Global Mesoscale Modeling

Current computing capacity enables GMAO to simulate the entire globe at spatial resolutions previously only possible with regional models. These "global mesoscale model" simulations serve for forefront evaluations of model performance and form the basis for Observing System Simulation Experiments.

Alongside the need to predict weather at fine, localized scales, global mesoscale modeling has two main applications in the GMAO. First, it is essential for NASA to be able to simulate existing and future types of observations with a resolution that is close to the footprint size of the satellite instruments. GMAO's activities in this area include application of global mesoscale models to simulate the atmospheric state with fine spatio-temporal detail. This applies to representations of weather, such as winds, clouds, and precipitation, as well as to the distributions of atmospheric pollutants. Second, as increased computing power routinely allows the use of models with finer spatial resolution and physical complexity, GMAO is pioneering the use of ultra-high-resolution global mesoscale models.

Testing the fidelity of these models today is one step towards the evaluation of the systems that will be in routine use for weather forecasting within the next five to ten years. One aspect of this work is the application of high-resolution versions of GEOS-5 to "climate downscaling" which has typically been performed using regional models.