[M-IS01] ENVIRONMENTAL, SOCIO-ECONOMIC, AND CLIMATIC CHANGES IN NORTHERN EURASIA

[MIS01-P24] Identification and climatological analysis of the Novaya Zemlya bora wind

*Vasilisa Koshkina^1,2、Alexander Gavrikov¹、Mikhail Krinitskiy^1,2、Elena Tiushagina¹、Sergey Gulev¹ (1.Shirshov Institute of Oceanology of the Russian Academy of Sciences、2.Moscow Institute of Physics and Technology (National Research University))

キーワード：Novaya Zemlya bora, downslope windstorms, mesoscale processes, automatic identification of anomalies, Arctic, numerical modeling

The Novaya Zemlya (NZ) archipelago is well-known for its experience of the bora, a mesoscale phenomenon characterized by cold and strong downslope windstorms. These extreme and destructive weather events occur when large-scale air currents encounter mountain barriers. In the NZ region, the bora originates when cold air from the Kara Sea crosses the NZ mountain range and enters the relatively warmer Barents Sea. In this transition, the bora can reach, and even exceed, hurricane strength. Boras are observed in various regions worldwide, including the Croatian and Adriatic Bora, as well as the Mistral in France. Downslope windstorms, such as the bora, pose a serious threat to coastal infrastructure, often resulting in human casualties and significant economic damage. This is particularly important to consider for navigation along the Northern Sea Route, where ships and stations can be affected by icing caused by these windstorms. Most of the research on mesoscale extreme weather events primarily consists of "case studies". These studies involve conducting high-resolution numerical modeling to analyze specific abnormal wind events. Researchers also utilize data from both direct and remote observations for further analysis. However, it is important to note that relying solely on this approach does not provide a comprehensive assessment of the contribution of extreme events to the overall dynamics of the atmosphere or their role in climatological processes. Due to the mesoscale nature of the bora and the limitations in resolution and dynamics within global models, accurately predicting this extreme event remains a significant challenge. Nevertheless, there is a growing interest in the possibility of forecasting bora events in advance. To achieve this, it is crucial to establish general criteria for automatically identifying bora patterns within numerical data. By obtaining statistical information on the occurrence of bora winds in NZ archipelago based on these identification results, researchers can then investigate the conditions, mechanisms, and dynamics involved in the formation and dissipation of the bora. In this study, we utilized a high-resolution (6 km) climatic (2015-2023) run of the WRF model over the NZ region. The primary objective was to develop comprehensive criteria for identifying the Novaya Zemlya bora and gaining a better understanding of the key factors involved in its formation. The identification criteria used in this study aims to differentiate the occurrence of the NZ bora by comparing wind speeds between the Barents and Kara Seas, as well as considering wind direction. By employing these criteria, the study aims to accurately identify “true” bora events while distinguishing them from situations that may have a similar effect but are not actually the bora. Using the outlined approach, the study calculated comprehensive statistics of the bora phenomena over a significant period of time. Subsequently, individual and statistical analyses were conducted on various meteorological parameters. These analyses facilitated the categorization of different types of bora based on their distinct characteristics. Furthermore, these investigations helped identify the factors that influence the mechanisms of bora occurrence. This detailed analysis significantly enhances our understanding of the bora phenomenon and provides a solid foundation for further research and improved forecasting capabilities.