An overview of findings from km-scale simulations of the Destination Earth Climate Adaptation Digital Twin: successes, limitations and future challenges

The Destination Earth Climate Adaptation Digital Twin represents a groundbreaking initiative aimed at achieving operational kilometer-scale global climate simulations for climate adaptation. During Phase 1 (Oct 2022 - Apr 2024), significant technological and scientific advancements have been made, resulting in the production of high-resolution historical (1990-2019, at 10 km) and SP370 scenario (2020-2039, at 5 km) datasets using two state-of-the-art models: IFS-NEMO and ICON.

These high-resolution simulations have demonstrated positive results in capturing extreme precipitation events and provide a realistic representation of the mean climate. The historical simulations outperform the CMIP6 model ensemble across various metrics, as assessed by the Reichler and Kim (2008) Performance Indices. In particular, IFS-NEMO exhibits well-defined precipitation patterns and vertical zonal wind structures, despite a persistent cold temperature bias. Meanwhile, ICON’s simulations - while showing more realistic temperature patterns - are characterized by an overly marked warming rate.

Both ICON and IFS-NEMO biases have been traced to suboptimal initialization strategies and oceanic tuning, both of which are being addressed in preparation for Phase 2. The ongoing efforts aim to refine these models further, enhancing their accuracy and reliability for climate adaptation policies.