The ionosphere and solar activity

Summary

The correlation between monthly median critical frequencies and solar activity was determined for Washington, D.C. Results were compared with those from a similar study made for six Arctic stations. For noon data (E, F1 andF2 layers), a greater value off _c (at zero sunspot number) and a slightly greater slope were obtained for Washington than for the Arctic locations. The influence of increased solar activity on the behavior of the midnight ionosphere is discussed.