The role of atmospheric circulation patterns in driving recent changes in indices of extreme seasonal precipitation across Arctic Fennoscandia

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.

Analysis of Spatiotemporal Variability in Extreme Climate and Potential Driving Factors on the Yunnan Plateau (Southwest China) during 1960–2019

“…This also explains the correlation between the continuous drought in winter and spring in Yunnan and the ENSO oscillation period. The correlation between ENSO and TXn east of 103 • E is positive, ENSO and TXn west of is negative; this can be attributed to the interannual variation of ENSO on the decrease in cloud cover caused by the gradual decrease in monsoon precipitation from coastal to inland [63].…”

“…Abnormal development of atmospheric circulation patterns often leads to abnormal weather phenomena [63]. In Yunnan, atmospheric circulation patterns (ENSO, AO, and NAO) extreme temperature is more significant than its influence on extreme precipitation [64].…”

The role of teleconnection patterns in the variability and trends of growing season indices across Europe

“…Linking the variability in climate indices to teleconnection patterns can also help us to understand how various aspects of the climate are changing in response to changes in atmospheric circulation. There have been several studies linking indices to teleconnection patterns in parts of Europe, such as temperature and precipitation indices in Serbia (Kneževi c et al, 2014;Arsenovi c et al, 2015), extreme precipitation in Finland (Irannezhad et al, 2017) and seasonal precipitation in northern Scandinavia (Marshall et al, 2020). These studies have tended to focus on particular countries or regions rather than all of Europe, but the release of the INDECIS dataset (Dominguez-Castro et al, 2020) has facilitated the study of climate indices on the pan-European scale and the role of teleconnection patterns in their trends and variability.…”

Natural Hazards and Extreme Events in the Baltic Sea region

“…Other studies (e.g., Deser et al, 2017;Marshall et al, 2020) do not find a significant trend. It has been speculated that these changes are due to a shift of the Atlantic Multidecadal Variability (AMO) into the warm phase (Gastineau and Frankignoul, 2015).…”