TRR181 Energy Transfers in Atmosphere and Ocean: M3 - Towards Consistent Subgrid Momentum Closures
ACRONYM
TRR181/M3
Title
TRR181 Energy Transfers in Atmosphere and Ocean: M3 - Towards Consistent Subgrid Momentum Closures
General information
Computational models of atmosphere and ocean can only resolve a limited range of scales. Dynamical processes on scales smaller than the grid scale are parameterized or simply truncated.
When the grid scale lies within one of the classical turbulent inertial ranges, the use of viscous closures is well-understood, but in practice, simulations tend to be over-dissipative because of insufficient scale separation between numerical dissipation and the forcing scale. This problem is particularly severe when forcing occurs near the grid scale, for example through the process of baroclinic instability which converts available potential energy into kinetic energy in eddy-permitting or barely eddy-resolving simulations of the ocean. In general, momentum closures, as well as momentum advection, must aim at being minimally dissipative, which may require active reinjection of energy into the resolved kinetic energy range, a process termed in the context of oceanic momentum closures as kinetic energy backscatter.
This project will evaluate existing closure and advection schemes and develop new ones with a particular focus on (i) properly analysing their precise discrete behaviour, especially the energy budget near the resolution scale and the propagation of linear waves on unstructured meshes, (ii) developing closures that work on unstructured and variable grids (the B-grid in FESOM, the hexagonal and triangular C-grids in ICON-IAP and ICON-o), (iii) gaining physical understanding of numerically induced processes, and (iv) developing and assessing stochastic closures.
We will, first, continue the development of ocean kinetic energy backscatter which, as we demonstrated in the first project phase, is an effective means of improving energy consistency of eddy-permitting or barely eddy-resolving ocean simulations. Second, we will investigate the behaviour of models near the grid scale (i) top-down, by analysing the effective resolution of different choices of grids, discrete operators, and momentum closures empirically in the context of realistic model runs, and (ii) bottom-up, by building physical and mathematical understanding of the explicit as well as implicit choices of momentum closures. The combination of these methods and the application to the two different main models of the TRR181 鈥� i.e., FESOM and ICON 鈥� will ensure a holistic approach to the development of efficient, energetically consistent and optimal discretizations of the momentum equations.
Start
June, 2016
End
June, 2028
Funding (total)
-
Funding (黑料视频)
252000
Funding body / Programme
-
DFG
/
Coordination
Centrum f眉r Erdsystemforschung und Nachhaltigkeit (CEN), Germany
Contact
Partners
Alfred Wegener Institute for Polar and Marine Research (AWI), Germany
Catholic University of Eichst盲tt-Ingolstadt, Germany
Catholic University of Eichst盲tt-Ingolstadt, Germany
