MM5 Modeling System Overview

Features of the Modeling System

Globally re-locatable
- Three map projections:
  - Polar stereographic;
  - Lambert conformal;
  - Mercator.
- Support different true latitudes.
- Variable resolution terrain elevation, landuse, soil type, deep soil temperature, vegetation fraction, and land-water mask datasets are provided (the new global 30 sec terrain data may be obtained from USGS anonymous ftp site).
Flexible and multiple nesting capability
- Can be configured to run from global scale down to cloud scale in one model
- Can be run in both 2-way and 1-way nesting mode:
  - 2-way: multiple nests and moving nests
  - 1-way: fine-mesh model driven by coarse-mesh model
- Nest domain can start and stop at any time.
- Nest terrain file may be input at the time of nest start-up in the model.
Real-data inputs
- Use routine observations
  - Upperair and surface reports, including wind, temperature, relative humidity, sea-level pressure, and sea surface temperature.
- Couple with global models and other regional models
  - Use other model's output either as first guess for objective analysis, or as lateral boundary conditions, e.g. NCEP and ECMWF global analysis, NCEP/NCAR and ECMWF reanalysis, NCEP ETA model.
Non-hydrostatic and hydrostatic (V2 only) dynamic frameworks.
Terrain-following vertical coordinates.
Choices of advanced physical parameterization.
Four-dimensional data assimilation system via nudging.
Adjoint model and 3DVAR.
The MM5 modeling system runs on various computer platforms:
- Cray, SGI, IBM, Alpha, Sun, HP, and PCs running Linux.
Parallelization
- Parallelize on shared-memory machines:
  - Cray (EL, J90, YMP), HP-SPP2000, SGI, SUN, Alpha, and Linux
- Parallelize on distributed-memory machines:
  - IBM SP2, Cray T3E, SGI Origin 2000, HP-SPP2000, Fujitsu VPP, Sun and Linux clusters
Well-documented, and user-support available.