Effect of the random noise to the reconstruction of the regularly gridded velocity field: the case of the near-surface flows. Displayed are results with varying noise level: a) input data; b) no noise. Other maps were reconstructed with Wiener-like filtering to deal with random-noise boosting with varying S/N levels: c) S/N 1000; d) S/N 100; e) S/N 20 and f) S/N 10. In each cut, the parallel components are indicated by arrows, while the perpendicular component is indicated by the colour. Colour-scale of all panels is identical. The units of the coordinates are in Mm. The maps of all three components at the depth of 1 Mm are displayed in Fig. 6.