Weather Research Forecast model with

One mesoscale model, i.e., the National Oceanic and Atmospheric Administration (NOAA) s Weather Research Forecast model with Chemistry (WRF/Chem) (Grell et al. 2005 Fast et al. 2006 Zhang et al. 2010a)... 

WRF/Chem The weather research forecast model with chemistry... 

Atmospheric models for research and forecasting of weather, climate, and air quality are all based on numerical integration of the basic equations governing atmospheric behavior. These equations are the gas law, the equation of continuity (mass), the first law of thermodynamics (heat), the conservation equations for momentum (Navier-Stokes equations), and usually equations expressing the conservation of moisture and air pollutants. At one extreme, atmospheric models deal with the world s climate and climate change at the other extreme, they may account for the behavior of local flows at coasts, in mountain-valley areas, or even deal with individual clouds. This all depends on the selected horizontal scale and the available computing resources ... 

In addition to the statistical translation of model output, the forecasters in weather services apply subjective judgments to the model forecasts. In the early days of numerical prediction, subjectively corrected forecasts often beat the score of pure model products. The subjective judgments were based on past performance of the model and comparison with other model forecasts. However, the involvement of forecasters in the daily forecast process is decreasing steadily with time. This is due to improvement in the short- to mediinn-tange prediction systems and the need for more research and development for long-range and seasonal forecasts as well as for severe storm forecasts. 

An area in which supercomputers have become indis-pensible is weather forecasting and research in climatology. The quality of weather forecasts has been increasing steadily with that of the numerical models that describe the motions of air, moisture, and driving forces such as sunshine and temperature differences. The price to be paid for these more refined models is the increased amount of computation to be done. In particular, for weather forecasting the timeliness of the results is of obvious importance, so for more intricate weather models, computers have to be faster to meet the time requirements. 

Computer simulations with an interactive chemistry GCM have been performed at T63 resolution (1.8° latitude and longitude). The chemistry GCM has been described by G.J. Roelofs and J. Lelieveld [Tellus 49B, 38 (1997)] and E. Roecknta- et aL [Journal of Climate, 12 3004 (1997)]. To represent actual meteorology, we assim-ilated analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF), as described by A,T.J. de Laat et al. (35). The T63 resolution model version has been evaluated by A,S. Kentarchos, G.J. Roelofs, and J. Lelieveld Journal of the Atmospheric Sciences, SI 2824 (2000)]. The chemistry scheme includes a representation of higher hydrocarbons as described by G.J. Roelofs and J. Lelieveld Journal of Geophysical Research, 105 22697 (2000)]. 

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