Dominant types of ice accretions according to observations at Ob’ Bay stations

Abstract

Modern global climate change is accompanied by an increase in the number of hazardous hydrometeorological phenomena. At the same time, especially rapid warming is observed in the Arctic zone of Russia — 0,71 °С per decade. For this reason, research related to the study of hazardous hydrometeorological phenomena is becoming especially important for the northern territories of Russia, where oil and gas production is currently being intensified, which also increases the main environmental risks. Given the growing interest in hazardous weather phenomena, as well as the need to prevent and reduce negative impact on various sectors of the economy, there is a need for a more detailed study of atmospheric icing. In this study, the aim was to investigate the spatial distribution of ice accretions, which include glaze ice, soft rime, hard rime and wet snow. Also, the work considered the seasonal course of the observed ice accretions and assessed the trend in the number of atmospheric phenomena leading to atmospheric icing for the period from 1966 to 2021. To study the prevailing types of ice accretions, data from visual observations of atmospheric phenomena were used. To study the time trend of ice accretions, the data of 3-hour observations were used. For each of the 7 selected meteorological stations in the Ob’ Bay, the number of cases of atmospheric phenomena was calculated, during which ice accretions of various types could form. As a result, a map of the most common types of ice accretions in the Ob’ Bay region was constructed, which shows that the dominant type of atmospheric icing over the entire territory of the Ob’ Bay region is soft rime. Wet snow occupies from 8 to 30 %. Glaze ice and hard rime are extremely rare. In the cold season, from November to March, soft rime is most often formed, and wet snow accretions in spring and autumn. Based on observational data from 1966 to 2021, trends were estimated in the annual number of meteorological periods during which atmospheric phenomena were observed, potentially leading to hazardous icing. Trends were evaluated using the Mann Kendall test. It is shown that for potentially hazardous cases of atmospheric phenomena causing glaze ice, wet snow and rime accretions, the trends were not significant at the 5 % significance level.