Long-term climate simulation in NorESM: burst-coupling the sediment in the BLOM/iHAMOCC ocean module

TL;DR

This paper introduces a burst coupling method for long-term climate simulations in NorESM, enabling sediment-ocean interactions to reach steady state efficiently for paleo-climate studies.

Contribution

The paper presents a novel burst coupling approach that significantly reduces computational time for long-term climate simulations involving sediment and ocean interactions.

Findings

Sediment reaches steady state after 50,000 years of simulation.

Burst coupling reduces simulation time to about one week.

Method applicable for paleo-climate and present-day studies.

Abstract

In this report we set forth a simulation method for long-term simulations of NorESM, the Norwegian Earth System Model. In this the sediment is repeatedly decoupled and coupled to the ocean model (BLOM/iHAMOCC), a process called burst coupling. Through this, the ocean (seawater and sediment) is brought into an approximate steady state. We show that just the model has to run at least 50000 yr to get in an approximate steady state. With burst coupling this can be done in a computationally reasonable time (wall time in the order of one week). The method can be used to generate the sediment over hundreds of thousands of years, so it is useful not only for present-day simulations but also for paleo-climatological studies.