The role of atmospheric circulation patterns in driving recent changes in indices of extreme seasonal precipitation acro
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The role of atmospheric circulation patterns in driving recent changes in indices of extreme seasonal precipitation across Arctic Fennoscandia Gareth J. Marshall 1 & Kirsti Jylhä 2 & Sonja Kivinen 3 & Mikko Laapas 2 & Anita Verpe Dyrrdal 4 Received: 18 June 2019 / Accepted: 20 May 2020/ # The Author(s) 2020
Abstract
Extreme precipitation events (EPEs) have a major impact across Arctic Fennoscandia (AF). Here we examine the spatial variability of seasonal 50-year trends in three EPEs across AF for 1968–2017, using daily precipitation data from 46 meteorological stations, and analyse how these are related to contemporaneous changes in the principal atmospheric circulation patterns that impact AF climate. Positive trends in seasonal wet-day precipitation (PRCPTOT) are widespread across AF in all seasons except autumn. Spring (autumn) has the most widespread negative (positive) trends in consecutive dry days (CDD). There is less seasonal dependence for trends in consecutive wet days (CWDs), but the majority of the stations show an increase. Clear seasonal differences in the circulation pattern that exerted most influence on these AF EPE trends exist. In spring, PRCPTOT and CDD are most affected by the Scandinavian pattern at more than half the stations while it also has a marked influence on CWD. The East Atlantic/Western Russia pattern generally has the greatest influence on the most station EPE trends in summer and autumn, yet has no effect during either spring or winter. In winter, the dominant circulation pattern across AF varies more between the different EPEs, with the North Atlantic Oscillation, Polar/Eurasia and East Atlantic patterns all exerting a major influence. There are distinct geographical distributions to the dominant pattern affecting particular EPEs in some seasons, especially winter, while in others there is no discernible spatial relationship. Keywords Fennoscandia . Arctic . Precipitation . Extremes . Climate change . Atmospheric circulation pattern
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10584-02002747-w) contains supplementary material, which is available to authorized users.
* Gareth J. Marshall [email protected] Extended author information available on the last page of the article
Climatic Change
1 Introduction In recent decades, Arctic near-surface air temperatures (SATs) have warmed significantly faster than the global average and, since 1980, have increased more than twice that of the Northern Hemisphere average (Overland et al. 2016). In addition to this anthropogenically forced warming, human activity may be responsible for increased precipitation at northern high latitudes (Min et al. 2008). Indeed, observations and climate model simulations have demonstrated that Arctic precipitation increases in response to Arctic amplification (of SAT) (Anderson et al. 2018) and that both liquid and solid extreme precipitation events (hereinafter EPEs) intensify (O’Gorman 2014, 2015). EPEs are one of the primary triggers of natural hazards in
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