Description: The research topic of ROADMAPsurstat is the role of the ocean surface state and atmosphere-ocean interactions for climate variability and future projections of impact-relevant weather and climate extreme events.
The general scientific aim of ROADMAP it to deepen our understanding of how the northern hemisphere ocean surface state and ocean dynamics influence the extratropical atmospheric circulation, as well as associated impact-relevant weather and climate extremes across time scales under both present day and future climate conditions.
Within the framework of ROADMAPsurstat GEOMAR is leading work package 4 which is dedicated to investigate the role of the Northern Hemisphere ocean surface state (SST and sea ice) for driving impact-relevant atmospheric extremes, such as atmospheric and marine heat waves and droughts, including compound weather extremes and Mediterranean mesoscale cyclones. Both are large-scale natural variability modes and also climate-change induced anomalies will be considered.
Additionally, GEOMAR will contribute to work package 1 and 3. The focus of work package 1 is the impact of the ocean circulation, especially the Atlantic Meridional Overturning Circulation, on large-scale sea surface temperature (SST) patterns. This work package it therefore closely linked to work package 4. The underlying research question for work package 3 are: How and on which time scales do extratropical ocean-atmosphere interactions control the tropospheric eddy-driven jets, cyclone variability (storm track), blocking events and the associated dynamical link to extreme conditions; and also how such controls can be modified by global warming.
Targeted at work package 1, dedicated sensitivity experiments will be conducted, with a global coupled climate model where the ocean model has an eddy-resolving nest (1/10°) over the North Atlantic. For work package 3, GEOMAR will contribute pacemaker experiments, where the variability of the Atlantic or Pacific Ocean is close to that found in observation using SST wind stress forcing in a partially coupled mode. For work package 4, high-resolution OpenIFS atmosphere-only simulations with varying surface input and coupled FOCI-OpenIFS experiments with eddy-resolving resolution in the North Atlantic are used to determine the effect of oceanic anomaly patterns for atmospheric extreme events. High frequency in-situ data will also be used for a more accurate analysis of the extremes.

Project period: 01.06.2020 - 31.05.2023
Funding agency: BMBF
Coordination: GEOMAR
Contact: Prof. Dr. Joakim Kjellsson

Description: The Southern Ocean regulates the global climate by controlling heat and carbon exchanges between the atmosphere and the ocean. Rates of climate change on decadal time scales ultimately depend on oceanic processes taking place in the Southern Ocean, yet too little is known about the underlying processes. Limitations come both from the lack of observations in this extreme environment and its inherent sensitivity to intermittent small-scale processes that are not captured in current Earth system models. To contribute to reducing uncertainties in climate change predictions, the overall objective of SO-CHIC is to understand and quantify variability of heat and carbon budgets in the Southern Ocean through an investigation of the key processes controlling exchanges between the atmosphere, ocean and sea ice using a combination of observational and modelling approaches.
 
Project period: 01.11.2019 - 31.10.2024
Funding agency: EU / H2020
Coordination: Sorbonne University, France
Contact: Joakim Kjellsson
Project Website