Technical specification on the implementation of a trajectory model

The trajectory model FLEXTRA has been implemented as a tool that can be used in different analyses of the situation arisen after accidental release of airborne harmful material. This report gives the reader the technical specification of the implementation of a trajectory model FLEXTRA that can be used by the administrator and by the user. Some aspects of operational elements are also presented. The report contains description of general structure and in details pre-processing and post-processing utilities. In the appendixes developed software is included.