On the role of the Atlantic Meridional Mode in eastern European temperature variability

The eastern European (EE) region has experienced record-breaking heatwave events in recent years, and such events are expected to increase in future with global warming. Early warning systems are an important step towards mitigating their impacts. Here we seek to further clarify the effect of Atlantic Meridional Mode (AMM) on the EE region temperature variability. Using observations and climate model experiments, we show a significant association between the AMM and temperature variability across the region. The positive phase of AMM leads to a significant increase in EE temperature of 0.9 C, p-value < 0.1, for a one standard deviation AMM anomaly, and vice-versa. The mechanism through which the AMM can modulate the EE temperature arises through a persistent planetary-scale Rossby wave which causes an anomalous anticyclone circulation leading to a positive temperature anomaly. This relationship, along with the mutually exclusive and independent large-scale climatic modes such as the El Nino-Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO), have important implications for improving the prediction of EE heatwaves.

Automated summary

This study reveals a significant association between the Atlantic Meridional Mode (AMM) and temperature variability in the eastern European region. Positive AMM phase leads to a significant increase in temperature, while negative phase has the opposite effect. The AMM modulates the temperature through planetary-scale Rossby waves and anomalous anticyclone circulation.