Diurnal and Seasonal Variations in the Ionosphere during the Years 1933 and 1934

The most important results of daily ionospheric measurements made at Deal, New Jersey, latitude 40° 15′N., longitude 74° 02′ W., over the period from March, 1933, to May, 1934, are given in this paper and may be summarized as follows: 1. There was a definite correlation between the noon value of ionic density of the F1region and magnetic disturbances, a decrease in ionic density being obtained on magnetically disturbed days. 2. The noon value of ionic density of the E and F1region attained a maximum in summer and a minimum in winter whereas the reverse condition, of minimum in summer and maximum in winter, was found for the F2region. 3. The time of maximum ionic density of the F2region varied with the seasons of the year, occurring near noon in winter and near sunset in summer. The paper also shows a series of virtual height contour maps for the four seasons of the year.