MMM researchers have developed and collaborated on a number of weather models to meet specific research challenges. These include: WRF (Weather Research and Forecast Model); MM5 (Mesoscale and Microscale Model, version 5); Polar MM5/AMPS (Antarctice Mesoscale Prediction System); LES (Large Eddy Simulation Model); Clark-Hall Model; Eulerian Non-hydrostatic model. Descriptions of each, follow.
WRF: The Community Weather Research and Forecast Model (top)
The WRF (Weather Research and Forecasting) Modeling System development project is a multi-year project being undertaken by several agencies. The coordination of this development effort is handled through several layers of joint management, incorporating all of the constituent groups, as well as outside advisory positions.
The ten working groups (usually a representative from each of the major institutions) handle the actual development and testing of the software. Each of the groups is a member of one of the five development teams, with the group leaders generally coordinating their efforts with their team leader.
At the highest level, the scientific issues of the WRF development overseen by the WRF Science Board (WSB). This group is involved in the technical evaluation of the entire WRF package. The WSB may be contacted at wsb@wrf-model.org.
For more information visit the WRF website
MM5: The PSU/NCAR Mesoscale Model version 5 (top)
The PSU/NCAR mesoscale model (known as MM5) is a limited-area, nonhydrostatic, terrain-following sigma-coordinate model designed to simulate or predict mesoscale atmospheric circulation. The model is supported by several pre- and post-processing programs, which are referred to collectively as the MM5 modeling system. The MM5 modeling system software is mostly written in Fortran, and has been developed at Penn State and NCAR as a community mesoscale model with contributions from users worldwide.
The MM5 modeling system software is freely provided and supported by the Mesoscale Prediction Group in the Mesoscale and Microscale Meteorology Division, NCAR.
For more information visit the MM5 website
Polar MM5/AMPS (Antarctic Mesoscale Prediction System): (top)
AMPS employs the Polar MM5, a version of the MM5 (currently V3.4) developed
at the Byrd Polar Research Center. The Polar MM5 contains a number of modifications
to better represent processes in the polar troposphere.
Global 5-day MM5 forecasts that cover Antarctica are run daily. All forecasts
are produced on a 32-processor Compaq ES40 cluster located at NCAR. AMPS and
its hardware are supported by the National Science Foundation.
For more information, see this website
LES: (top)
The current NCAR LES code was first built in 1984 by Moeng (1984) to study clear convective PBLs and since then has continuously evolved to include a variety of physical processes, eg, clouds, chemistry, shear and stable stratification, vegetative surface canopies, and Langmuir cells and wave breaking in the ocean mixed layer (see a partial citation list below). The basic numerical algorithm is a mixed pseudo-spectral finite difference code with third-order Runge-Kutta time stepping utilizing a staggered vertical grid with options for variable spacing. This base algorithm has been extended to a cell centered co-located grid architecture that allows for the resolution of time varying sinusoidal waveforms. The code is written to run on massively parallel computer architectures using the Message-Passing Interface (MPI) and OpenMP programming models. Work in the vertical (z-) direction is partitioned across compute nodes using MPI with horizontal (x-y) work split across multiple OpenMP threads.
For more information, see this webpage
Clark-Hall: (top)
The three-dimensional, non-hydrostatic anelastic meteorological model described by Clark (1977), Clark and Hall (1991), and Clark et al. (1996), exploits features such as two-way interactive grid nesting and vertically-stretched terrain-following coordinates. The model uses a bulk parameterization for both the liquid and ice phase. The liquid phase is parameterized according to a modified version of the Kessler (1969) scheme, with Simpson and Wiggert's (1969) autoconversion formula. In this scheme, liquid water exists as cloudwater and rainwater. The ice phase parameterization uses the Koenig and Murray (1976) ice microphysical scheme. The Koenig-Murray formulation treats two types of ice particles: pristine ice (Ice A) - ice crystals initially formed by heterogeneous nucleation or ice splinter processes due to riming, and ice particles (Ice B) - also called graupel and initially formed by the freezing of raindrops or the interaction of Ice A particles with raindrops. This ice scheme is described, in detail, by Bruintjes et al. (1994). In summary, the model carries microphysical variables of water vapor, cloud water mixing ratio, rain water mixing ratio, and number concentration and mixing ratio for two types of ice particles.
For more information, contact Bill Hall
Eulerian Non-hydrostatic model: (top)
Comparisons between the semi-Lagrangian/Eulerian cloud model of Smolarkiewicz and traditional hybrid Eulerian cloud model using simulations of a moist thermal rising from rest and a moist airflow over an isolated topography show excellent performance of the new model in terms of both cost and accuracy. Similar performance of the semi-Lagrangian and forward-in-time Eulerian counterparts of the model were found.
For more information, contact Piotr Smolarkiewicz or Wojtek Grabowski