Meteorology is by nature a multidisciplinary and transnational subject and COST cooperation has proved to be a flexible and suitable framework at European level for meteorological activities such as the standardisation of observation techniques and harmonised transmission of meteorological data. Although meteorology is not covered by a specific Community programme as such, various Community actions dealing with meteorology are now included in the EEC research programme on climatology (the "EPOCH" programme - 1989-92) of mechanisms of extreme and sudden concerning particularly the study meteorological events, in order to predict catastrophies and consequently to reduce human and material losses. In the context of COST cooperation, which is supported by the Commission of the European Communities, the COST 73 project (1986-1991) associates 16 countries in Western Europe with the aim of setting up a weather radar network providing real-time measurements of rain, snow or hail precipitations. In this project, radar data are transmitted and combined if appropriate with satellite data - in one or more "compositing centres" of the participating countries, in order to improve weather forecasting. Together with the COST 73 Management Committee, the Commission of the European Communities organized a seminar on this matter, in Brussels on 5-8 September 1989, at the half-way stage of the project.

Preface.- Opening Session.- Speech of Welcome.- Introductory Statement.- Session 1 - Radar Networking Programmes.- Cost-73: The Development of a Weather Radar Network in Wester Europe(Keynote paper).- The Prospects and Promise of NEXRAD: 1990's and beyond (Keynote paper).- Radar netwoking in Eastern Europe (Keynote paper).- A Nordic Weather Radar Network.- The Sao Paulo Weather radar network program.- The unified meteorological radar network of CSSR and central meteorological subsystem.- Une revue du programme ARAMIS.- The Weather radar network of the Deutscher Wetterdienst Progress Report.- Operational experiences with the Finnish Weather radar network.- Attempts in Hungary for Automation of Weather radar observations.- Overview of national and regional radar meteorological activities in Italy.- Overview of radar networking by MOC, Japan and its data dissemination system (FRICS).- Composite radar and satellite data processing in the meteorological system in Spain (A brief description of SIRAM project).- The United Kingdom weather radar network.- Composite weather radar displays.- ATC radar data networking in the Benelux and Northern Germany.- Weather radar networking: computing versus communications.- Transmission and visualisation techniques for a remote weather radar display.- Session 2 - The Role, of Reflectivity-Based Techniques in Operational Radar Networks.- Ways of using, and correcting for errors in conventional radar reflectivity data (Keynote paper).- Review of the telecommunications work of cost 73 project (Keynote paper).- Estimation of the areal coverage of radars and radar networks from radar site horizon data.- An operation system for display and analysis of hydrometeorological radar data.- Castor project improved processing of radar data in france.-Ground clutter reduction during rain measurements by a noncoherent radar system.- The operational use of a high speed interactive radar data processing system (RDPS) PART 1 : A Technical Description.- Siting of a weather radar network for operational hail suppression in Greece.- Sur la possibilityé de reproduire le facteur de réflectivité près du sol du champ tridimensionnel radar.- Session 3 - The Role of New Techniques in Operational Radar Networks.- New weather radar techniques: ready for operational use? (keynote paper).- Canada's Operational Doppler radar.- A Doppler Appliance to MRL-5.- Doppler Facilities for the UK MET Office.- Bright band errors in radar estimates of rainfall: Identification and correction using polarization diversity.- Rainrate measurements using a circular polarisation-diversity radar.- Session 4 - Combining adar, satellite and onventional meteorological data.- An integrated approach to the display of doppler radar and other meteorological data (Keynote data).- Near-real-time precipitation analysis over Europe.- Analyses of a mesoscale heavy rain system in the area of Beijing-Tianjin-Tangshan.- Real-time combination of radar and satellite data for very-short-period precipitation forecasting.- A professional meteorological information processing system.- Automating precipitation nowcasts based on satellite and radar imagery combined with numerical model products.- Session 5 - Meteorological and Otim Applications of Weather Radar Data.- The impact of radar and satellite imagery in a mesoscale nwp system (keynote paper).- PROMIS 600; An operational system for very short range weather forecasting in Sweden.- Radar for electrical studies and storm warnings.- The operational use of a high speed interactive radar data processing system - RDPSPart II : Application in real time severe thunderstorm detection and forecasting.- Determination cloud field evolution by the method of correspondence between radar reflectivity isosurfaces.- Comparision of radar precipitation measurements with a dence network of daily raingauges - Aplications to radar networking.- Session 6 - Hydrological and Other Applications of Weather Radar Data.- Practical applications of weather radar data in Europe (keynote paper).- Real-time forecasting: model structure and data resolution.- On the usefulness of weather radar data in real-time hydrological forecasting in Belgium.- A radar reflectivity-runoff model for use in flood warning.- The impact of weather radar on aspects of operational management in the thames region.- Feasibility studies on the use of the french "Aramis" radar network for hydrologic applications.- Radar data for hydrological users.- Urban hydrology and hail detection experiments made with a raingage-hailpad network and with a dual polarization radar.- Radar estimation of areal rainfall in switzerland - the genira project.- Agricultural use of weather radar data in Emilia-Romagna Italy.- Nowcasting for agriculture with the são paulo radar network.- The distribution of weather radar images to agricultural end users.- The use of weather radar data in road weather services: present and future needs.- Some Conclding Remarks.- List of Participants.- Index of Authors.