Central-European sunshine hours, relationship with the Atlantic Multidecadal Oscillation, and forecast.

Sunshine hours (SSH) is an important meteorological parameter, loosely linked to temperature and precipitation, and highly relevant for various sectors such as agriculture or solar energy. Previous studies have already identified a correlation of European SSH with the thermal state of the North Atlantic. This paper investigates this relationship further by studying annual and monthly SSH of seven long-term Central European SSH series and comparing them to the Atlantic Multidecadal Oscillation (AMO) using Fourier Transformation, Monte Carlo simulation and non-linear optimization. The Fourier spectra of our annual SSH series have their strongest and highly significant peaks in the known AMO period of ~ 50 to ~ 80 years, supporting the hypothesis that European SSH and the AMO are linked. The optimized sinusoids of the seven SSH and the AMO series with these periods show substantial correlations with the corresponding data (r = 0.42-0.55 for SSH and 0.71 for the AMO). Extrapolating the sinusoids, we project a gradual decline in SSH across Central Europe by 9-16% from its current maximum over the next three decades, particularly pronounced in northern regions.