Meeting Documents

Scale-Dependent Drivers of Air-Sea CO₂ Flux Variability Using the ECCO-Darwin Model

Abstract

In climate studies, it is of great interest to separate changes driven by natural modes inherent to the system of interest as opposed to changes due to external forcings. Here we design and run a suite of in-silico experiments that separate the impact of the atmospheric growth rate and variable climate on the ocean carbon sink. In this study, we utilize a single ocean biogeochemistry model (ECCO-Darwin) to quantify the relative importance of forcing from: 1) the variable atmospheric pCO₂ growth rate and 2) internal climate variability. This work has a goal of disentangling the space-time variability of the dominant drivers. Our results show that when globally integrated, the variable atmospheric pCO₂ growth rate and climate exhibit similar magnitude impacts on ocean carbon uptake but locally, the variability in CO₂ flux, specifically interannual variability, is dominated by climate. The implications of this experiment for real-world observing systems are clear: in order to detect changes in the ocean sink due to slowing atmospheric pCO₂ growth rates, which we hope to observe in coming decades due to mitigation of anthropogenic emissions, better observing systems and constraints on climate-driven ocean variability will be required.