Kinematic characteristics of the jets revealed by the NVST Hα observations. a1–a3: time–distance plots derived from the Hα blue wing, line core, and red wing images along the curve “Slice1” shown in Fig. 2a3. The dotted vertical lines mark the initial moments of two rising phases. The dotted oblique lines delineate linear fittings of the front of jet1 in two rising phases. b1–b3: similar to (a1)–(a3), but showing jet2 along the curve “Slice2”.