One of the major new technical challenges for distributed simulations is the distribution and presentation and distribution of the natural atmosphere-ocean-space environment. The natural terrain environment has been a part of such simulations for a while, but the integration of atmosphere and ocean data and effects is quite new. The DARPA synthetic environments (SE) program has been developing and demonstrating advanced technologies for providing tactically significant atmosphere-ocean data and effects for a range of simulations. A general-purpose data collection, assimilation, management, and distribution system is being developed by the TAOS (Total Atmosphere-Ocean System) Project. This system is designed to support the new high level architecture (HLA)/run- time infrastructure (RTI) being developed by the Defense Modeling and Simulation Office (DMSO), as well as existing distributed interactive simulation (DIS) network protocols. This paper describes how synthetic natural environments are being integrated by TAOS to provide an increasingly rich dynamic synthetic natural environment. Architectural designs and implementations to accommodate a range of simulation applications are discussed. A number of enabling technologies are employed, such as the development of standards for gridded data distribution, and the inclusion of derived products and local environmental features within 4-dimensional data grids. The application of TAOS for training, analysis, and engineering simulations for sensor analysis is discussed.