CMCC Seminars in Bologna

CMCC Seminar
26 January 2024, 10.00 am CEST


Title: Kilometer-Resolution Ocean and Sea Ice Modeling at Tsinghua University – Progress and Outlook
Speaker: Prof. Shiming Xu
Department of Earth System Science (DESS), Tsinghua University

We report status-quo of ocean/sea-ice and coupled modeling activities carried out at Tsinghua University over high-performance computers, including the new Sunway supercomputer with over 40 million cores. Based on the coupled framework of Community Earth System Model (CESM, version 2.2), we construct a hierarchy of model resolutions, with the highest resolution at 2.4km for the ocean/sea ice components. Specifically, we introduce the results of submesoscale-capable simulations of the global ocean, as well as the modeling efforts over sea ice kinematics. Both scaling analysis and modern diagnostics of Linear Kinematic Features are carried out for the simulated sea ice deformations, with sensitivity studies over the resolution and the rheology model. Besides, efficient parallelization enables climate-ready simulations at the spend of over 200 simulated days per day (SPDP) for the coupled run. For the model developments in the long run, the talk will also introduce OMARE (Ocean Model with Adaptive REsolution), which is a prototype ocean model capable of flexible simulation of the multi-scale ocean processes and the highest resolution at 400m.


26 January 2024, 11.00 am CEST

Title: Impacts and state-dependence of AMOC weakening in a warming climate
Speaker: Katinka Bellomo
Department of Environment, Land and Infrastructure Engineering, Polytechnic University of Turin

“In this seminar, I will explore recent advancements in our understanding of the ocean’s role in the climate system, with a particular focus on the Atlantic Meridional Overturning Circulation (AMOC) and its implications for future climate change. Climate models project a decline in AMOC strength due to increased ocean stratification, but its relative impact compared to greenhouse gas-induced changes remains unclear. I will describe our recent work addressing this issue, in which we have both examined climate model simulations in the Coupled Model Intercomparison Project (CMIP) archive, and also carried out idealized targeted experiments with a state-of-the-art global climate model (EC-Earth3). Specifically, using EC-Earth3 we compare an abrupt 4xCO2 simulation with an identical one, except we artificially fix the AMOC strength at preindustrial levels. With this design, we can formally attribute differences in climate change impacts between these two experiments to the AMOC decline. In addition, we quantify the state-dependence of AMOC impacts by comparing the aforementioned experiments with a preindustrial simulation in which we artificially reduce the AMOC strength using the more classical “water hosing” approach.  Finally, we interpret these results in the context of existing CMIP simulations. We find that an AMOC decline leads to mean climate changes, including global cooling, widespread drying in the Northern Hemisphere and a southward shift of the ITCZ. We also find an increased frequency of wintertime NAO+ and more extreme precipitation events in northwestern Europe, despite the overall drying. However, our findings demonstrate that AMOC decline impacts are state-dependent, thus understanding AMOC impacts on future climate change requires targeted model experiments. Join me as we delve into the intricate coupling between the Atlantic Ocean and the atmosphere, which influences the jet-stream, weather patterns, and precipitation, and discover the crucial role of the ocean in our evolving climate.”


BIO: Dr. Katinka Bellomo is a climate scientist at Politecnico di Torino’s Department of Environment, Land, and Infrastructure Engineering, and specializes in unraveling the intricate connections between air and sea in shaping climate variability and change. Employing a blend of numerical models, theory, and observations, she investigates mechanisms that drive large-scale atmospheric impacts on regional weather patterns. Holding a Ph.D. in Meteorology and Physical Oceanography from the University of Miami (2015), Dr. Bellomo previously conducted postdoctoral research at Columbia University and the Italian National Research Council, cultivating a deep understanding of climate dynamics.

Both seminars will be held in CMCC Bologna meeting room (second floor), viale Berti Pichat 6/2.

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