We present the results of a comparative study conducted in Antarctica using data from the SuperDARN radars and simultaneous geomagnetic field measurements at Terra Nova Bay (TNB, corrected geomagnetic latitude ~80°S). Previous studies have shown that ULF waves in the Pc5 frequency band (2-7 mHz) observed at Terra Nova Bay when the station is close to the dayside cusp, and thus to closed field lines, can be interpreted in terms of signatures of field line resonances occurring at lower latitudes, in that ground-based magnetometers measure spatially integrated signals of the ionospheric currents with scale size less than ionospheric height. The radars, providing the Doppler velocities in the ionosphere at different geomagnetic latitudes, may allow to identify the resonances corresponding to the geomagnetic signals observed at Terra Nova Bay. Introduction. The ULF waves observed at TNB exhibits a magnetic local time (MLT) dependence, characterized by a broad maximum around noon, when the station approaches the dayside cusp and closed field lines. Waves generated by the solar wind (SW), through the Kelvin-Helmholtz instability or the impact of SW pressure pulses or the direct penetration of SW fluctuations, are expected to propagate anti-sunward showing, in the southern hemisphere, a clockwise polarization (CW, looking downward on the Earth) in the morning and a counterclockwise polarization (CCW) in the afternoon. This pattern can be modified by the resonant coupling between compressional waves and Alfven modes: for a given frequency, polarization reversals are predicted at the latitude of the resonant field line, and at the latitude corresponding to the amplitude minimum between the magnetopause and the resonant field line. At high latitudes, due to the diurnal variation of the field line length in the outer magnetosphere, the latitude of the resonant field line has a local time dependence, being significantly higher around local noon with respect to dawn and dusk. Statistical studies of the polarized pulsations at TNB, indicate that for frequencies below 7 mHz four sectors with alternate polarization appear through the day: in the pre-midnight and post-midnight sectors the polarization indicates an anti-sunward propagation, while the reversed sense in the pre-noon and afternoon hours suggests that in the dayside TNB moves toward closed field lines, where signatures of resonances occurring at somewhat lower latitude can be still observed. Indeed, since ionospheric effects smear at ground the magnetospheric field variations, ground magnetometers respond to ionospheric currents over a range of latitudes. The SuperDARN radars provide line-of-sight Doppler velocities of the ionospheric plasma along adjacent beams exploring different latitudes. ULF waves can alter such velocities. In particular, field line resonances cause oscillations in ionospheric plasma by the E'×B drift (E' being the ULF electric field and B the local field) and thus they can be detected in the Doppler velocities along the azimuthal direction. In this study we present an analysis of ULF geomagnetic waves at TNB and simultaneous ionospheric velocities measured in the field of view of SuperDARN radars in the southern polar cap. Results. Significant ULF spectral power is observed for a selected event at TNB (Figure 1). Highly polarized signals are observed between 2 and 4 mHz around 18:30 UT and after 21 UT. The power peaks at 2 mHz during 18-19 UT, and at 2.5 and 4-5 mHz during 21-22 UT. The ellipticity (ε) results to be negative during the first interval and positive during the second, indicating that the polarization sense is CCW before noon (12 MLT=20 UT), and CW in the afternoon. As a matter of fact, in the low-pass (f T = 6 mHz) filtered data we can observe that D precedes H around 18:30 UT, while it is delayed after 21 UT. These features might be the signatures of resonances of lower latitude closed field lines.