search

ACCESS-NRI / dev_coupling

0 stars 0 forks source link

UM -> CICE flux energy conservation #24

Closed kieranricardo closed 2 months ago

kieranricardo commented 6 months ago

Currently the atm->ice mapping (almost) follows CM2:

  1. CICE exports ice fractions to UM (fraction of non-land area covered by sea ice) with first order conservative remapping (
  2. UM: divide fluxes (averaged over non-land area) by ice area fraction (local ice fluxes)3.
  3. First order conservative remapping to CICE grid

This almost conserves energy, but does not take into account changes in the ice fraction over subsequent CICE time steps.

TODO: scale fluxes by initial ice area / current ice area to maintain energy conservation. This has caused numerical instabilities in the past - revisit in the future when things are more stable.

kieranricardo commented 2 months ago

Solved by limiting ice and snow thickness, model is now stable enough to scale fluxes by initial ice area / current ice area