A11 COSP Design Document

Owned by Tanya Reshel
Last updated: May 29, 2019 by Renata McCoy
3 min read

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 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

Use the symbols below (copy and paste) to indicate if the section is in progress or done or not started.

In the table below, 4.Equ means Equations and Algorithms, 5.Ver means Verification, 6.Perf - Performance, 7. Val - Validation,   (tick) - completed, (warning) - in progress, (error) - not done



Overview table for the owner and an approver of this feature

1.Description

COSP
2.Owner
Yuying Zhang, Po-Lun Ma
3.Created
 
4.Equ
(tick)
5.Ver
(tick)
6.Perf
(tick)
7.Val
(tick)
8.Approver
Shaocheng Xie
9.Approved Date
 
V1.0Accepted
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Table of Contents

Title: Improvements to Satellite Simulators

Requirements and Design

ACME Atmosphere Group

Date: Sep 11, 2015

Summary

The purpose of this task is to improve the capability of the satellite simulators to facilitate an "apple-to-apple" comparison of modeled clouds with satellite observations. COSP  implement the new COSP code to the ACME model. This work includes upgrading the COSP code for improving its computational efficiency and adding Calipso cloud phase diagnostics.

Requirements


Date last modified: Sep 11, 2015 
Contributors: Yuying Zhang

  1. replace COSP version1.3 using COSP version1.4 in the ACME model
  2. modify the interface code
  3. add radiatively active snow in all simulators with fixed lidar snow treatment error

Algorithmic Formulations

Design solution: reference

Date last modified: Sep 11, 2015
Contributors: Yuying Zhang


A. Bodas-Salcedo, M. J. Webb, S. Bony, H. Chepfer, J.-L. Dufresne, S. A. Klein, Y. Zhang, R. Marchand, J. M. Haynes, R. Pincus, V. O. John, 2011: COSP: satellite simulation software for model assessment. BAMS.  http://journals.ametsoc.org/doi/pdf/10.1175/2011BAMS2856.1

J. E. Kay, B. R. Hillman, S. A. Klein, Y. Zhang, B. Medeiros, R. Pincus, A. Gettelman, B. Eaton, J. Boyle, R. Marchand, and T. P. Ackerman, 2012: Exposing Global Cloud Biases in the Community Atmosphere Model (CAM) Using Satellite Observations and Their Corresponding Instrument Simulators. J. Climate, 25, 5190–5207.
doi: http://dx.doi.org/10.1175/JCLI-D-11-00469.1

Design and Implementation

Date last modified: Sep 11, 2015
Contributors: Yuying Zhang


  1. Start from the ACME model in the "master" branch
  2. Made the changes according to the interface code for the COSP1.4 implementation in CAM (bug identified version cam5_3_88)
  3. Fixed the bug identified by Po-Lun Ma for the assignment of convective ice mixing ratio
  4. Replaced the old COSP code with the new version and added the radiatively active snow in all simulators
  5. After the test, push the COSP branch to the GitHub server. Set the pull request and ask for the integrator to merge the changes to the master.


Planned Verification and Unit Testing 

Date last modified: Oct 5, 2015
Contributors: Yuying Zhang


COSP v1.4 will be compared to COSP v1.3 for all simulators. For those simulators that are not changed, they should yield the same results. For those simulators that are upgraded, the yielded differences will be analyzed to make sure that they are from the expected changes in these simulator codes.

Planned Validation Testing 

Date last modified: Oct 5, 2015
Contributors: Yuying Zhang


The output from the original model with COSP v1.3 and the modified model with the COSP1.4 upgrade are examined.

  • The output from the ISCCP/MISR/Calipso simulators are exactly the same as before.
  • The output from the Radar/MODIS simulators have slight differences that come from the changes in these simulator codes from COSP1.3 to COSP1.4.

Some selected comparisons are shown in COSPinACME.pptx


Planned Performance Testing 

Date last modified: Oct 5, 2015
Contributors: Yuying Zhang


The new COSP code has been restructured to greatly improve computational efficiency (particularly for the CloudSat simulator) and Calipso cloud phase diagnostics will be output. An offline run of COSP shows ~30% reduction in computational costs. The performance test still needs to be done with inline running COSP with ACME by working on with the performance team.