A statistical analysis of the power spectra (0.7--5 mHz) of the geomagnetic field components H and D recorded at Terra Nova Bay (Antarctica) during three austral summers close to the maximum of solar activity reveals power enhancements in the H component at ≈3.3, 3.9 and 4.5 mHz, which become more evident during daytime intervals. During intervals characterized by higher solar wind speeds these spectral features more clearly emerge and are also accompanied by other enhancements at lower frequencies (≈1.2, 1.9 and 2.7 mHz). The observed frequencies are close to the ones detected both at auroral and low latitudes.¿ 1997 American Geophysical Union