CliCCS - Climate, Climatic Change, and Society
A2 - Clouds and Tropical Circulation
The project aims to better understand the tropical heat budget, its link to circulation systems, and how these respond to warming.
The understanding of the system’s sensitivity will be crucial in reducing the epistemic uncertainty in this globally important region – a prerequisite for more tightly constraining global climate sensitivity and hence the range of possible and plausible climate futures. The project will augment and leverage experimental activities in the tropical Atlantic, a new generation of satellites and advances in modeling.
Chairs: Stefan A. Bühler (UHH), Bjorn Stevens (MPI-M)
Team: Felix Ament (UHH), Stefan Bühler (UHH), Theresa Lang (UHH), Elliot McKinnon-Gray (UHH), Ann Kristin Naumann (MPI-M), Jule Radtke (UHH), Bjorn Stevens (MPI-M), Nedjeljka Žagar (UHH)
A6 - Earth System Variability and Predictability in a Changing Climate
How climate variability and predictability will change in a changing climate is only rudimentarily known, and yet this knowledge is crucial for assessing the magnitude of aleatoric uncertainty arising from variability. One critical challenge is the role of the interactions between smallscale and large-scale processes in variability, predictability, and the occurrence of extremes. These three aspects also have strong impacts on social dynamics and human–environment systems. Embedded in an analysis of scale interactions in a global context, the project will focus on key Earth system processes and phenomena, working towards two objectives:
Scale interactions and their impact on variability in a transient climate, with a focus on the variability of the largest ocean heat and carbon sink, the eddy-dominated Southern Ocean;
Changing variability and limited predictability in physical and social contexts, with a focus on the characterization of uncertainties motivated from natural and social sciences.
In both objectives, the investigation of the anatomy of extremes and their potential changes will link the climate-change/large-scale variability to smallscale variability/social impacts. Global climate change simulations will be performed making full use of ICON-ESM’s eddy-resolving oceanic component and convection-permitting atmospheric component, including a full ocean carbon cycle model.
Decadal and seasonal prediction systems with model-native initialization will be used to perform large hindcast simulation ensembles. The project contributes to the overall CLICCS goal by providing the natural-science based understanding of current and expected future climate variability and change, and by performing climate change simulations as a common resource for many CLICCS projects. The assessment of the uncertainty range in the heat and carbon uptake by the ocean is directly relevant to socio-economic studies proposed in Themes B and C.
Chairs: Johanna Baehr, Richard Blender (UHH), Tatiana Ilyina (MPI-M), Jin-Song von Storch (MPI-M), Eduardo Zorita (HZG)
 Zaplotnik Ž., Žagar N., Benedetti A., Semane N., 2020: Inferring atmospheric dynamics from aerosol observations in 4D‐Var. Quarterly journal of the Royal Meteorological Society. DOI: https://doi.org/10.1002/qj.3743
 Lembo V., Lunkeit F., Lucarini V., 2019: TheDiaTo (v1.0) – A new diagnostic tool for water, energy and entropy budgets in climate models. Geoscientific model development. 12, 8, p. 3805-3834 50 p., DOI: https://doi.org/10.5194/gmd-12-3805-2019