The Design Document page provides a description of the algorithms, implementation and planned testing including unit, verification, validation and performance testing. Please read Step 1.3 Performance Expectations that explains feature documentation requirements from the performance group point of view.

Design Document

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The first table in Design Document gives overview of this document, from this info the Design Documents Overview page is automatically created.

In the overview table below 4.Equ means Equations and Algorithms, 5.Ver means Verification, 6.Perf - Performance, 7. Val - Validation

Equations: Document the equations that are being solved and describe algorithms
Verification Plans: Define tests that will be run to show that implementation is correct and robust. Involve unit tests to cover range of inputs as well as benchmarks.
Performance expectations: Explain the expected performance impact from this development
Validation Plans: Document what process-based, stand-alone component, and coupled model runs will be performed, and with what metrics will be used to assess validity

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In the table below 4.Equ means Equations and Algorithms, 5.Ver means Verification, 6.Perf - Performance, 7. Val - Validation, - competed, - in progress, - not done

Overview table for the owner and an approver of this feature

1.Description	Addition of a MPAS-framework based sea-ice component
2.Owner	Adrian Turner
3.Created	25 Sep 2015
4.Equ
5.Ver
6.Perf
7.Val
8.Approver	Todd Ringler (Unlicensed)
9.Approved Date
V1.0	Accepted

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Table of Contents

Title: MPAS-CICE

Requirements and Design

ACME Ocean-Ice Group

Date: September 25, 2015

Summary

The overarching goal here is the reformulation of CICE into the unstructured MPAS framework. Success is the production of a MPAS-CICE model that is equivalent or better in terms of fidelity than the POP-based CICE model.

Requirements

Requirement: CICE 4.0 column physics

Date last modified:
Contributors: Todd Ringler (Unlicensed), Adrian Turner and Elizabeth Hunke (Unlicensed)

MPAS-CICE is required to utilize column physics that is equivalent or better than CICE 4.0.

Requirement: CICE 4.0 EVP solver

Date last modified:
Contributors: Adrian Turner

MPAS-CICE is required to use a constitutive relation that is equivalent or better than the elastic-viscous-plastic (EVP) solver used in CICE 4.0.

Requirement: CICE 4.0 velocity solver

Date last modified:
Contributors: Adrian Turner

MPAS-CICE is required to use a velocity solver that is equivalent or better than that used in CICE 4.0.

Requirement: CICE 4.0 transport

Date last modified:
Contributors: Adrian Turner

MPAS-CICE is required to use a transport scheme that is equivalent or better than that used in CICE 4.0.

Algorithmic Formulations

Design solution: CICE 4.0 column physics

Date last modified: September 25, 2015
Contributors: Adrian Turner and Elizabeth Hunke (Unlicensed)

CICE 4.0 column physics has been documented outside of ACME. Reference peer-reviewed CICE 4.0 here: reference

Design solution: CICE 4.0 EVP solver

Date last modified: September 25, 2015
Contributors: Adrian Turner

The EVP solver is documented here: reference

Design solution: CICE 4.0 velocity solver

Date last modified: September 25, 2015
Contributors: Adrian Turner

The velocity solver is documented here: reference

Design solution: CICE 4.0 transport

Date last modified: September 25, 2015
Contributors: William Lipscomb (Unlicensed)

CICE 4.0 transport uses incremental remapping. Incremental remapping on a convex polygons is documented here: Lipscomb, W., & Ringler, T. (2005). An incremental remapping transport scheme on a spherical geodesic grid. Monthly Weather Review, 133(8), 2335–2350.

Design and Implementation

Implementation: CICE 4.0 column physics

Date last modified: September 25, 2015
Contributors: Adrian Turner and Elizabeth Hunke (Unlicensed)

Since the column physics is independent of the horizontal grid and discretization, identical source code for the column physics can be used in POP-CICE and MPAS-CICE. The design solution here is to extract the column physics into a "stand-alone" repository and "import" that repository into POP-CICE and MPAS-CICE at build time.

Implementation: CICE 4.0 EVP solver

Date last modified: September 25, 2015
Contributors: Adrian Turner

The EVP solver is independent of horizontal discretization, so its implementation in MPAS-CICE can be identical to its implementation in POP-CICE.

Implementation: CICE 4.0 velocity solver

Date last modified: September 25, 2015
Contributors: Adrian Turner

The velocity solver utilizes a new finite-element discretization for solving the momentum equation including the important divergence of stress tensor term.

Implementation: CICE 4.0 transport

Date last modified: September 25, 2015
Contributors: William Lipscomb (Unlicensed)

The Incremental Remapping (IR) scheme follows closely in concept to that shown in Lipscomb and Ringler (2005) (LR). On notable change is the computation of back-trajectory. In LR, departure areas were obtained by sorting back velocities not the appropriate cell, finding intersections and building areas. Essentially, the LR method was to do all of the "by hand". For this updated implementation of IR, we will use third-party tools to compute departure areas. These tools take any two convex polygons as input and return the area of overlap as output.

Planned Verification and Unit Testing

Verification and Unit Testing: short-desciption-of-testing-here

Date last modified:
Contributors: Adrian Turner

We will configure MPAS-CICE using both quadrilaterals (POP) and convex polygons (MPAS). Both of these configurations will be using "real world" grids of the ocean / sea-ice domain. Since the v1 MPAS-CICE uses most of the same physics/dynamics/parameterizations as POP-CICE, we will verify the code by comparing MPAS-CICE with quads to POP-CICE. Once this level of verification is complete, we will compare MPAS-CICE with convex polygons to MPAS-CICE with quads.

In addition to verifying the full system in the many, each of the components (column physics, EVP, velocity solver and incremental remapping) are verified individually.

Planned Validation Testing

Validation Testing: short-desciption-of-testing-here

Date last modified:
Contributors: Adrian Turner and Elizabeth Hunke (Unlicensed)

Validation of MPAS-CICE will occur through analysis of coupled ocean / sea-ice simulations with CORE II forcing. These simulations will be carried out on each of the meshes target for the ACME coupled simulations and /wiki/spaces/OCNICE/pages/1867925.

Planned Performance Testing

Performance Testing: short-desciption-of-testing-here

Date last modified:
Contributors: Patrick Worley (Unlicensed), Philip Jones, Adrian Turner

Performance evaluation will be carried out concurrently with the validation testing, i.e. using coupled ocean / sea-ice simulations with CORE II forcing.