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
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
Title: SNICAR-AD Shortwave Radiation for Sea Ice
Requirements and Design
E3SM Cryosphere Group
Date:
Summary
Requirements
Modify the sea-ice shortwave code to include a new subroutine SNICAR_AD that
- provides new input files for snow and ice optics adopted by ELM;
- expands the shortwave radiative calculation to 5 subdivided solar bands adopted by ELM;
- removes empirical adjustment for radiative-effective snow grain size;
- adopts a new algorithm to correct for the bias of near-infrared albedo and absorption when solar zenith angles are larger than 75 degrees.
Date last modified: Jun 1st, 2019
Contributors: Cheng Dang (Unlicensed)
Algorithmic Formulations
Design solution: described in the following article
Dang, C., Zender, C. S., and Flanner, M. G.: Inter-comparison and improvement of 2-stream shortwave radiative transfer models for a unified treatment of cryospheric surfaces in ESMs, The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-22, in review, 2019.
Date last modified: July 1st, 2019
Contributors: Cheng Dang (Unlicensed)
Design and Implementation
Implementation:
In ice_shortwace.F90, we added a new subroutine SNICAR_AD to compute the shortwave radiative properties of snow-covered sea ice, which can be turned on by setting config_use_snicar_ad to true.
Pseudo code:
if snow-covered sea ice:
if (SNICAR_AD):
Date last modified: July 1st, 2019
Contributors: Cheng Dang (Unlicensed)
Planned Verification and Unit Testing
Verification and Unit Testing: short-desciption-of-testing-here
Date last modified:
Contributors: (add your name to this list if it does not appear)
How will XXX be tested? i.e. how will be we know when we have met requirement XXX. Will these unit tests be included in the ongoing going forward?
Planned Validation Testing
Validation Testing: short-desciption-of-testing-here
Date last modified:
Contributors: (add your name to this list if it does not appear)
How will XXX be tested? What observational or other dataset will be used? i.e. how will be we know when we have met requirement XXX. Will these unit tests be included in the ongoing going forward?
Planned Performance Testing
Performance Testing: short-desciption-of-testing-here
Date last modified:
Contributors: (add your name to this list if it does not appear)
The new implementation is not expected to have a significant impact on the computational cost/performance of E3SM.