Using Numerical Weather Modeling to Customize Synthetic Natural Environments

With continuing cutbacks to Department of Defense budgets, computer simulations are playing a larger and larger role in military training, from virtual simulators to constructive simulation of large scale, joint-service engagements. Two primary objectives of the next generation of simulation systems are 1) the ability to model the natural environment and its effects on weapons systems and sensors, and 2) to provide software tools to allow a simulation exercise planner to customize the synthetic natural environment (SNE) to provide an environmental scenario to meet specific training objectives, while at the same time maintaining high levels of realism and physical consistency. Recently, creation of SNEs has largely been based on historical gridded environmental data products such as those provided by the Defense Modeling and Simulation Office's (DMSO) Master Environmental Library (MEL). These gridded products are generated to support the operational Navy and other services and are generally produced at very coarse spatial and temporal resolution relative to the requirements imposed by distributed simulations. With the very recent availability of numerical models able to run efficiently and dependably in a low-cost workstation environment, and the development of four-dimensional data assimilation techniques, the generation of high-resolution, customized gridded environmental data, including the atmospheric, oceanographic and space regimes, has become feasible. This paper focuses on modeling the atmospheric regime, which has received the greatest attention by the military modeling and simulation community to date due to its complex dynamics and varied phenomenology, to support construction of high-resolution SNEs.

The fifth generation of the Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5) is being integrated by TASC with the Total Atmosphere and Ocean Services (TAOS) system, whose development was sponsored by DARPA and DMSO. TAOS is an environmental server that distributes common environmental data to geographically isolated simulations interoperating on a simulation internet. Integration of the MM5 with TAOS provides the ability for important customization of the atmosphere in synthetic natural environments. Atmospheric resolution and physical parameterizations are now fully configurable and driven by user requirements. The MM5 can be used to create actual weather conditions for a given input region and time, or to drive towards specified weather conditions (i.e. a rain event, etc.) which are deemed necessary to meet desired training goals. Various techniques, including parameter modification, four-dimensional data assimilation and variational data assimilation (3DVAR, 4DVAR) are used to drive the MM5 towards specified conditions. While the MM5 has been widely accepted scientifically, a complex setup process often makes configuration of the model difficult and tedious. To alleviate these problems, a graphical user interface (GUI) has been developed to configure and run the MM5. The GUI allows experienced MM5 users to set any of the low-level MM5 parameters, while allowing novice users to accept appropriate system-selected defaults for nearly all parameters.