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We present an investigation of line-of-sight (LOS) velocity oscillations in solar faculae and sunspots. To study the phase relations between chromospheric and photospheric oscillations of the LOS velocity, we measured the time lag of the chromospheric signal relative to the photospheric one for several faculae and sunspots in a set of spectral line pairs. The measured time lags are different for different objects. The mean measured delay between the oscillations in the five-minute band in faculae is 50 s for the Si i 10 827Å -He i 10 830Å pair; for the pair Fe i 6569Å -Hα 6563Å the mean delay is 20 s; for the pair Fe i 4551Å -Ba ii 4554Å the mean delay is 7 s; for the pair Si i 8536Å -Ca ii 8542Å the mean delay is 20 s. For the oscillations in the three-minute band in sunspot umbrae the mean delay is 55 s for the Si i 10 827Å -He i 10 830Å pair; for the Fe i 6569Å -Hα 6563Å pair it was not possible to determine the delay; for the Fe i 4551Å -Ba ii 4554Å pair the mean delay is 6 s; for the Si i 8536Å -Ca ii 8542Å pair the mean delay is 21 s. Measured delays correspond to the wave propagation speed which significantly exceeds the generally adopted speed of sound in the photosphere. This raises the question of the origin of these oscillations. The possibility that we deal with slow MHD waves is not ruled out.

An analysis of line-of-sight velocity oscillation in nine solar faculae was undertaken with the aim of studying phase relations between chromospheric (He I 10830 Å line) and photospheric (Si I 10827 Å line) five-minute oscillations. We found that the time lag of the chromospheric signal relative to photospheric one varies from −12 to 100 seconds and is about 50 seconds on average. We assume that the small observed lag can have three possible explanations: i) convergence of formation levels of He I 10830 Å and Si I 10827 Å in faculae; ii) significant increase of five-minute oscillation propagation velocity above faculae; iii) simultaneous presence of standing and travelling waves.

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