Numerical Simulation and Analysis on the Phoenix Typhoon Rainstorm Using WRF
Rainstorm caused by the Typhoon Phoenix, between July 28th and 31st 2008, is studied by using the meso-scale numerical simulation model WRF and some NCEP reanalysis data of 1¡ã¡Á1¡ãwith 6h interval. Results show that, the distribution of the SLP, wind and rain belt was simulated successfully by the WRF model. The research shows that the strong upward motion at the 600 -700hPa and 100 -200hPa of 24¡ãN and two closure centers of near 21¡ãN-22¡ãN and 31¡ãN-33¡ãN at the high troposphere induced convective cloud cluster to develop.
2 NUMERICAL WEATHER PREDICTION 2 Numerical weather prediction
National meteorological services are required to provide short and medium range weather forecasts, warnings and alerts for their territory. Modern-day weather forecasting is highly relying on numerical weather prediction (NWP). The medium range forecasts are produced with global models using the whole of Earth as a domain having a horizontal resolution of about 20-40 km. For short range applications it is more efficient to run the NWP systems for only a small part of the globe using a Limited Area Model (LAM) operating on smaller scale grid and using boundary conditions from global models. [Nie06] In Europe there are a number of consortia that collaborate on Limited Area Modelling. The High Resolution Limited Area Modelling project HIRLAM was the first group to be established in the Nordic Countries in 1985. It has expanded to include other countries in Western and Southern Europe and it has been a successful collaboration programme. The developments of earlier projects are carried over and further developed in new projects. In January 2006 the programme advanced to a new phase called HIRLAM-A, which inherited all the knowledge from previous HIRLAM-6 project and its predecessors. The main objectives, targets and priorities of each project are listed in a memorandum of understanding, which is available at HIRLAM webpage www.hirlam.org. In addition to developing the HIRLAM model, the programme targets to provide and maintain NWP expertise among the HIRLAM members, enhance collaboration both between scientists in the HIRLAM institutes and with co-operating consortia and with other NWP groups. The HIRLAM forecast system is at the moment used in routine weather forecasting by several European NMS including Finnish FMI. [HIR06] A NWP-system comprises two main components, which are the atmospheric model and the data assimilation system. The atmospheric model is further divided into two main parts: the model dynamics and the physical parameterization [Nie06]. In this paper, the basics of NWP modelling are presented via the High Resolution Limited Area Modelling project HIRLAM.
D'une application pratique des indices bio-météorologiques
Abstract The purpose of the author is to determine statistically in what part of Switzerland maize could be cultivated with certain chance of rentability. The author gives first the method he used for determining the biometeorological index of four species of maize which were selected by the Swiss agronomical research stations. He has considered two possibilities for the growing period: ( a ) raising-ripening (l'approche globale); ( b ) raising-flowering, flowering-ripening (l'approche fractionee). From the biometeorological index, he calculated retrospectively the ripening time of these four species in the years 1901–1965. Assuming a priori that maize should be harvested before October 15th at the latest, he calculated, for a number of meteorological stations, the relative number of years when such conditions were fulfilled. Dividing the country in regions of similar mesoclimates and sorting these stations per region, it is possible to average the maximum altitude where maize can ripen at least 7, 8, 9 and 10 times within 10 years. Finally, taking into account the exposure and ground slope, he draws maps of the theoretically possible extension area, which maps are more reliable and detailed than the ones derived from actual means.