The BCCR FTI project

Background/Motivation:

Equilibrium Climate Sensitivity (ECS) is an uncertain factor that integrates the various processes in the climate system into one policy relevant number, e.g., 1.5 C warming given certain CO emission.
A significant source of uncertainty in model-based estimates of climate sensitivity is associated with ocean heat content (OHC) and how that will increase as the stratification changes under global warming.
- Depends on both local ocean processes and ocean-atmosphere coupling biases
To reduce the uncertainty, we test a partial coupling method, which can be used in modern and paleo context to derive self-consistent estimates of ECS and OHC.
The approach:
- first takes the observed SST into a slab ocean
- then couples an atmospheric model with the slab ocean model to derive an atmospheric state that is in balance with the given SST field. The simulated local air-sea surface fluxes are recorded over a climatic period
- the air-sea fluxes are used to drive an ocean general circulation model towards equilibrium.
Potential benifits:
- this method is self-consistent, conserves heat, and avoids coupled biases and related feedbacks.
The objective:
- To test how far from the original SSTs will the forced ocean model drift due to circulation biases,

net hflx (to ocean) with salinity relaxation	hflx with minus w/o salinity relaxation

net freshwater budget	evaporation difference

Model framework for consistent estimation of climate sensitivity and ocean heat content

Slab ocean setup descriptions