A Preliminary Analysis of TEC Observed at Low Latitude Area

An observation of total electron content (TEC) was made in June and July, 1985 at a low latitude area. It is found that the northern crest of equatorial anomaly is somewhat around Guangzhou and Jiangmen with a osscilation to and fro around that position. The observed periods of gravity waves locally produced are less than 20--48 minutes and vary with latitudes. The large scale gravity waves generated in polar region can propagate to Guangzhou, but seldom to Hainan island. Irregularities appear mainly from 20-04 LT and sizes are not large. No dominant eastward drift is observed. Since the minimum of solar activity is approaching bubbles appeared only at Sanya in summer.