Proxy of spurious velocity in the SPICE Ne VIII 77.04 nm line estimated by intensity gradients. Panels (a) and (b) show 2-D histograms of Doppler velocity vs. Intensity gradient along the raster (x) and slit (y) directions, respectively. Red lines show linear regression fits, with Pearson correlation coefficients r indicated in the upper-left corners. Shaded yellow areas denote pixels excluded from linear regression, having intensity gradients within ±1σ. Panels (c) and (d) compare measured Doppler velocities and proxies of spurious velocity estimated by the regression slopes shown in Panels (a) and (b). The eastern upflow region is highlighted by the green ellipses, whereas dashed magenta circles outline the prominent spurious velocity patterns. Link to the Jupyter notebook creating this figure: 📘.