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Overview table for the owner and an approver of this feature

1.Description

Ozone (O3v2) with tropospheric loss in the lowermost a few layers 
2.OwnerQi Tang
3.Created
4.Equ(tick)
5.Ver(tick)
6.Perf(error)
7.Val(warning)
8.Approver
9.Approved Date
V2.0



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Table of Contents

Table of Contents





Title: Improved ozone (O3v2)

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Requirements and Design

E3SM Watercycle Group

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The redesigned ozone (O3v2) and algorithms are compatible with and expect the addition of fully interactive tropospheric chemistry that is planned for E3SM V3. It adds the tropospheric ozone loss in the lowermost a few layers (currently set to 4) and removes the resetting to ozone climatology in the troposphere. This changes enables more realistic tropopause changes for simulations such as 4x CO2 and future projections. It also allows us to diagnose the stratosphere troposphere exchange of ozone fluxes, which provide important information about the quality of stratospheric simulations.is interactive with the linearized stratospheric ozone and is passively driven in the troposphere by balancing the stratospheric influx with a simple surface sink. This version directly replaces the component in V1 O3 chemistry where the tropospheric O3 is locked into the 2-D Mozart climatology with a  new subroutine for ozone surface sink. This fix enables more realistic simulations near the tropopause in 4x CO2 and future projection runs.  The added surface ozone sink output makes possible the diagnosis of the stratosphere-troposphere exchange of ozone fluxes and the detection of the surface signals from the stratospheric circulations such as Quasi-Biennial Oscillation and Brewer-Dobson circulation. 

Requirements

Requirement: minor changes in the Linoz module and some related physics code

Date last modified:  
Contributors: Qi TangJuno Hsu (Unlicensed)Michael J Prather


Each requirement is to be listed under a ”section” heading, as there will be a one-to-one correspondence between requirements, design, proposed imple- mentation and testing. Requirements should not discuss technical software issues, but rather focus on model capability. To the extent possible, require- ments should be relatively independent of each other, thus allowing a clean design solution, implementation and testing plan.


Algorithmic Formulations

Design solution:  Add the ozone sink by applying an e-folding decay to 30 ppb with a 2-day

e-folding time. Turn off the resetting to climatology ozone in the troposphere and ozone dry deposition

time scale within the four lowermost layers of the atmosphere.  Turn off the code that resets the ozone values to climatological values in the troposphere. Also take ozone off from the dry deposition list.

Date last modified:  
Contributors: Qi TangJuno Hsu (Unlicensed)Michael J Prather


For each requirement, there is a design solution that is intended to meet that requirement. Design solutions can include detailed technical discussions of PDEs, algorithms, solvers and similar, as well as technical discussion of performance issues. In general, this section should steer away from a detailed discussion of low-level software issues such as variable declarations, interfaces and sequencing.


Design and Implementation

Implementation: Pull requests implemented O3v2 (https://github.com/E3SM-Project/E3SM/pull/3047)

Date last modified:  
Contributors: Qi TangJuno Hsu (Unlicensed)Michael J Prather


This section should detail the plan for implementing the design solution for requirement XXX. In general, this section is software-centric with a focus on software implementation. Pseudo code is appropriate in this section. Links to actual source code are appropriate. Project management items, such as svn branches, timelines and staffing are also appropriate. How do we typeset pseudo code?


Planned Verification and Unit Testing 

Verification and Unit Testing: 5-year and 20-year tests

Date last modified:  
Contributors: Qi TangJuno Hsu (Unlicensed)Michael J Prather


A 5-year test with O3v2 was done run with O3v2  is first implemented and compared with the 5-year control run with the ozone in E3SMv1. The climate climates of these two runs are remain very similar. The magnitude of the O3v2 tropospheric loss looks reasonable and shows signs of approaching a stable state. approaches a state balancing the stratospheric influx within a couple of months from an initial state taken from O3v1.  An extended 20-year test confirmed further confirms that the O3v2 was is implemented correctly and produced produces the expected results.

Planned Validation Testing 

Validation Testing: 20-year test and 4x CO2 simulation

Date last modified:  
Contributors: Qi Tang


The 20-year simulation was is complete (as mentioned above). It verifies that the code is implemented correctly and the results are reasonable. A 4x CO2 is planned to verify the O3v2 with larger perturbations and examine the climate sensitivity changes.

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)


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?


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