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 F
1
region 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 F
1
region 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 F
2
region. 3. The time of maximum ionic density of the F
2
region 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.