Date

 

Attendees

Goals

  • Q&A regarding prototype implementation of tile variables in GRIB2.

Discussion items

See the presentation Tile template Q&A here.

Item

Who

Notes

Presentation regarding some questionsMatt Griffith
  • Q: StatisticalProcess: I have not been able to encode variables such as T2MMAX/MIN. As I understand it, this is because the template definition file needs to include statistical processing. There may be other variables that depend on similar definitions files?

    • A: We intend to add time-integrated parameters once we have instantaneous ones all working correctly, so t2mmax/min would certainly be in the pipeline. For example, we may have 4 total templates for tiles, as is done for other template styles; see below:

  • Q: tileClass: I have used the tileClass groupings from 1000 and onwards, as we encode SURFEX variables. But there is no urban group, this is only under common classes. Is this ok or should there be an urban grouping?

    • A: There should be an urban grouping specific to yours also, however the only grouping information I know is what you provided in the veg-type patches pdf. I am happy to add as many groups as you have in the model for grouping the ECOCLIMAP tiles, so please just let me know if you have any others (for all 33 tiles).b

  • Q: tileAttributes: As I see it, this key is mostly relevant for other surface models, but seems useful for the ocean tile, at least, where you have both T2M_SEA and T2M_SEAICE. However, on the sea ice you also have snow cover, so what is the proper way to encode it? As tileAttribute 2, 4 or 6?
    • A: The best option would be to use the sea/ocean tile with ice covered and or snow covered as a tile attribute (attribute as appropriate, 6 is both)
  • Q: Snow variables: So far I have used snow depth for the WSN_ICE_XX, and applied snow layers for levels, but is that correct? If not, this is a new parameter that needs grib2 codes. There are possibly more than this.

    • A: For WSN you may want param 228038, WMO ID 2/3/23. This is "Liquid water in snow pack". But encoding on snow levels seems the correct thing to do!

  • See the presentation for more details.

Example and discussionAll
  • An GRIB file using the 5-patch surfex output with no coverage was given as an example.
    grib_ls of tile namespace:

    grib_ls of parameter namespace:

We will communicate more in between, but next official meeting 9am  . In particular, I will go through a worked example with Søren using two patches and Trygve is working on a grouped, documented example of SURFEX output.

The deadline is early to mid March to submit a proposal to WMO. We need to talk about other DE330 variables before then also.

Action items

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