meeting summary First International Short-Range Numerical Weather Prediction Workshop on Nonhydrostatic Modeling, 11-13 March 1996, Offenbach, Germany J. Steppeler Deutscher Wetterdienst, Offenbach, Germany 1. Introduction Several lead centers exist within SRNWP. Their aim is to increase the level of cooperation within the The First International Short-Range Numerical participating weather services in a particular area. Weather Prediction Workshop on Nonhydrostatic Deutscher Wetterdienst (DWD) has taken on the role Modeling took place from 11 to 13 March in of "lead center for nonhydrostatic modeling." Apart Offenbach, Germany; it is planned to be the first of a from being a forum of scientific exchange, the work- series of workshops. It offered a forum for all aspects shop sought to define the role of the lead center and of atmospheric modeling on a scale small enough that explore the potential of cooperation in this area on the nonhydrostatic models are necessary. These aspects international level. include model development, numerics, physical parameterizations, and applications of models, such as meso-a-scale forecasting, prediction of visibility, 2. Nonhydrostatic models available to or small-scale climate applications. The presentation SRNWP of methods that are currently used operationally with hydrostatic models but have potential for small-scale The section on nonhydrostatic (NH) models pre- modeling was encouraged. Even though the purpose sented five model systems that are currently prepared of the workshop was the development of operational or actually used for use in the practical work of applications, participation from universities and re- weather services. The meso-NH system of Meteo search institutes was encouraged. France was presented by J. Lafore and P. Benard The workshop was organized within the frame- (Meteo France). The model is capable of running for work of Short-Range Numerical Weather Prediction scales ranging from all mesoscales to microscale. This (SRNWP). SRNWP is a European initiative within model uses the unelastic approximation. All other the Network of European Meteorological Services models presented were fully elastic. Meteo France has (EUMETNET) with the purpose of searching for co- developed an alternative system, ARPEGE-ALADIN, operation in the field of numerical weather prediction. to be used in the next generation of numerical weather Participation in the workshop is not limited to Europe. prediction systems. T. Davies [U. K. Meteorological Participation in a cooperation is possible over a par- Office (UKMO)] reported on the unified model of ticipating weather service. Invitations to the workshop UKMO. It can be run in different modes (local area, were issued to the potentially participating weather mesoscale, global). Essentially the same code is used services as well as a number of individuals with an for all applications. The new Lokal-Modell (LM) interest in nonhydrostatic modeling. There were 59 by DWD was presented by G. Doms (DWD). This participants from 14 countries. model is supposed to run for scales of 10 km-10 m and will be the basis of the operational applications with the next model generation. Model applications will be daily forecasting, specialized model runs, Corresponding author address: Dr. J. Steppeler, Ableitung Meteorologische Analyse und Modellierung, Deutscher pollution modeling, and local climate applications. Wetterdienst, Postfach 10 04 65, 63004 Offenbach, Germany. J. Dudhia [National Center for Atmospheric Research In final form 10 September 1996. (NCAR)] reported on the model MM5. The model ©1997 American Meteorological Society contains a fairly complete physics package with sev- Bulletin of the American Meteorological Society 4 469 eral options. It can be used on workstations and is UKMO is pioneering this application, which has been used in several places to run real-time forecasts us- operational at UKMO since September 1994. The ing scales down to 9 km. The modeling system of the chemical prediction system EURAD (European Air Center for the Analysis and Prediction of Storms Pollution Dispersion Model) can predict the transport (CAPS) was presented by D. Jahn. The rather ambi- and the chemical transformation of pollutants over tious aim of this system is to use wind observations Europe. The model description and applications to of Doppler radars to initialize the model in order to pollution evaluation experiments in Europe have been predict thunderstorms. described by H. Jacobs (University of Cologne). The mesoscale modeling system of the University of Karlsruhe was presented by G. Adrian. It contains 3. Applications of nonhydrostatic models a comprehensive chemical transport system and was applied to the forecast of tropospheric ozone. J. Dudhia (NCAR) gave examples of applications F. Stratmann (University of Leipzig) described a sys- of the model MM5. In a number of places the model tem for the treatment of atmospheric aerosol using is used for real-time forecasting. It is also used for more than one mode. V. Pescaru (LDM, Bucharest) modeling of tropical and midlatitude weather systems, reported forecasts of pollution over Rumania using a regional climate studies, and data assimilation stud- Lagrangian puff model and forecasts of wind and tem- ies. A full physics adjoint of MM5 is available. The perature of the operational hydrostatic Europa-Modell usefulness of the variational approach in including of DWD. indirect observations was stressed. An application of the MM5 to the flooding of Piedmont was investigated by R. Ferretti (University of Aquila). Some initial re- 4.Technical aspects sults of the local model LM were presented by J. Steppeler (DWD). The results are very preliminary, In the section on dynamics and numerics, B. but they indicate that there may be some skill in the Machenhauer [Max-Planck Institute (MPI)] presented prediction of thunderstorms triggered by the small a new cell-integrated semi-Lagrangian method. This mountains over Germany. We plan to apply LM to the rather expensive approach has interesting conserva- observational campaign LITFASS (Lindenberg Inho- tion properties. An overview on different model for- mogeneous Terrain—Fluxes between Atmosphere mulations with respect to the pressure variable was and Surface: A Long-Term Study), where it will be given by H. Kapitza (Forschungszentrum Geesthacht). run using a scale of 100 m, to investigate the prob- R. Bubnova (Czech Hydrometeorological Institute) lem of downscaling. E. Heise (DWD) presented this presented plans to use the semi-Lagrangian (SL) project. J. Cuxard (Spanish National Institute of Me- method with the new ARPEGE-ALADIN modeling teorology) presented results of large eddy simulations system of Meteo France. She expressed hope that using a 3D turbulence closure level of 2.5, according problems of fictitious resonance will be overcome to to Mellor-Yamada. An analysis of sea breezes was such a degree that Courant numbers on the order of done by K. Born (University of Bonn). I. Mikkelsen three can be used. Since a decade ago there was gen- (Danske Meteorologiske Institut) compared radar ob- erally the expectation that Courant numbers of 10 or servations of gravitational waves with 2D model inte- more could be used, this means a strong reduction of grations. At the Norwegian Meteorological Institute, expectations over a long period of development. The rather finescale (5 km) dedicated-model forecasts are general nonhydrostatic dynamic of the ALADIN performed for special occasions, such as the 1992 model was presented by P. Benard (Meteo France). Summer Olympic Games in Barcelona. T. Nordeng A gridnesting scheme for chemical transport models [Norwegian Meteorological Institute (DNMI)] pre- was presented by R. Wolke (University of Leipzig). sented some results of such forecasts. O. Knoth (University of Leipzig) presented a new step An important application of mesoscale models is mountain approach intended for LM. the modeling of atmospheric pollutants. A system for In the section on data assimilation, D. Jahn (CAPS) forecasting visibility was presented by P. Clark presented the CAPS system of assimilating Doppler (UKMO). Observations of visibility and moisture are radar data by a 4D variational system. In comparison transformed into an aerosol field, which is forecasted with sparse global 4D analysis systems, the problem using the UKMO operational mesoscale model. is better posed since there is an abundance of radial 470 Vol. 78,, No. 3, March 7997 .