海南地区扩展F的季节变化研究

Seasonal variation of ionospheric spread-F observed in Hainan

对2002年3月～2005年2月期间海南地区DPS-4测高仪观测到的扩展F资料按照频率、区域、混合和强区域扩展等四种类型进行了分析研究。结果表明:在太阳活动高年(2002年),频率扩展不够活跃;区域扩展主要活跃在夏末秋初的7、8和9月份;混合扩展主要活跃在春季的3月份;强区域型扩展则主要活跃在春秋季的3、4和9月份。在太阳活动中年(2003和2004年),频率扩展主要活跃在夏初的5、6月份;区域扩展主要活跃在2004年的秋季9月份,而2003年各季均不够活跃;混合扩展主要活跃在2003年冬季的12、1(2004)月份和2004年的夏季6、7月份;强区域型扩展则主要活跃在2003年秋季的10月份和2004年春季3、4月份以及夏末深秋的8、10月份。海南地区扩展F的特性与巴西Paulista台站的观测结果相比较主要在季节变化上有很大的不同,与印度Ahmedabad台站的观测结果相比较则主要在季节出现率上有较大的差异。

Using the spread-F （SF） data observed by the DPS-4 digisonde at Hainan ionospheric observatory station from March 2002 to February 2005, the properties of four types of SF, i. e. , frequency, range, mixed, and strong SF, are statistically studied. The results show that during the high solar activity year （2002） the Fre- quency SF （FSF） seldom took place. The Range SF （RSF） mainly took place in Ju- ly, August and September. The Hybrid SF （HSF） mainly took place in March. The Strong SF （SSF） mainly took place in March, April, and September. During the middle solar activity years （2003 and 2004）, the FSF mainly took place in May and June. The RSF seldom took place in every month of 2003 and mainly took place in September 2004. The HSF mainly took place in December 2003 and January, June, and July 2004. The SSF mainly took place in October 200a and March, April, August, and October 2004. The main difference between Hainan and Paulista （Brazil） lies in seasonal variation and the main difference between Hainan and Ahmedabad （India） lies in the seasonal occurrence rate.