Provided by Chinese Academy of Meteorological Sciences (CAMS), China
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.
GRIST 5km atmosphere-only¶
Atmosphere-only, with land model is Noah-MP. SST and sea ice concentration are prescribed.
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.
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*psapproach for reconstructing (moist) hydrostatic pressure at each model level (or any function that assumes this relationship). One may use
mpressureFacein the model output for vertical interpolation to a constant pressure level.
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