A PECULIARITY OF THE Sq VARIATION'S VARIATION WITH LATITUDE

Solar quiet daily variations in horizontal H component in three latitudinal ranges at high, moderate and low latitudes are compared during one year (1985). It is found that the solar quiet daily variation amplitude varies strongly with season at high latitudes, with almost complete vanishing of the variation during the winter months, and the same applies to the variation shape at middle latitudes, with smaller intensity, though. In contrast to this, almost constant amplitude and invariable shape are observed during each month of the year at 3 of 4 standard low-latitude stations, but Kakioka. In Kakioka a signature of the annual variation described above is noticed, e.g., the solar quiet daily variation amplitude vanished in 1985 in winter months.