Abstract:

The whistler data obtained at the Chinese Great Wall Station, Antarctica, in 1986 are analysed. Statistic study are carried out on morphology, such as whistler activities during magnetic storms, diurnal and seasonal variations of whistler occurrence rate, diurnal variation of dispersion for different geomagnetic activities. The results show that: (1) Occurrence rate of whistlers is related to magnetic storms in a complicated way. For the storms with sudden commencement, the occurrence rate begins to increase 27 hs after storm commencement, and gradually reaches to its maximum. It retains high level for 15 hs, and then decreases to the normal level. While for the gragually commencing magnetic storms, the time lag is 20 hs, and the duration of high level is 5 hs. (2) the diurnal variation of occurrence rate of whistlers is characterized with two peaks, one in the early morning (0300 -0600 LT) and another in the afternoon (1700-2000 LT). These peaks are more or less independent on season and magnetic activity. (3) There is a characteristic seasonal variation in occurrence rate of whistlers. In local winter (June, July, August) the occurrence rate reaches its maximum, while in local summer (December, January and February) the occurrence rate is as small as 1/20 in winter. This result is in agreement with those in Beijing, Mohe and other areas. (4) Diurnal variation of whistler dispersion is correlated with magnetic activities. During quiet days the daily range of whistler dispersion is relatively small, while during the disturbed days the dispersion and its daily range become larger.