Land working group, meeting notes 2025

Land Surface Working Group
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Date: 21 January 2025

Attendees:

Agenda:

  1. Meeting schedule
  • The meetings keep the same schedule as last year, on the first and third Tuesdays of the month. You can find .ics files in the Announcement topic to add the meetings to your calendar.
  • There is a problem with daylight saving time in some calendars with the meetings appearing to change time. We will warn people closer to the date.
  1. Co-chairs
  • We had one volunteer to become a co-chair.
  • Waiting on the SAC meeting on February 13th to get approval before moving forward.
  • We still accept further applications.
  1. Configurations for CABLE and JULES and CABLE pre-processor

  • Summary of work so far:

    • Mat’s workflow with ANTS for JULES ancillaries outside of ANTS framework.
    • Abhaas working on a met forcing pre-processing tool to format various datasets to a common format for CABLE to use.

  • Soil type discussion:

    • Update the source of the soil types
    • Dominant vs area-weighted method: we prefer to use the area-weighted method. Analysis from Siyuan shows the results are weird over dry regions.

Use the same ancillary sources as what the Bureau is using for JULES. The Bureau is using the default methods and datasets from the Met Office for other ancillaries except for land cover and LAI climatology.

  • Soil parameters

    • JULES read in the soil properties, not the soil types. Soil properties are an output from ANTS.
    • CABLE can calculate the parameters internally but we can also give the distribution of the parameters. Better to converge on a single way to handle it, putting it all in the pre-processing step.
    • JULES and CABLE don’t have the same soil parameters. ANTS will give us most of what we need for CABLE but not all. Units and sign conventions might not be the same as well, we will need to check carefully. We can modify the ANTS app to obtain what we need for CABLE.
    • We can check against Mengyuan’s Australia-wide gridinfo file and BIOS gridinfo.
    • Datasets: proposing the Gridded Soil Atlas.
    • The ground water scheme needs additional parameters to add. They are derived from the elevation so should be easy to obtain.

  • Initial conditions in CABLE gridinfo:

    • Should we keep the initial conditions as part of gridinfo? It might be best to split them from the constant parameters.
    • With a spin-up, the ICs only need to be reasonable and don’t need to be completely consistent with each other. For the slower parts of the model, it is worth thinking carefully about the initialisation.
    • We don’t want to use the restart file format for the initial conditions because the restart format is a 1D vector.

Question of priority of tasks and goal of this work considering coupled and NextGen JULES current work. But NextGen JULES could be several years away and we might need something before that.
One goal for this work is to have a standard way to create inputs for CABLE offline and the regional model. Ideally, it can work within the regional nesting suite.

  1. Met forcing pre-processor for CABLE
  • Discussion around the weather generator. It has been decided that the weather generator should be done outside of CABLE because that’s the only way to properly compare CABLE and JULES. It is also more flexible.
  1. CalLMIP discussion
  • Ian put the question of whether we should get involved with CalLMIP now.
  • There is some interest around parameter calibration but we can’t see any capacity to engage at this stage. We could engage in the webinar in fall 2025 (northern hemisphere).
  1. Sensitivity to root distribution
  • Test with Haverd2013 fwsoil does not help with the issue reported last year.

Actions:

  • List of what datasets are currently used in the ANTS workflow
  • Check what ANTS produces compared to what CABLE needs, Mat and Lachlan