Variability and predictability of the ocean carbon uptake
Dr. Hongmei Li
Max-Planck Institute for Meteorology, Germany
The world oceans absorb a large portion of the anthropogenic carbon emissions, hence play a crucial role in modulating global carbon cycle and climate change. The ocean carbon uptake shows pronounced decadal variations, which are driven by the internal variability of the earth system. The MPI-ESM grand ensemble produces both positive (i.e., stronger uptake) and negative (i.e., weaker uptake) decadal trends in the ocean carbon uptake in agreement with observations. Negative decadal trends are also projected to occur in the future. The evolution of ocean carbon uptake varies with the initial states. Decadal predictions aim to capture the multi-year variability via improving the initial states of the Earth System. By using a decadal prediction system based on the MPI-ESM, we explore skills in predicting decadal variations of the ocean carbon uptake and investigate origins of the predictability. Prominent potential predictability of ocean carbon uptake is found in most ocean regions, which suggests a potential for establishing predictive skills of ocean carbon uptake against observations. Regionally, e.g. in the North Atlantic western subpolar gyre region, a potential predictive skill of up to 4-7 years and also an evidence from observations is found due to the improvement of ocean physical states.