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Transport of ocean BGC tracers is ~70% of the cost of MPAS-O (when BGC tracers are turned on). We hypothesize that the advection step of the BGC tracer transport can be increased to 2-3 times that of the baroclinic time step with little loss in accuracy, thereby decreasing the overall cost of transport for BGC tracers in the ocean. We propose to implement a tracer-consistent, mass-conserving supercycling of the advection of all passive tracers in MPAS-O. If possible, options to (i) supercycle the tracer advection at time-steps larger than the sea-ice coupling interval (referred to as supercycling-over-coupling [SOC]) and (ii) subcycle the BGC reactions will be included. We propose to validate the scheme in MPAS by testing in a G-case configuration (ocean + ice), comparing mass conservation of carbon within the ocean, and comparing monthly averages of BGC tracer outputs.
Requirements
Requirement:
Date last modified: 08/13/2021
Contributors: Katherine Smith and Andrew Bradley
Algorithmic Formulations
Date last modified: 08/13/2021
Contributors: Andrew Bradley
Design and Implementation
Date last modified: 08/13/2021
Contributors: Andrew Bradley, Katherine Smith, and Mathew Maltrud
Planned Verification and Unit Testing
Verification and Unit Testing:
Date last modified: 08/13/2021
Contributors: Andrew Bradley
Planned Validation Testing
Validation Testing:
Date last modified: 08/13/2021
Contributors: Katherine Smith and Andrew Bradley
Planned Performance Testing
Performance Testing:
Determine performance by running MPAS-O with Supercycling turned on and off.
Date last modified: 08/13/2021
Contributors: Andrew Bradley and Katherine Smith
We will test the performance of the supercycling feature by running a G-case configuration (ocean + sea ice) of MPAS with and without supercycling turned on and compare timers of overall run time between the two. We expect a speed up of the run time with supercycling turned on.