Precipitation Extremes and Their Synoptic Models in the Northwest European Sector of the Arctic during the Cold Season

Abstract

Precipitation extrema over the Barents Sea and the neighbouring locations in Europe were analysed using data obtained from station observations and a highly detailed ERA5 re-analysis dataset. These data did not always spatially coincide (on average, coincidence was ~50%). Daily amounts of precipitation were typically higher in the observation data, although there may be a reverse picture. The analysis revealed that at several stations and in many of the ERA5 grids, the set of precipitation extremes exists as a mixture of two different subsets. The cumulative distribution functions (CDF) of the largest population in the context of both the re-analysis and observational data are well described by Pareto’s law. However, very rare cases exist in which the values deviate and exceed this base distribution value in regions possessing large values. These super-large anomalies do not obey the statistical law common to all other extremes. However, this does not mean that the extremes can be arbitrarily large. They do not exceed the marginal values that are typical for this type of climate and season. The analysis confirms that extreme precipitation in the western sector of the Arctic is caused by the penetration of moist air masses from the Atlantic in the circulation systems of intense cyclones. At certain times, mesoscale convective systems are embedded in atmospheric fronts and can significantly contribute to the formation of precipitation. Intensification of such cyclones corresponding to global warming should lead to a transformation of typical CDF, as modern outliers will become regular components of the Pareto law. This change in the statistics of extreme events reflects the nonstationarity of the climate state. The influence of polar lows on the formation of large daily precipitation amounts is not felt.

A Spatially Detailed Projection of Environmental Conditions in the Arctic Initiated by Climate Change

“…This suggests that the empirical tail diverges from the base model, indicating that different models may describe the data well. While such extreme events are rare, their presence has significant implications, as they represent the greatest extremes [8,9]. Nevertheless, when information is averaged monthly, the contribution of such exceptionally rare events is not felt.…”

“…Climate change directly affects the statistics of extreme events [8,9] and climatically driven phenomena, such as frosts and thaws [10], as well as avalanches and slush flows [11]. In combination with climatically-induced permafrost destruction, these changes can lead to important modifications in events, such as mudflows, cryogenic landslides [12], abrasion [13,14], erosion [15], suffusion [16], frost heave [17], solifluction [18], thermokarst [19], and others.…”

First Record of the Northern Wolffish Anarhichas denticulatus Krøyer, 1845 (Anarhichadidae: Zoarcoidei: Perciformes) in the Siberian Arctic: Further Evidence of Atlantification?

“…The consequence of this influence is the elimination of differences in oceanic conditions between some Arctic areas and the North Atlantic [4][5][6][7][8]. This phenomenon has been described as Atlantification in the scientific literature [3,5,7,8], or less frequently, Atlantisation [9,10]. At the physical level, Atlantification manifests itself in the Arctic Ocean as increased advection of heat carried by 2 of 16 Atlantic Ocean waters, an increase in air and water temperature, a reduction of ice cover, earlier dates of ice retreat, a decrease in freshwater intake, and an increase in salinity [3,5,6].…”