Tag: models

Technical Working Group Meeting, October 2016

Minutes

Date: 11th October 2016
Attendees:

  • Marshall Ward (NCI, Chair)
  • Aidan Heerdegen (ARCCSS)
  • Nick Hannah (ARCCSS/Breakaway Labs)
  • Justin Freeman and Mirko Velic (BoM)
  • Russ Fiedler and Matt Chamberlain (CSIRO Hobart)
  • Peter Dobrohotoff (CSIRO Aspendale)

Code submissions

  • Mirko submitted major refactoring update to the nudging code for MOM. Three different options depending on namelist. One just sponge, one does nudging, another does adaptive nudging. Added instantaneous update from datafile. Wanted to reproduce the MOM4 behaviour. Tested, and now works. Was broken previously.
  • Can merge, but we need some testing on other coverage. Currently have a dozen test cases. Not sure any touch this, but will run them anyway. Justin suggests they provide a test case which covers some of these sections.
  • Nic asked that if possible functional and formatting changes be separate commits, as it makes approving pull requests much easier
  • Maybe not merge yet, but get testing working to cover this. Justin will look at adapting an existing MOM test case for this purpose.

Exchange grids and smoothing

  • Justin was talking to Paul Sandery about exchange grids. An issue with tiling as a result of remapping. Was asking about how Russ implemented smoothing.
  • If you took interim fields end up with horrible pattern with convergence of winds with 1st or 2nd order remapping due to discontinuity. Russ wrote some code that does 2D smoothing within the surface boundary condition. Bypasses the exchange grid and used the flux exchange to native grids options(?). GFDL apply an interpolation when they read in via data override. So can use the data override to interpolate to the finer grid and can control this.
  • This is only a problem with conservative remapping with exchange grids.
  • Nic didn’t think this was a problem with standard MOM-SIS runs, but Russ said it should still be visible in the fluxes with coarse (1deg) forcing fields.
  • With ACCESS high res ocean the fields and fluxes are extremely blocky, so Nic smooths on the ice grid, before it comes into the ocean grid, on a tile by tile basis.
  • If you want local conservation, cannot get around this. In ACCESS can use linear interpolation and then post-process to get global conservation. Doesn’t work with local conservation.
  • Marshall suggested we have some test cases that don’t run the model but test coupling and fields
  • These effects most often seen when there is a big difference in resolution between model fields and input fields. Look at wind stress fields. Maybe some of the barotropic fields, height and definitely convergence in barotropic restart file.
  • Paul’s runs do not use conservative remapping. Don’t see the horrible features with some of the other schemes.
  • Nic: do we need a central document discussing this?

OceanMaps 4

  • Justin is trying to prototype OceanMaps 4. Picking up on Paul Sandery’s work. He has been using MOM5-SIS and using bulk fluxes to link the models. Would like to standardise, or make these things available. Not sure how it connects to linkage project.
  • Nic felt it was good to know what Paul does. So far no code changes?.

FMS

  • Aidan got a query from Dave Hutchinson, asking if latest version of FMS was included in the code on MOM5 repo. Marshall has updated FMS in the master branch to Ulm, but not to Verona, the latest version.
  • Move FMS to a submodule of MOM5 rather than manually included inline
  • Goal is for Rui Yang (NCI) to work on parallel netCDF in MOM5

Model release naming and definition

  • Still an issue
  • Nic has put an access-om model on OceansAus. Has version controlled input files and code. Can be downloaded, compiled and run.

CICE

  • ACCESS-OM models are using CICE4.?, but Peter is using 5.1.
  • There are many bug fixes and performance improvements in the version of CICE Nic has been working on that would be beneficial to Peter.
  • Peter is working on a refactoring of CICE5.1
  • We should align our work to the same version of CICE.
  • First step is for Peter’s version of CICE5.1 to be hosted on OceansAus and development work to be based from that so we can work together. Some discussion about the best way to do this.

Actions

  • Just and Mirko work up test cases to cover the nudging code and give them to Nic.
  • Nic to add new test cases to Jenkins test suite.
  • Aidan to add mom-ocean.org and mom-ocean.org.au to uptime monitoring service (Uptime Robot).
  • Add Peter’s CICE5.1 config to OceansAus github repo
  • Nic create a discussion document (on COSIMA?) to document current approaches and strategies for future
  • Marshall to move FMS to submodule of MOM5 github repo. Liase with Nic on implementation?
  • Others test Nic’s access-om model config on OceansAus

Technical Working Group Meeting, September 2016

Minutes

Date: 6th September 2016
Attendees:

  • Marshall Ward (NCI, Chair)
  • Aidan Heerdegen (ARCCSS)
  • Justin Freeman and Mirko Velic (BoM)
  • Russ Fiedler and Matt Chamberlain (CSIRO Hobart)
  • Peter Dobrohotoff (CSIRO Aspendale)

General Discussion

  • Aidan described latest tenth model comparison runs, between GFDL50 and KDS75. Models are running well at an ocean time step of 450s, with excellent throughput on raijin. At 600s there is an instability related to a topographic feature off the northern tip of Severny Island. Some modification of the topography is required. Matt might be interested in looking at heat uptake and transport between the models.
  • Matt looking at surface parameterisations. Bulk formula etc. They have some warm biases that seem to be due to the choice of some of these parameters. Looking to optimise parameters to fix this.
  • Peter is working on ACCESS-CM2.. Working on UM 10.* model. Running Jules currently, but will run CABLE. Have run UM8.5/GA6 200+ years. Confusingly was also called ACCESS-CM2. 350 yrs on 0.25 ocean on GA6. All version 10.* versions are using the rose+cylc run architecture.

Model release strategy

  • Need MOM releases tagged.
  • Marshall and Aidan in favour of MOM having a release strategy (slightly separate issue).
  • Justin felt that the COSIMA model is MOM+CICE+OASIS. Don’t want to tag MOM with COSIMA release names.
  • Can use a sub-module approach, bring in specific model revisions.
  • When available, Justin would like Nic’s latest model definition repo to be communicated to the TWG.

New NCI hardware test

  • Marshall has done some very preliminary testing of MOM with a Knights Landing test cluster (~4k cores, 64 core / node Xeon Phi, 92GB/node). 1.3GHz cores. Faster interconnect (EDR v FDR). Supports AVX512 instruction set, so potentially double the number of floats/clock cycle. These are also lower power and cheaper, so could get many more cores than a traditional CPU architecture.
  • MOM is running, and it was very easy to do. Raijin binaries run fine, as does MPI.
  • Old binaries work fine. Ran 2.4x slower than raijin. As you would expect from clock speed alone.
  • Only ran 960 cores.
  • AVX512 enabled binary throws floating point errors a lot.

Actions

  • Aidan to provide Matt with location of tenth model test data. Check if capturing all the diagnostics Matt might be interested in.
  • Matt to provide Marshall with some test cases for the Xeon Phi test cases, maybe 1 deg configurations.
  • Marshall and Aidan to look at COSIMA model release — liase with Nic Hannah.

First meeting of the technical working group

Minutes

Date: 2nd August 2016
Attendees:

  • Marshall Ward (NCI, Chair)
  • Aidan Heerdegen (ARCCSS)
  • Nic Hannah (ARCCSS/Breakaway Labs)
  • Justin Freeman (BoM)
  • Russ Fiedler and Matt Chamberlain (CSIRO Hobart)

Agreed to have monthly videoconference meetings.

COSIMA model definitions on website

  • Who is the audience? Agreed should pitch it at novice researcher/student with no links to existing community
  • Should start by using ourselves as the audience, define them for our use and expand from there
  • First test case should be the ACCESS-OM-025 (Quarter degree MOM+CICE+OASIS-mct)
  • CICE is currently housed on CWS github repo
  • Agreed we need consolidated location for model code. Nic suggested a git repo pulling in model components using submodules. This makes it clean to install and allows for control of versions via explicit commits or tags
  • COSIMA name is taken on github, so agreed to use existing OceansAus group
  • Minimal technical detail on website, instead point to github repo

Input data

  • Data store for model input files – decided to use the ua8 Ramadda location which is currently used for MOM5 test cases
  • Need data versioning

Benchmarking

  • Need example outputs, and timings. Direct users to run the model and compare their outputs and timings to those supplied to verify model integrity and performance
  • Need continuous integration to test against these outputs. Nic currently running a dozen test cases on a Jenkins server for MOM5. Can add these tests too.
  • Essential to allow upgrading of model components with confidence they have not affected model integrity and performance.

Tools/Utilities

  • Desirable to also have related tools and utilities on the OceansAus github site
  • Concerns that the site collect crufty tools, so make some standard for what constitutes a repo: utility, support and documentation?

Model Support

  • How do we support these models? Decided the existing MOM mailing list would suffice for general user questions. Stephen Griffies has been interested in supporting a MOM-CICE configuration. Also github issues can be used for specific code issues.

Mission Statement

  • Desirable to have a general mission statement about what the aims of the TWG
  • Any additional invitees? Perhaps Mirko from the BoM? Open invitation to anyone who wants to attend and contribute

General technical discussion

  • Aidan described progress with improving vertical grid in MOM-SIS 0.1 deg config
  • Justin working on making his real time flythrough data-vis software available on raijin, Maybe use Russ’ BRAN2015 reanalysis dataset with recent El Nino
  • Matt is adding sea-ice to the OFAM grid and tuning parameters to reduce SST biases. Turning off neutral physics helped.
  • Ben Evans wants a WOMBAT test case, perhaps use the 0.25 deg runs Matt did with Paul Spence?
  • Marshall has updated FMS and he and Nic have used Jenkins testing to find and fix bugs. Close to being added to master branch of MOM5

COSIMA website

  • A lot of enthusiasm for contributing blog posts to website from technical perspective.

Actions

  • Aidan to add Nic to OceansAus group
  • Nic to create initial ACCESS-OM-025 repo with submodules for MOM5/CICE/OASIS-mct
  • Justin volunteered to test out initial model config as “new user”
  • Marshall to write draft mission statement