Bridging paleoclimate and seasonal climate prediction: The case of European summer climate

Understanding monthly-to-annual climate variability is essential for improving climate forecast products as well as adapting to future climate extremes. Previous studies show, that European summer climate, including temperature and precipitation extremes, is modulated by hemispheric large-scale circulation patterns, which themselves are connected to Earth system components such as sea surface temperature across temporal scales. Nevertheless, it remains unclear as to how stationary these teleconnections are and if their predictive power is potent across multiple centuries and background climates. By combining d18O isotopes from a European tree ring network with independent paleo-climate reanalyses, we highlight precursors and atmospheric dynamics behind European summer climate over the last 400 years.

We further present evidence that centennial ensemble seasonal climate forecasts capture the causality of the atmospheric
dynamics behind these teleconnections in the 20th century. Our results suggest that tropical sea surface temperature anomalies trigger specific precipitation and diabatic heating patterns which are dynamically connected to extratropical Rossby wave trains and the formation of a circumglobal teleconnection pattern weeks later.