"Dramatic incidences of marine pollution, such as the Deepwater Horizon oil well blowout and the wreckage of the oil tanker Exxon Valdez, have highlighted the potential for human-caused environmental damage. In attempting to mitigate or avoid future damage to valuable natural resources caused by marine pollution, research has been undertaken by the scientific community to study the processes affecting the fate and distribution of marine pollution, and especially to model and simulate these processes. One area of research is the computerized Lagrangian transport or trajectory model (ASCE, 1996). Trajectory models attempt to predict the movement of actual or hypothetical pollution spills. Needless to say, all existing computerized trajectory models have their virtues and their defects. It is probably not possible to devise a single computational model or framework to satisfy all users. In developing GNOME, we have tried to balance the contradictory notion of a comprehensive model that is both easy to use and which rapidly produces useful and accurate results. This is especially important since GNOME is primarily a forecaster tool. GNOME, version 1.3.5, is an interactive environmental simulation system designed for the rapid modeling of pollutant trajectories in the marine environment. The overall design is that of modular and integrated software. Inputs to GNOME include: maps, bathymetry, numerical circulation models, location and type of the spilled substance, oceanographic and meteorological observations, and other environmental data. The output from the model consists of graphics, movies, and data files for post-processing in a geographic information system (GIS) or NOAA Emergency Response Division's (ERD1) in-house model GNOME Analyst"--Overview.