COST 733: Weather type classification and precipitation gridding

Weather type classifications provide a simplified albeit incomplete description of the atmospheric state. Classifications used throughout Europe differ widely in the classification method, the geographical domain they are tailored to, the meteorological parameters they are based on, and the number of types. This hampers a systematic comparison and evaluation. Moreover, weather types are traditionally derived manually and depend on the personal expertise of those who carry out the classification. This may introduce spurious temporal inhomogeneities in the classifications and calls into question their use in climate analyses.
The COST Action 733 is a coordinated European effort to overcome these limitations. The objectives of MeteoSwiss within COST 733 are twofold. First, automatic classifications are to be identified that represent climate variability in the Alps particularly well. This will provide the scientific basis for the planned replacement of the currently operational manual classifications by an automatic method. Second, it is examined if and how weather-types can be exploited as supplementary information for spatial precipitation analysis. This aims at improving real-time analyses from measurements at the coarse network of automatic rain gauges.