Extreme marine heatwaves and cold-spells events in the Southern North Sea: classifications, patterns, and trends

In this study, we examined the long-term spatiotemporal trend of marine heatwaves (MHW) and cold spells (MCS) characteristics in southern North Sea over last four decades (1982-2021). We then estimated difference between their annual mean values possible relationship with large-scale climate modes natural sea surface temperature (SST) atmospheric variability using satellite SST data. The warming rate was 0.33 ± 0.06°C/decade associated an increase MHW frequency (0.85 0.39 events/decade) a decrease MCS (-0.92 0.40 entire period. found distinct characteristics, rapid total days (14.36 8.16 days/decade), whereas showed opposite (-16.54 9.06 days/decade). highest observed two decades, especially 2014 (8 events), 2020 (5 2007 (4 which were also warmest years during study Only (2010 2013) had higher frequency, attributed to strong negative phase Atlantic Oscillation (NAO). Our results show that on scale, both East Pattern (EAP) Multidecadal (AMO) play more important role formation than other teleconnections (e.g., NAO). However, NAO made largest contribution only winter. Strong significant (p < 0.05) positive/negative correlations oceanic temperatures MHW/MCS. This suggests global warming, can expect increase/decrease MHW/MCS occurrences future.