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
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Title: ...
Requirements and Design
E3SM CBGC Group
Date: 10/12/2020
Summary
In v1 of E3SM, Hailong Wang led a development feature (A13) which made compatible the treatment of light-absorbing particles deposited in snow and sea ice with the atmospheric MAM aerosol scheme. This feature was accepted into v1.0 on October 2015 and used successfully in the land snow model. However, the feature was never validated in MPAS-SI and so not activated in the v1 simulations. We propose to validate the scheme in MPAS-SI by testing the code in fully coupled mode, comparing mass ratios of black carbon and dust in sea ice with observations, and contrasting the impact of aerosol inclusions on sea ice and snow volume with CESM.
Requirements
Requirement: Analysis of fully coupled simulations with appropriate flags activated and de-activated
- The current v2 code has a dust and black carbon capability already implemented in MPAS-SI. To validate this capability, we require a fully coupled run of at least 30 years with black carbon, dust and radiative feedbacks activated in MPAS-SI namelist.MAM atmospheric aerosols are default in the current codebase.
- We also require a control run. This will be obtained from the v2 WC spin-up.
- Validate black carbon mass ratios with Doherty et al (JGR, 2015) in Arctic sea ice.
- Compare changes in sea ice volume, snow thickness, and ice extent with Holland et al 2012 (Journal of Climate)
- Some parameter tuning will likely be needed.
Date last modified: 10/13/2020
Contributors: Nicole Jeffery
Algorithmic Formulations
None. Code implementation was completed in v1, A13 Interactions With Surface Models - Aerosol Interactions with Ice Design Document
Date last modified:
Contributors: Nicole Jeffery
Design and Implementation
None. See A13 Interactions With Surface Models - Aerosol Interactions with Ice Design Document
Date last modified:
Contributors: Nicole Jeffery
Planned Verification and Unit Testing
Verification and Unit Testing: restartability and parallelism
MPAS-SI already has regression, restartability and parallelism tests for aerosols in the testsuites (testsuite.aerosol_shortwave.xml) . These are tested currently in MPAS-SI with each new PR. Ocean-sea ice simulations with constant atmospheric aerosol fluxes were completed and tested for restartability, parallelism, and stability during v1 development.
Date last modified:
Contributors: Nicole Jeffery
Planned Validation Testing
Validation Testing: Comparison of fully coupled run with models and literature
Date last modified:10/13/2020
Contributors: Nicole Jeffery
In order to validate dynamic and seasonally varying aerosol fluxes on sea ice, we will use a 30 year fully coupled control 30 from the v2 WC spin-up and a 30 year fully coupled simulation with two black carbon tracer groups, four dust groups in the modal aerosol configuration with radiative feed-backs in MPAS-SI. We expect only minor impact in the Southern Ocean and so focus validation on Arctic sea ice. Results will be compared with the following sources.
For black carbon mass ratios in Arctic sea ice:
Doherty, S. J., Steele, M., Rigor, I., and Warren, S. G. (2015), Interannual variations of light‐absorbing particles in snow on Arctic sea ice, J. Geophys. Res. Atmos., 120, 11,391– 11,400, doi:10.1002/2015JD024018.
For climate impacts of aerosols in Arctic sea ice:
Holland, M. M., D. A. Bailey, B. P. Briegleb, B. Light, and E. Hunke, 2012: Improved Sea Ice Shortwave Radiation Physics in CCSM4: The Impact of Melt Ponds and Aerosols on Arctic Sea Ice. J. Climate, 25, 1413–1430, https://doi.org/10.1175/JCLI-D-11-00078.1.
Planned Performance Testing
Performance Testing: short-desciption-of-testing-here
Date last modified:10/13/2020
Contributors: Nicole Jeffery
We'll use the same fully coupled run to contrast computational expense. It is expected that additional aerosols in sea ice snow and ice layers will increase computational cost. If prohibitive, we would consider reducing the cost by testing the impact of reduced set of dust/BC tracers.
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