Variation in the line properties along the blue-shifted jet lobe. From top to bottom panel: intensity profiles of the lines, PSF corrected jet half width half maximum (HWHM) at Hα, observed ratios [S II] λ671/[S II] λ671 and [N II] λ658/[S II] (λ671+λ673), and radial velocities of lines. The red line shows the fitting result of the data in the fitting region, which gives a jet radius of 0.65 ± 0.87 au at the star, before correcting for the inclination effect. The gray dashed lines represent the minimum [S II] ratio and the maximum [N II]/[S II] ratio observed at the outer region in Ellerbroek et al. (2014), respectively.