Air parcel trajectories are commonly employed to identify the origin of air parcels. The recent increase of interest on the emission inventory of polluted air and a usefulness of trajectory analysis for understanding dynamical and chemical aspects of the atmosphere have promoted the usage of trajectories. Following the increasing demands for trajectory models, the National Institute of Polar Research (NIPR) has undertaken the development of kinematic and isentropic trajectory models. The new Meteorological Field Display System has also been developed for plotting various sections of meteorological data.