Hauke Schmidt

Throughout my career I’ve developed and applied numerical models to better understand processes in the atmosphere and climate system. Currently, I’m particularly interested in the question how circulation affects Earth’s climate response to forcings, and finally its equilibrium climate sensitivity (ECS). ECS is defined as its surface temperature response to a doubling of the atmospheric CO₂ concentration. According to the IPCC’s Sixth Assessment Report from 2021 Earth’s the value ECS lies “likely” between 2.5°C and 4°C, a range that I think is still embarassingly large. Climate models can be used to better understand processes that have an influence on it.

Within the “Global Circulation and Climate” group that I’m heading we are working more broadly on issues related to circulation and climate sensitivity, like atmospheric temperature and moisture, specifically in the tropical upper troposphere, or pattern effects. Our main tool to study these topics is a hierarchy of models from the very idealized one-dimensional radiative-convective-equilibrium model “konrad” to the storm-resolving ICON-Sapphire general circulation model. The “Global Circulation and Climate” group was instrumental in the development of the former and contributes to the development of the latter. Recently, we have, e.g., analyzed how results of ICON-Sapphire, which resolves the atmosphere horizontally with a grid-spacing of a few kilometers, are affected by strongly refining the vertical grid.

Other topics I have been working on during my career include:

• Interactions of dynamics, chemistry and radiation in the middle and upper atmosphere
• Effects of solar variability on the Earth system
• Vertical coupling processes in the atmosphere
• Implications of climate engineering schemes to limit climate change
• Adjoint modeling
• Air pollution modeling