Improving Tide-Estuary Representation in MPAS-Ocean

New project starting Sept 2016.

The proposed project will develop a new tidal and estuary system (TES) component in DOE’s MPAS-Ocean (‘MPAS-O’ hereafter) model to improve its skills in TES and to reduce uncertainties in the coastal biogeochemistry (BGC) simulation. We propose specific changes/additions to the MPAS-O that adapt it to address the challenges as found in TES’s. A major change is the addition of an implicit version of MPAS-O (‘MPAS-OI’) for TES’s, which is coupled to MPAS-O at an offshore boundary with attention being paid to the conservation and smooth transition across the boundary. Other additions include: new turbulence closure schemes, new types of horizontal cells, a new option for momentum advection, a new treatment of bottom boundary condition using a ghost-cell Immersed Boundary Method, a nonlinear higher-order transport solver, new inundation schemes, and optional coupling with a well-tested TES model. For the BGC model development, we will focus on carbon and nutrient cycling in TES’s, and how they affect open-ocean carbon cycle dynamics. Specifically, we will refine the carbon cycle model by considering the effects of sediment resuspension on water-sediment exchange, refine the role of phosphorus cycle, and improve light treatment in TES’s using either an empirical formulation or a light model. The new MPAS-OI and its BGC component will be tested on a few TES’s using both quantitative and process-based error metrics in order to assess the improvement in representing important TES processes, and as an outcome of this project, we expect overall reduction in the errors and uncertainties in the MPAS-O global modeling system.

The proposed project will enhance ACME ‘s (Accelerated Climate Model for Energy) overarching goals and complement the expected version 2 developments by directly addressing two immediate needs in tide-estuary representation and coastal BGC in the global model. The new model fills in a critical knowledge gap in our understanding of the multi-scale processes in the oceans and TES’s, and the simulation outputs will have a large impact on the wider community upon release to the public for analysis. The project is also in line with ACME project’s long-term goal of seeking to include components required to simulate impacts of sea-level change and storm surge on coastal regions.

Project Term: 
2016 to 2019
Project Type: 
Cooperative Agreement (CA)