Extreme cyclone events in the Arctic: Wintertime variability and trends

• Published in: Environmental Research Letters
• Main Authors: Rinke, Annette, Maturilli, Marion, Graham, R M, Matthes, Heidrun, Handorf, Dörthe, Cohen, L, Hudson, S R, Moore, J C
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2017
• Subjects: Arctic; North Atlantic; Ny Ålesund; Ny-Ålesund; Sea ice
• Online Access: https://epic.awi.de/id/eprint/46450/; https://doi.org/10.1088/1748-9326/aa7def; https://hdl.handle.net/10013/epic.fb4e6c78-428b-463a-8387-94688d6d312f

Typically 20–40 extreme cyclone events (sometimes called ‘weather bombs’) occur in the Arctic North Atlantic per winter season, with an increasing trend of 6 events/decade over 1979–2015, according to 6 hourly station data from Ny-Ålesund. This increased frequency of extreme cyclones is consistent with observed significant winter warming, indicating that the meridional heat and moisture transport they bring is a factor in rising temperatures in the region. The winter trend in extreme cyclones is dominated by a positive monthly trend of about 3–4 events/decade in November–December, due mainly to an increasing persistence of extreme cyclone events. A negative trend in January opposes this, while there is no significant trend in February. We relate the regional patterns of the trend in extreme cyclones to anomalously low sea-ice conditions in recent years, together with associated large-scale atmospheric circulation changes such as ‘blocking-like’ circulation patterns (e.g. Scandinavian blocking in December and Ural blocking during January–February).