Abstract

Under the rapid and amplified warming of the Arctic, changes in the occurrence of Arctic weather and climate extremes are evident. Here we study extreme cyclone events in the Arctic, which often occur during winter and are associated with extreme warming events that are caused by cyclone-related heat and moisture transport into the Arctic. In that way Arctic extreme cyclones have the potential to retard sea-ice growth in autumn and winter or to initiate an earlier melt-season onset. To get a better understanding of these extreme cyclones and their  occurrences in the Arctic, it is of critical importance to reveal the  related atmospheric teleconnection patterns and understand their  underlying mechanisms. In this study, the methodology of complex  networks is used to identify teleconnections associated with extreme cyclones events (ECE) over Spitzbergen. We have chosen Spitzbergen, representative for the Arctic North Atlantic region which is a hot spot of Arctic climate change showing also significant recent changes in the  occurrence of extreme cyclone events. Complex climate networks have been successfully applied in the analysis of climate teleconnections during the last decade. To analyze time series of unevenly distributed extreme events, event synchronization (ES) networks are appropriate. Using this framework, we analyze the spatial patterns of significant synchronization between extreme cyclone events over the Spitzbergen area and extreme events in sea-level pressure (SLP) in the rest of the Northern hemisphere for the extended winter season from November to March over the time period 1979-2019. The spatial features of the complex network topology are determined and their general relation to storm tracks, jet streams and waveguides is discussed. Link bundles in the maps of statistically significant links of ECEs over Spitzbergen with the rest of the Northern Hemisphere have revealed two classes of teleconnections: Class 1 comprises links from various regions of the Northern hemisphere to Spitzbergen, class 2 comprises links from Spitzbergen to various regions of the Northern hemisphere. For each class three specific teleconnections have been determined. By means of composite analysis, the corresponding atmospheric conditions are characterized.

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