Meng-Che Wu(NCU), Jen-Kai Hsu(NCU), Ian-Lin Lai(NCU),Wing-Huen Ip (NCU)
From the first Saturn Orbit Insertion in July 2004 to the Final Plunge into Saturn's atmosphere on September 15, 2017, the Cassini spacecraft had made 23 close encounters to Enceladus. Some of them followed very similar flyby trajectories (e.g., E14, E17, E18 ..?) going though the gas plume emitted from the South Pole at different times. A statistical study of the measured chemical composition of the neutral gas species by the Ion and Neutral Mass Spectrometer (INMS) can be used to infer possible presence of time variation in the plume activity. Furthermore, compositional difference found by comparing INMS measurements obtained at different encounter geometries could provide useful information on the spatial distribution of the plume sources in the vicinity of the so-called Tiger Stripes.