Joint Seminar: Storms and CMIP: investigating km-scale models from an output perspective
Simulating global climate has been a challenge and aspiration ever since the advent of numerical modeling. Today global climate models have become essential tools for understanding the climate system, simulating its behaviour, and informing decision making, particularly in the context of ever increasing climate extremes. In that, models build on a long history of development, from the first attempts to couple atmospheric and ocean models in the late 1960s, to the emergence of Earth system models in the 2000s, to the development of the first km-scale models today.
In the first part of this talk, I show that the latest models provide global climate information with previously unprecedented accuracy, and that next generation km-scale models for the first time even simulate temperature fields indistinguishable from observation-based references. I place this step change in model fidelity in the context of nine observation-based datasets and over 150 global climate models developed over the past three decades since the advent of CMIP. Based on this comparison, I also discuss emerging challenges for model evaluation as the choice of the reference dataset begins to dominate model error for the latest models.
In the second part of the talk, I focus on the representation of climate extremes in km-scale models. Based on their high-resolution output, a range of coarser-resolution datasets are produced by regridding and compared with the original data. I show that for temperature extremes, considerable spatial variability is hidden at coarse resolutions, particularly in mountainous areas, along large rivers, and at coastlines. At coastal land, for example, the maximum temperature is systematically lower by up to 10°C at coarse, CMIP-like resolutions compared to the km-scale. As some of the largest population centers are located on coasts, these findings have important implications for the analysis of climate impacts and related risk assessments.
Datum
15.04.2025
Uhrzeit
15:15–16:15 h
Ort
- Bundesstr. 53, room 022/023
- Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg