Die intrinsische Vorhersagbarkeit der Atmosphäre

The predictability of the atmosphere is crucial for weather forecasting as it sets the boundaries of what we can predict. This article examines the predictability of the atmosphere through identical twin experiments with a numerical weather prediction model. The evolution of forecast error is investigated from convective to global scales by conducting simulations on a grid with a resolution of 4 km. It was determined that error growth corresponds to Edward Lorenz’s concept of finite predictability limit of the atmosphere, regardless of the initial error size. Our estimates indicate that the average global predictability is about 2–3 weeks. Additionally, we found that predictability in the tropics is longer (more than 20 days) compared to mid-latitudes and polar regions (just over 2 weeks). Each climatic zone exhibited different patterns in error growth, consistent with its underlying dynamics.