor the passing front on all relevant temporal and spatial scales. To obtain this goal a large variety of measurement platforms was employed. Ground based remote sensing and in-situ measurements were performed at Heligoland, Schleswig, Hanover, Emden, Berlin, and on board the research vessel. Three research aircraft (POLAR-2 and POLAR-4 of AWI Bremerhaven and DO-128 of TU Braunschweig) were used to measure the frontal structure with high temporal and spatial resolution.