On the eastward geomagnetic field variations at electrojet stations

67-74The paper describes the daily and seasonal variations of declination (or eastward geomagnetic field) at five equatorial electrojet observatories operating during 1958. The daily variation of declination in Central Asian sectors (Addis-Ababa and Trivandrum) showed a completely opposite character between the two solstices. The daily variation of declination at Huancayo showed a strong daytime peak during any of the seasons and at Jarvis during March and December. These abnormalities are suggested to be due to the different ionospheric electric conductivity profiles and due to complex dynamics caused by varying interaction between geographic and magnetic equators at different longitudes