Scientists' Contributions

MAIN ACHIEVEMENTS OF COST CO-OPERATION IN METEOROLOGY

Sylvain Joffre, FMI, Finland

The atmosphere is a global common property in which weather systems and pollutants transcend national boundaries. It therefore needs to be monitored, understood and predicted, so that its impacts on society can be managed, through co-ordinated and dedicated international co-operation. Meteorological services are a fundamental component of the national infrastructure in all countries, contributing to the security and safety of citizens and serving socio-economic activities. They also advance the understanding of our atmospheric environment and provide reliable information suitable for various applications. According to several estimates, an effectively operating National Meteorological Service (NMS) can achieve an overall benefit-cost ratio system of at least 10:1.

Despite the long tradition of European co-operation in operational meteorology, there have been practical difficulties in co-ordinating research initiatives and in improving collaboration between NMSs, universities and industry. The setting-up of the COST framework in 1971 enabled a broader and more integrated co-operation between NMSs and other European research institutions in the field of atmospheric sciences. After the early years, there has been a continuous increase in the number of Actions, a widening of topics, greater inter-disciplinarity and integration of more countries and institutions, thereby enhancing dissemination of results and building national capacities.

COST co-operation in meteorology has had a successful impact from the very beginning as the first Action 70 (1971-1973) led to the foundation of the European Centre for Medium-range Weather Forecasts (ECMWF). Nowadays, ECMWF has achieved a strong world-wide reputation as a lead centre of excellence for weather forecasting and for cutting-edge research in the field of numerical weather prediction (NWP).

Moreover, most COST Meteorological Actions have collaborated with international organisations such as the ECMWF, the UN World Meteorological Organization (WMO), the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the European Space Agency (ESA) and with EUMETNET (a European network of NMSs). Such collaboration has given additional benefit to operational practices through cost-effective transfer of innovative science.

RADARS: From Research Instruments to Operational Networks

The first COST Actions dealt with radar techniques and wind profilers, reflecting the emerging interest in the new remote sensing technologies. Weather radar data is essential for very short-term forecasting of weather hazards such as heavy precipitation, for assessing flooding risks and planning preventive measures. Actions COST-72 ('Measurement of Precipitation by Radar', 1979-84) and COST-73 ('Weather Radar Networking', 1986-91) demonstrated the feasibility and cost-effectiveness of a European weather radar network and the viability of data exchange. These two Actions provided the stimulus for a rapid increase in the operational deployment of weather radars in Europe, passing from a single system in 1974 to over 140 systems by now. They were subsequently organised into regional networks with the pre-normative work done on data transfer protocol channelled into WMO guidelines. Standardisation requirements created by these Actions have proved very relevant for the industry.

Subsequent technological developments (Doppler, polarimetric and other multi-parameter facilities) stimulated a thorough review of the utility and viability of these new systems in COST-75 ('Advanced Weather Radar Systems', 1992-97). This led to recommendations for improving and harmonising processing procedures and resulted in common specifications for the next generation of weather radars of the European network. COST-75 was the driving force that led NMSs to develop an operational administration of radar network data. Through these efforts, the European radar community has reached a prominent position in the field of radar meteorology. COST-75 also launched a series of biennial open European conferences (ERAD) in order to maintain the momentum and networking it had initiated.

Wind profiler radars have the capacity to estimate continuously and in all weather conditions the three components of wind up to altitudes between 5 and 25km, depending on the system used. This is a clear advantage compared to balloon observations performed routinely only twice a day. A network of European wind profilers would be a valuable tool for improving detailed weather forecasts. COST-74 ('Utilisation of VHF/UHF Radar Wind Profiler Networks for Improving Weather Forecasting', 1987-1991) generated wind profiler radar specifications. Moreover, the Action began the process of requesting from the UN International Telecommunication Union allocation of frequencies needed for the operational use of wind profilers. The follow-up Action 76 ('Development of VHF/UHF Wind Profilers and Vertical Sounders for Use in Observing Systems', 1994-2000) achieved the allocation of frequencies, and established a semi-operational European network of about 15 wind profilers with a hub for data collection, quality control and data distribution. The Action finally made recommendations for the conversion of this network into a fully operational structure. Such systems can be used also for monitoring the atmospheric boundary layer. COST-76 then proposed the new Action 720 ('Integrated Ground-based Remote-Sensing Stations for Atmospheric Profiling', 2000-2005) which considers integration of various remote-sensing techniques at a single station by exploiting the synergy of the combination both to improve quality control and provide data on all the most important atmospheric parameters.

It is noteworthy that industry participated actively in several of these Actions both in research and in the assessment of techniques and methodologies. This led to a better mutual understanding about demands and technical possibilities.

Enhancing the Use of Satellite Data

Research and development on remote sensing from satellite platforms were the core activities of Actions 712, 714 and 716. At the start of COST-712 ('Microwave Radiometry', 1996-2000), the high potential of microwave imagery for providing information on the Earth's environment was far from being fully exploited and interactions between users and researchers in Europe were weak. Development of microwave radiometry is very delicate due to the wide range of parameters influencing the data. Through COST-712, for the first time in Europe, experts on microwave remote sensing technology, data and modelling joined experts on atmospheric sciences to advance the application of microwave radiometry from space. COST-712 assessed some of the processes of radiative transfer models, the basic tool for retrieving and interpreting remote sensing data, and provided recommendations on necessary developments and for applications of these models. One significant success was to help identify the microwave radiometer as the most important single source of data influencing the skill of numerical weather predictions.

Observing and forecasting the state of the sea is a major challenge with various practical benefits for the safety of maritime activities and the sustainable development of the coastal zone. Developments have been hampered by the gap between the research community and the users: mainly the port and maritime authorities and engineering companies. Against this backdrop, COST-714 ('Measurement and Use of Directional Spectra of Ocean Waves', 1996-2001) contributed to the improvement of methods for retrieving information on the state of the sea from satellite data and developed alternative measuring systems. It also defined strategies for new field experiments and for new analysis of data. Various users have so far collected sea-wave data in a completely unstructured manner. COST-714 managed to put on the Internet a database giving the various data formats and providing recommendations for data access. The Action was also able to launch an interactive dialogue between the two communities through dedicated conferences under the aegis of UN-organisations, UNESCO and WMO.

The Global Positioning System (GPS) is designed for global navigation. However, if the position of the GPS receiver is already known, the signals can be used to study the atmospheric influence (mostly by water vapour) on the signals from GPS satellites. By bringing together space geodesists and meteorologists, COST-716 ('Exploitation of Ground-based GPS for Climate and NWP Applications', 1998-2003) aims to assess on an international scale the operational potential of ground-based GPS receivers for providing near real time observations for NWP and climate research applications. The continuity and density of GPS data make them very suitable for monitoring rapidly evolving, small-scale storms. COST-716 will develop and demonstrate a prototype system together with a data exploitation scheme for NWP. Another advantage of such a system is that it can provide stable humidity observations over decades, allowing detection of long-term climatic trends.

Operational Forecasting

A current trend in weather forecasting is towards tailor-made products for various local users involved in transport by air, sea or land, farming, energy distribution, tourism, sports and local outdoor events, water-management, construction, etc. These require a combination of high-resolution observational techniques, efficient standardised data analysis and modelling. Many of these products are of high economic value and fall under the label of nowcasting techniques, i.e. they provide a detailed state of the atmosphere up to 6-12 hours ahead. Moreover, developments for visualisation and dissemination to end-users by multi media devices are increasingly needed. Since such activities are predominantly operational, developments have usually been ad-hoc and local without much involvement of the R&D departments.

COST-78 ('Development of Nowcasting Techniques', 1994-99) was able to fill this gap by reviewing various approaches, identifying strengths and weaknesses and providing recommendations for further development at European level. Results from COST-78 have led to better monitoring and forecasting of extreme weather, such as thunderstorms and heavy rain, that increasingly produce disasters in various European regions. COST-722 ('Short-range Forecasting Methods of Fog, Visibility and Low Clouds', 2001-06), following on from Action 78, will develop new methods, models and software for situations of poor visibility where local topographical, climatic and environmental conditions are important.

It is a major theoretical, technical and operational challenge to use effectively the huge amounts of radar data now available for improving weather forecasts or for validating our understanding of atmospheric processes. Thus, COST-717 ('Use of Radar Observation in Hydrological and NWP Models', 1999-2004) is examining the requirements on European radar data for their wider use in hydrological and weather prediction models. The work will also lay the basis for using radar data effectively in the validation of process description in these models.

Modern outdoor lifestyles together with ozone depletion have raised concerns about the increased exposure of humans to UV-B radiation with, consequently, the increased risk of developing skin cancers. One essential service is thus to provide information on UV-B for public awareness in a standardised manner so that tourists and the local population can benefit equally from this information throughout Europe. Forecasting UV-B strongly depends on forecasts of cloudiness and ozone concentration. COST-713 ('UV-B Forecasting', 1996-2001) assessed various models for UV-radiation computation and identified conditions under which they are most accurate, and laid the foundation for an improvement of UV forecasts. In co-ordination with WMO and the World Health Organization, it also provided guidelines for achieving a harmonisation of the UV index. The Action also produced in several languages a very illustrative booklet to further public education on practical UV issues.

Agrometeorological and Climatological Services

Aiding weather-sensitive farming activities has been and remains an important application of meteorological information. The modern requirement for tailor-made products necessitates the use of sophisticated models, remote sensing methods and dedicated forecasts to provide specific information on a fine spatial scale. The gap between advisers, users and meteorological services has hampered the interpretation and dissemination of the required information. These considerations were the main reasons for the launching of three co-ordinated Actions (1994-98) in the field of agrometeorology: COST-77 ('Application of Remote Sensing in Agrometeorology'), COST-79 ('Integration of Data and Methods in Agroclimatology') and COST-711 ('Operational Applications of Meteorology to Agriculture, incl. Horticulture'). These Actions allowed first assessments of the practices, needs and gaps in the services provided, and tested new methods and models able to provide relevant information. Based on this newly established networking, a follow-up Action COST-718 ('Meteorological Applications for Agriculture', 1999-2004) is addressing some urgent identified needs, such as the testing and implementation of models for crop yield, irrigation and pests and diseases. It will assess the availability of meteorological data for agrometeorological models and will aim at improving the communication channels between the two communities.

The mapping and analysis capabilities of Geographic Information Systems (GIS) are increasingly employed in climatology, meteorology and other geosciences as well as by governance authorities especially for environmental and land-use applications. Typically, such studies are multidisciplinary and require the combination of data from several agencies and the use of spatialisation and other complex analysis techniques to extract patterns in space and/or time. There is now a strong need for improving ease of data exchange between disciplines as well as expert assessments of the state of the art of GIS tools. COST-719 ('The Use of GIS in Climatology and Meteorology', 2001-2005) will address these concerns, develop applications and places particular emphasis on standardising where possible. Results of the Action will be dissemination of GIS expertise on a European scale.

Air Quality and Pollution Control

European legislation on air quality requires monitoring and assessment of pollution level over national territory. This requires use of meteorological dispersion models that should be comparable since pollutants cross borders and pollution control values are the same throughout Europe. With this perspective, COST-710 ('Harmonization in the pre-Processing of Meteorological Data for Dispersion Models', 1994-97) performed intercomparisons of sub-models that compute the sophisticated dispersion parameters needed for the advanced models from simple routinely measured meteorological quantities.

A subsequent Action, COST-715 ('Urban Meteorology Applied to Air Pollution Problems', 1998-2003), is addressing the specific problems of urban meteorology, as 70% of Europeans live in cities. Cities present specific problems for the science of meteorology as they cause strong modifications to conditions prevailing in surrounding rural areas and generate a microclimate of their own. Furthermore, most meteorological measurements are made at rural or airport sites. Consequently, one has generally no representative meteorological indicator of prevailing conditions either over the city or within its complicated building canopy. COST-715 aims at defining practical criteria (e.g., interference-free reference height and location surroundings) for performing such measurements in cities which, it is expected, will become WMO guidelines. COST-715 also addresses the problem of the wind field under stagnant wind conditions, associated with episodes of strong pollution, when neither measurements nor operational NWP models provide clear indication of the flow patterns. For the first time, there is an opportunity to harmonise techniques for predicting such episodes. This Action has caused a reawakening interest in urban meteorology, especially in NMSs, and an awareness of the limitations of many commonly-made assumptions.

New Challenges Require Co-ordination through Co-operation

The flexibility and complementarity of the high-quality science performed under COST have been demonstrated in the field of meteorology and have contributed to many achievements that would not have been possible otherwise. Research and development as well as interdisciplinary co-operation in the field of meteorology, climate and atmospheric sciences will certainly increase as the subject responds to wider and deeper needs of society. For instance, many of the major environmental issues such as climate change, ozone depletion and acid rain have the atmosphere as the main stage. Besides, many socio-economic activities (e.g., transport, land-use, agriculture, energy production, tourism) are becoming increasingly sensitive to weather and climatic conditions and thus dependent on meteorological services and information. Authorities need these services also to react promptly to emergency conditions caused by natural hazards (e.g., floods, landslides, avalanches, droughts, storms, icing), or industrial accidents (e.g., hazardous chemical releases, dispersion of radioactive compounds). Thus, COST will continue to be a useful mechanism for boosting research activity on key topics for society, ensuring standardisation and disseminating expertise on a European scale. Participation in COST provides an essential support, impetus and training ground for R&D activities in atmospheric sciences and their applications in Europe.