Extreme Precipitation in the European Arctic in Summer: Statistics and Synoptic Models

Extreme precipitation in summer is classified in terms of belonging to the certain baseline probability distribution. The Pareto distribution can be used as its approximation. Events deviating from the baseline distribution are represented by the largest daily total precipitation. For them, the compliance with the probability (or the average repetition time) is completely lost, that is, any anomalies can occur, but they do not exceed some limit values typical of the Arctic. Thus, for the entire set of extremes, a specific distribution law of random variables can be introduced, that describes anomalies not exceeding certain absolute values; the presence of the boundary is felt only when approaching it. For 50 analyzed years at each station in the European Arctic, approximately four such anomalies were recorded. Synoptic objects in which super-large precipitation anomalies occur are determined: these are cyclones or pressure troughs with high water vapor content in the air (exceeding 25 kg/m 2 ) and with mesoscale systems embedded into the fronts, which are characterized by the vertical wind shear.