【正文】 time of observational data, and the forecast leadtime depends on those of the model and the radar precipitation nowcasting. Four forecast strategies are proposed: A. Model: It is initialized at 00 and 12 UTC and actualization is between 4 and 6 hour after initialization. In other words, for verification time at 00 UTC, a model run is chosen at leadtime 12 hour of the runs initialized previously at 12 UTC. On the other hand for verification time at 06 UTC, the model run is chosen from the runs initialized at 00 UTC. B. Model tendency (Mtendency): Tendency is referred to as the forward changes of model temperature in time (176。 grid spacing.Numerical weather prediction model: The model output for the surface is generated over the Iberian Peninsula by meteoblue AG, a private pany that runs NMM (Nonhydrostatic Mesoscale Model [2]) in 13km spatial resolution twice a day with 1hour forecast up to 72 hours. Analysis of potential snow areaThe PSA is determined mainly based on temperature (obtained from both model output and surface stations) and precipitation (obtained from radar reflectivity and/or model output) at nearground level. The algorithm interpolates each input field onto the mon grid with 176。gic de Catalu241。a including 1) terrain height from DEM, 2) temperature from model, surface station, soundings, and 3) radar reflectivity. The deployment of the observational sources is shown in Figure 4 overlaid on orography. More detail on each source is provided in the following points. Figure 4. Data available around Barcelona over orography: Crosses indicate the location of CDVRadar and Airport Barcelona. Similarly, large diamond for AEMET surface stations, small diamond for SMC surface stations, and triangles for soundings.Digital elevation model (DEM) data used here are from ASTER GDEM (Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model1) which has a horizontal resolution of 1 arcsecond, both in longitude and in latitude. This highresolution terrain height is remapped with a grid spacing of 176。Celsuis) embedded in colder (T 0176。2Hydrometeorological Innovate Solutions ., Barcelona, SpainEmail: ABSTRACTRecent developments are reported on techniques to determine the onset, duration, amount and type of precipitation as well as the snow and icing conditions at the surface. The algorithms, still under development, will be used to forecast the weather in short to medium lead times, . for the next 30 minutes up to a few hours (“nowcasting”). An algorithm aims at detecting potential areas of snow fall by bining reflectivity data of precipitation and surface temperature data from a numerical model as well as surface stations in high spatial resolution. Another approach bines profiling measurements with numerical weather forecast products. (., meteo data measured by aircraft and polarimetric radar data)Keywords: type and amount of precipitation, nowcast, anticipating the weather 1 INTRODUCTIONWeather phenomena contribute to congestions, accidents and delays in all traffic modes. The road traffic in particular is derogate by adverse weather like snow, ice, fog, rain, strong wind and wind gusts. Increasing traffic makes transportation even more vulnerable to adverse weather conditions. Today stakeholders and participants in transportation (be it airborne or groundbased) most of the time only react on adverse weather when the disruption has already happened or is just about to happen. Future road management systems should proactively anticipate disruptive weather elements and their time scales of minutes to days well in advance to avoid or to mitigate the impact upon the traffic flow. But “weather” is not a technical problem that can be simply solved. Predicting the weather is a difficult and plex task and only possible within certain limits. It is therefore necessary to observe and forecast the changing state of the atmosphere as precisely and as rapidly as possible. Moreover, measures are required that translate “weather” to “impact” and minimise those impacts on traffic flow and its management. To inform traffic participants and traffic management centres in due time on (expected) adverse conditions, tailored and accurate meteorological information is required on short notice. This information must be integrated in the process of information distribution and decision making to allow for tactical as well as strategic decisions. The Institute of Atmospheric Physics of the Deutsches Zentrum f252。附錄 (英文)Tailored and Ontime Winter Weather Information for Road Traffic ManagementThomas Gerz, Arnold Tafferner, Shinju Park, Felix Keis11 Institut f252。r Luft und Raumfahrt, Oberpfaffenhofen, Germany。 snow conditions at the surface one has to consider weather changes due to advection of air with different characteristics and, especially demanding, possible changes resulting from precipitation and cloud physics processes which can occur within short time spans at the observation site. For capturing both of these effects an approach is followed where WWOs are determined at the various observation sites around an airport or along motorways where data from SYNOP, radar and SWIS stations are available. Chan