GRIST

Provided by Chinese Academy of Meteorological Sciences (CAMS), China

Model description

GRIST is a unified model system for global weather and climate modeling. Its dynamical core solves the primitive equations but with the vertical acceleration term restored for nonhydrostatic modeling (Zhang et al. 2019; Zhang et al. 2020). The horizontal grid is fully unstructured and uses the Voronoi-style polygon as the primal cell.

The 5-km, nonhydrostatic global model configuration for DYAMOND Winter experiment is a simplified version of the setup used by Zhang et al. (2021). In particular, no cumulus parameterization (shallow, deep) was used.

Experiment runs

GRIST 5km atmosphere-only

Location:

/work/bk1040/DYAMOND/.input_winter_data/GRIST_5km/ (non-standardized data)

Setup:

Atmosphere-only, with land model is Noah-MP. SST and sea ice concentration are prescribed.

Resolution:
  • The horizontal resolution is 5 km (23592962 cells), based on 9-time recursive bisection of a regular icosahedron with a final-step trisection (G9B3).

  • The vertical resolution is 30 layers with a top at 2.25 hPa (~40 km).

  • The nominal model time step is 60 s.

Comments:
  • The atmosphere initial condition comes from IFS-analysis data. The land model is initialized using ERA5 data. SST and sea ice are prescribed.

  • For post-processing the GRIST data, we recommend using CDO to first interpolate the unstructured-mesh data to a regular global (or regional) lat-lon grid. The vertical interpolation can be done using any linear interpolation function.

  • Please note: Because GRIST uses a dry-air-mass-based vertical coordinate, please do not use the typical hyam*p0+hybm*ps approach for reconstructing (moist) hydrostatic pressure at each model level (or any function that assumes this relationship). One may use mpressureFace in the model output for vertical interpolation to a constant pressure level.

Contact person:

Yi Zhang (CAMS) and Jian Li (CAMS)

See also