Regional features of glaze ice events frequency in the north of the European territory of Russia in the current changing climate

Recently, the interest in society in observing and forecasting dangerous meteorological phenomena in the cold period of the year has noticeably grown. In this work, we study the phenomenon of glaze ice in the north of the European territory of Russia in the North-Western Federal District. Here glaze ice (icing) is less frequent than other forms of ice accretion, but its characteristics most often exceed the criteria of dangerous meteorological phenomena. It is a great danger for various areas of the economy, ship navigation, causing an increase in traumatism of the population and damage to infrastructure. In accordance with the aim of the work, the spatial and temporal variability of the frequency of glaze ice accretion on the territory of the North-Western Federal District in the period 1986–2022 is investigated. The results are obtained on the basis of instrumental observations of meteorological stations. Using statistical analysis, the features of mean yearly frequency at each meteorological station were studied. To assess the direction of annual changes in the glaze ice frequency, the linear trend coefficient was calculated for each meteorological station. The least squares method was used for this purpose. It is shown that the maximum number of days with glaze ice occurs in the central part of the North-Western Federal District. This can be attributed to the more frequent movement of Atlantic and southern cyclones to high latitudes and their precipitation, especially at the atmospheric fronts and in the warm sectors of the cyclones, at air temperatures near zero and below. What makes the spatial distribution of glaze ice frequency even more uneven is the presence of uplands in the European territory of Russia. More precipitation falls on their windward slopes, and the temperature decreases with altitude. The findings show that in recent decades there has been an increase in the frequency of the glaze ice phenomenon in the region. At the same time, the interannual variability remains relatively constant. Taking into account the positive trend in the number of glaze ice events and increasing air temperature and precipitation, it is necessary to develop measures to deal with this hazardous phenomenon and minimize damage from it.