LONG-PERIOD GEOMAGNETIC-FIELD FLUCTUATIONS AT TERRA-NOVA BAY (ANTARCTICA)

A statistical analysis of the power spectra (0.7 - 5 mHz) of the geoma gnetic 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 approximate to 3.3, 3 .9 and 4.5 mHz, which become more evident during daytime intervals. Du ring intervals characterized by higher solar wind speeds these spectra l features more clearly emerge and are also accompanied by other enhan cements at lower frequencies (approximate to 1.2, 1.9 and 2.7 mHz). Th e observed frequencies are close to the ones detected both at auroral and low latitudes.