The objective weather type classification of the German Weather Service and its possibilities of application to environmental and meteorological investigations

The objective weather type classification of the German weather service and its application possibilities are described. Meteorological criteria for this classification are the advection of air masses, the cyclonality and the humidity of the troposphere, leading to numerical indices from which the weather types are derived. The data basis is the numerical weather analysis and forecast system of the German Weather Service. A time series of the weather type data covering more than 20 years is available now. The classification area is Germany, in principle it can be transferred to other areas as well. There are 40 different weather types, but the numerical indices provide the possibility to enlarge or to reduce the number of types without changing the meteorological criteria. This makes the classification very flexible for individual users. Various applications of this weather type classification are listed. A regularly weather type monitoring via INTERNET has been realized.