资源环境科技发展态势分析平台

The Arctic has experienced step changes in climate conditions, which are still not fully understood. Particularly intriguing was the Early Twentieth-Century Arctic Warming (ETCAW), which occurred prior to anthropogenic interference in the environment. This paper quantitatively assesses the differences in atmospheric circulation patterns during periods of warming and cooling on Spitsbergen with a particular focus on ETCAW. The patterns of atmospheric circulation were taken from the catalog of day-by-day circulation types created for Svalbard. The catalog includes 21 circulation types, assigned to every day between 1920 and 2017. The research focused on winter and autumn, the seasons exhibiting pronounced ETCAW on Spitsbergen. The long-term variability in autumn and winter air temperatures on Spitsbergen significantly depends on the frequency of air advection from clearly defined directions and reveals some seasonal differentiation. Warming was related in autumn to southern and south-eastern advection, in winter to southern advection, and in both cyclonic and anticyclonic conditions. These warm types explained up to 21% (September-November) or 25% (December-February) of the variability in air temperature. In winter, cooling was significantly related to anticyclonic type with air advection from the northeast (NEa: 24% of variability): in autumn to cyclonic northern (Nc) and northeastern (NEc) types. During ETCAW, the frequency of warm circulation types was significantly higher, and that of cold circulation types significantly lower. No relevant differences in patterns were found between ETCAW and Recent Arctic Warming; however, the frequency of warm and cold types was higher and lower, respectively, during ETCAW.