An Analysis Of The Solar And Lunisolar Daily Variations In The Geomagnetic Field At Sitka, Alaska 1902-1952

摘要

The solar (S) and lunisolar (L) daily magnetic variations in all three elements of the geomagnetic field at Sitka, Alaska (geomagnetic latitude 60°N) have been calculated using the hourly data obtained at that observatory over the past fifty years. The harmonic components of these variations were determined for different seasons and for varying degrees of magnetic and solar activity. The classification according to season was made by the use of season numbers which divided the year into almost equal parts rathern than the previously used divisions into months and quarters. For the classification of days according to magnetic activity, daily character numbers were used which were based on the international daily character figures Ci, as modified by the three hour range index K so as to be applicable to the longitude of Sitka. The classification of days according to solar activity was made using daily class numbers based on the Zurich daily relative sunspot numbers.