Parameterizing Eddy Transport of Biogeochemical Tracers
Abstract
The distribution of oceanic biogeochemical tracers is fundamentally tied to physical dynamics at and below the mesoscale. Since global climate models rarely resolve those scales, turbulent transport is parameterized in terms of the large‐scale gradients in the mean tracer distribution and the physical fields. Here, we demonstrate that this form of the eddy flux is not necessarily appropriate for reactive tracers, such as nutrients and phytoplankton. In an idealized nutrient‐phytoplankton system, we show that the eddy flux of one tracer should depend on the gradients of itself and the other. For certain parameter regimes, incorporating cross‐diffusion can significantly improve the representation of both phytoplankton and nutrient eddy fluxes. We also show that the efficacy of eddy diffusion parameterizations requires timescale separation between the flow and reactions. This result has ramifications for parameterizing subgrid scale biogeochemistry in more complex ocean models since many biological processes have comparable timescales to submesoscale motions.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 28, 2021
- Source ID
- 10.1029/2021gl094405
Entities
People
- Alexis K. Kaminski
- Channing J. Prend
- Glenn R. Flierl
- Katherine M. Smith
Organizations
- Horizon 2020
- Los Alamos National Laboratory
- Massachusetts Institute of Technology
- National Science Foundation
- Office of Naval Research
- University of California, San Diego