A Synthetic Ensemble for Air-Sea CO2 Flux Observations
The external and internal components of variability in air-sea CO2 flux can be separated within large initial condition ensembles of Earth system model simulations. In these ensembles, the ensemble mean describes the externally forced variability, while the departures from the ensemble mean represent the internal component of variability. But how can one tease apart the contributions of internal and external processes to variability in real-world observations, for which we have only one realization or "ensemble member?"
Here, we statistically resample the observational record in order to generate a synthetic ensemble of air-sea CO2 flux. In the resulting observational large ensemble, each ensemble member has statistical properties that are similar to the observational record, but with a unique sequence of internal variability and an identical externally forced signal. We use this observational large ensemble to explore the origin of variability in the observation-based air-sea CO2 flux.