Abstract We analyze oscillation behaviours in chromospheric internetwork regions using spectral observations of the CII 1334 Å line obtained with the Solar Ultraviolet Measurements of Emitted Radiation spectrograph (SUMER) aboard Solar and Heliospheric Observatory (SOHO). Three areas, 26×120arcsec2 each, at the various latitudes from the disk center to the north polar coronal hole, were rastered with a cadence of about 40–60 s in the solar minimum year. We obtained the time evolution of two-dimensional (2D) line intensity, continuum and line core shift. The continuum and the line shift show ~3 min chromospheric oscillations in the internetwork regions underlying the coronal hole as well as at the disk center. We find that the CII 1334 Å line shift oscillates with an average speed of ~1.7km-1, independent of the latitude, while its coherent scale decreases with latitude. On the other hand, the oscillation amplitude of the continuum around the 1334 Å and the phase delay between the Doppler shift and continuum slightly increase with latitude.
Keywords active optics --- telescopes --- instrumentation
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