The GKSS Forschungszentrum Geesthacht GmbH (GKSS) is one of 16 national research facilities belonging to the Hermann von Helmholtz Association (HGF). GKSS has two sites at Geesthacht near Hamburg and Teltow near Berlin with a total staff of approximately 750 employees, including about 480 scientists, engineers and technicians. The three main GKSS research areas cover materials science, environmental research, and separation processes using membrane technologies. Major research facilities at GKSS include the Geesthacht research reactor (FRG-1), which is used as a source of neutrons for research purposes, extensive experimental and testing facilities, pilot plants, mainframe computers, and a research vessel. GKSS comprises 5 research institutes, and its organisational structure is based on a flexible matrix system and project management principles both of which promote networking of GKSS's activities internally and in particular with external partners. The latter include research institutes, universities, communities, private and public companies at both the national and international levels. Research at GKSS is problem-oriented and covers basic as well as applied research. About 85 % of GKSS's annual budget is provided by the federal and states governments, while 15 % are generated via EU and national research projects, contract research, and licensing of GKSS patents for products and processes. GKSS maintains central administrative, financial and legal departments providing for full support to its researchers in all related issues. GKSS has year-long experience and a successful tradition in both the co-ordination of and participation at different sorts of EU research projects; in early 1999 researchers at GKSS have been participating in some 40 EU research projects.

The work proposed here is carried through in the Institute for Atmospheric Physics, which gained relevant experience in the former cloud-radiation experiments ICE and EUCREX and other related experiments; it is also involved in cloud and heat budget analyses from satellite data. The institute comprises working groups on numerical modelling, satellite remote sensing and cloud processes, i.e. cloud radar and in-situ particle measurements. It is one of the nuclei for the BALTEX programme and hosts the international BALTEX secretariat. The institute participated in and partly coordinated several EU and ESA projects, i.e. a space-borne cloud radar study. Since 1996 its department of Atmospheric Measurements operates a 95 GHz cloud radar which has been used for several process studies and contributes to the international projects CARL (EU) and CLARE’98 (ESA).