HIGH-RESOLUTION OBSERVATIONS OF THE POLAR MAGNETIC-FIELDS OF THE SUN

High-resolution magnetograms of the solar polar region were used for t he study of the polar magnetic field. In contrast to low-resolution ma gnetograph observations which measure the polar magnetic field average d over a large area, we focused our efforts on the properties of the s mall magnetic elements in the polar region. Evolution of the filling f actor - the ratio of the area occupied by the magnetic elements to the total area - of these magnetic elements, as well as the average magne tic field strength, were studied during the maximum and declining phas e of solar cycle 22, from early 1991 to mid-1993. We found that during the sunspot maximum period, the polar regions were occupied by about equal numbers of positive and negative magnetic elements, with equal a verage field strength. As the solar cycle progresses toward sunspot mi nimum, the magnetic field elements in the polar region become predomin antly of one polarity. The average magnetic field of the dominant pola rity elements also increases with the filling factor. In the meanwhile , both the filling factor and the average field strength of the non-do minant polarity elements decrease. The combined effects of the changin g filling factors and average field strength produce the observed evol ution of the integrated polar flux over the solar cycle. We compared t he evolutionary histories of both filling factor and average field str ength, for regions of high (70 degrees-80 degrees) and low (60 degrees -70 degrees) latitudes. For the south pole, we found no significant ev idence of difference in the time of reversal. However, the low-latitud e region of the north pole did reverse polarity much earlier than the high-latitude region. It later showed an oscillatory behavior. We sugg est this may be caused by the poleward migration of flux from a large active region in 1989 with highly imbalanced flux.