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Abstract:
In this study, we investigate the impact of sea surface temperature variability (SST) in the North Atlantic subpolar gyre (SPG) on atmospheric circulation patterns and the climate at northern latitudes. We use the EC-Earth3 model (T255~80 km) and conduct four sets of ensemble AMIP-type experiments with four different prescribed SST anomalies, each with 10 members and spanning 35 years from 1980 to 2014. The experiments are designed so that the climatic impact of SST variability in SPG can be separated from other global modes of SST variability.Results show that SST anomalies in the SPG directly affect the atmospheric circulation between 30-75°N and cause zonally-oriented wave-like anomalies. Specifically, a warm SST anomaly in the subpolar gyre causes strong low pressure anomalies over the North Atlantic and the North Pacific Oceans, and results in the warming of regions mainly between 45-60°N, and the cooling of regions primarily between 60-75°N. Our findings indicate that temperature anomalies are especially noticeable in northern America. Furthermore, we explore atmospheric teleconnections and extreme events associated with the SPG variability, as well as its indirect effects through synergy with North Atlantic and North Pacific SSTs. The findings highlight the importance of the SPG for atmospheric circulation, teleconnections, regional climate and extremes.
