Meteorological models

Dynamic meteorological models, much like air pollution models, strive to describe the physics and thermodynamics of atmospheric motions as accurately as is feasible. Besides being used in conjunction with air quaHty models, they ate also used for weather forecasting. Like air quaHty models, dynamic meteorological models solve a set of partial differential equations (also called primitive equations). This set of equations, which ate fundamental to the fluid mechanics of the atmosphere, ate referred to as the Navier-Stokes equations, and describe the conservation of mass and momentum. They ate combined with equations describing energy conservation and thermodynamics in a moving fluid (72) ... 

R. A. P Ake, Mesoscale Meteorological Modeling AcAeimc Press, Orlando, Pla., 1984. 

The fact that some, although clearly not all, regions of (xq, r) parameter space indicate extraordinary sensitivity to initial conditions clearly precludes many types of prediction taking the example of Lorenz (1963), prediction of the time and location of an individual tornado is not possible, even though meteorological models exist which successfully predict the onset of tornado season. 

Both, off-line and on-line coupling of MetMs and ACTMs are useful in different applications. Thus, a timely and innovative field of activity will be to assess their interfaces, and to establish a basis for their harmonization and benchmarking. It will consider methods for the aggregation of episodic results, model down-scaling as well as nesting. The activity will also address the requirements of meso-scale meteorological models suitable as input to air pollution models. 

There is the independence of atmospheric pollution model runs on meteorological model computations... 

Feedback Mechanisms, Aerosol Forcing in Meso-meteorological Models... 

The on-line integration of meso-scale meteorological models and atmospheric aerosol and chemical transport models enables the utilization of all meteorological 3D fields in ACTMs at each time step and the consideration of the feedbacks of air pollution (e.g. urban aerosols) on meteorological processes and climate forcing. 

History of Coupled Chemistry/Air Quality and Climate/Meteorology Models... 

Typical options for turbulent transport in the boundary layer include a level 2.5 Mellor-Yamada closure parametrization (Mellor and Yamada 1982), or a non-local approach implemented by scientists from the Yong-Sei University (YSU scheme, Hong and Pan, 1996). Transport in non-resolved convection is handled by an ensemble scheme developed by Grell and Devenyi (2002). This scheme takes time-averaged rainfall rates from any of the convective parametrizations from the meteorological model to derive the convective fluxes of tracers. This scheme also parameterizes the wet deposition of the chemical constituents. 

The host meteorological model used for air quality studies is the Global Environmental Multiscale (GEM) model. GEM can be configured to simulate atmospheric processes over a broad range of scales, from the global scale down to the meso-gamma scale. 

The online coupled model system, Enviro-HIRLAM, which integrates a meteorological model and an atmospheric chemical transport model has been described and evaluated. 

Interfacing of self developed AQ models with EU Weather Services and US Community Meteorological Models through model specific or general purpose interfaces... 

A major learning for Australian conditions is that recirculation of pollutants in the sea breeze is an important feature of coastal cities the spatial resolution required of the meteorological model needs to be adequate to resolve the sea breeze phenomenon. Resolution substantially finer than 10 km is required (i.e. 2-5 km seems adequate). 

Experiments have been performed to address the error made by the pre-processor in AirQUIS. Figure 13.2 shows the resulting NO2 forecasts from AirQUIS using dispersion parameters calculated by the pre-processor compared to AirQUIS using dispersion parameters calculated by the meteorological model MM5. 

For consistent calculation of boundary layer parameters in off-line coupling the land-use classes in the meteorological model should ideally match the land-use classes presented in EMEP (Table 13.2). In the coupling with HIRLAM, where only... 

ACTM models can make use of atmospheric parameters that are output from some parametrization schemes. Boundary layer parameters have to be calculated inside ACTM models or in pre-processing if they are not available from the meteorological model. Entrainment and detrainment rates in cumulus clouds could be provided if sufficiently sophisticated cumulus parametrization is used in the meteorological model. 

Technically, the transfer of the information from the ACTM to meteorological model is straightforward. For the operational forecasts, the next cycle meteorological calculations can use the previous cycle chemical composition results. For the case of nested simulations, both re-analyses and forecasts, the next-step nested meteorological computations can utilise the previous-step composition data. 

Meteorological Model High Resolution Limited Area Model (HIRLAM)... 

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