MM5
The Mesoscale Meteorology Model 5 or MM5 for short is a computer program for model calculations for weather forecasting in the middle and regional area, a so-called Limited Area Model .
The program enables the simulation and prognosis of atmospheric circulation and thus numerical weather forecast with resolutions of about 1 to 100 km. It was developed as a "Community Model" at the Pennsylvania State University (PSU) and at the National Center for Atmospheric Research (NCAR).
properties
MM5 is a grid-based model with ground-following coordinates. The main characteristics of MM5 are the multinesting capability including moving nests, non-hydrostatic dynamics, which allows the simulation of processes with a resolution of less than 10 km, complete platform-independent parallelization or vectorization (MPI, OpenMP and HPF) for different computer architectures, four-dimensional data assimilation and a variety of different options for handling the physical processes. These include the formation of clouds and precipitation, exchange processes in the boundary layer and on the ground, as well as long and short-wave atmospheric radiation processes. A soil, snow and vegetation model is connected to calculate the heat and moisture balance in the upper soil layers.
Structure and components
In addition to the actual MM5 simulation program, the complete model system consists of a chain of pre- and post-processor programs. The first module of the preprocessor chain (TERRAIN) defines the model area and prepares geographic input data, including orography , vegetation and soil type . Subsequently, meteorological input data (atmospheric flow, humidity, temperature and geopotential fields given on pressure surfaces, as well as the ground pressure field) from global circulation models are processed by a further module (REGRID). The meteorological input data set can be supplemented by additional ground and radiosonde observations (RAWINS or LITTLE_R). Another module (INTERP) performs a vertical interpolation of the atmospheric input data from the pressure areas to the terrain-following coordinates used by MM5 and provides initial conditions as well as the boundary conditions required for the entire simulation period. This is necessary because MM5, as a limited area model, only views a limited part of the atmosphere. A detailed description of all MM5 options as well as all pre- and postprocessor programs can be found on the MM5 homepage and at Dudhia (2000).
MM5 will no longer be further developed as of version 3.7, as the successor model, Weather Research and Forecasting Model (WRF), developed by NOAA , has already been published in version 3.1 and is available to users worldwide.
credentials
- (Grell, 1994) Grell, GA, Dudhia, J. and Stauffer, DR, 1995. A description of the fifth generation Penn State / NCAR mesoscale model (MM5). Technical report, National Center for Atmospheric Research, Boulder, Colorado, USA. NCAR / TN-398 + STR.
- (Dudhia 1993) Dudhia, J., A nonhydrostatic version of the Penn State-NCAR mesoscale model: Validation tests and simulation of an Atlantic cyclone and cold front, Monthly Weather Review, vol. 121, pp. 1493-1513,1993
- (Dudhia 2000) Dudhia, J., PSU / NCAR Mesoscale Modeling System Tutorial Class Notes and User's Guide: MM5 Modeling System Version 3, NCAR, 2000