Showing papers by "Wuhan University published in 1947"

F2 Ionization and Geomagnetic Latitudes

Abstract: While studying the relation between the anomalous distribution of F2 ionization in the ionosphere and the geomagnetic co-ordinates of various observatories, we found that Sir Edward Appleton had already published his results1 (that issue of Nature was not available to us until two months ago owing to post-war difficulties), showing clearly the symmetry of F2 critical frequencies with respect to the dip angles south and north of the magnetic equator. Later, Prof. S. K. Mitra gave reasons2 explaining the geomagnetic control of F2 ionization, and found that the location of maximum critical frequencies obtained from his calculation agrees very well with that shown by Appleton's result. In our work, the critical frequencies are plotted against the geomagnetic latitudes—Figs. 1 and 2 for March and September 1946. Compared with Figs. 3 and 4, where the critical frequencies are plotted against dip angles, they show a similar appearance of symmetry. I feel, however, that the dip angles as measured near the surface of the earth, inevitably influenced by local factors, may not represent at all well the geomagnetic effect in a region far above the earth such as the F2 region in the ionosphere.