极地研究

极地研究 ›› 2005, Vol. 17 ›› Issue (3): 193-202.

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极隙区纬度太阳活动高年背景电离层特征

柳一村;马淑英;蔡红涛;K Schlegel;   

  • 出版日期:2005-09-30 发布日期:2005-09-30

THE BACKGROUND IONOSPHERIC PROFILES AT POLAR CUSP LATITUTES——ESR OBSERVATIONS

  • Online:2005-09-30 Published:2005-09-30

PDF (PC)

1631

被引次数

39

摘要：

本文利用 EISCAT-Svalbard 雷达1999年3月至2003年2月期间观测数据,对太阳活动高年前后极区电离层 F 区电子密度随高度和地方时的二维分布进行统计分析,研究极隙/极盖区背景电离层特征,并与 IRI-2001模式预测结果进行比较。分析结果表明,在 ESR 雷达所在纬度,不存在“冬季异常”现象;但首次发现,此处电离层冬季日变化存在磁午夜前主极大。另外,无论在什么季节,白天时段 ESR 雷达上空电子密度都在磁正午附近有一极大值。与 IRI 模式的比较表明,模式预测的 F 区电子密度与 ESR 实测结果存在较大偏差,在500km 高度以上的顶部电离层和冬季,差别尤其明显。简要讨论了软粒子沉降对造成电子密度日变化磁正午极大的作用和冬季磁午夜前主极大的形成机理。

关键词: 极区电离层;极隙区;软粒子沉降;ESR 雷达;IRI 模式

Abstract:

With EISCAT-Svalbard Radar observations from March,1999 to February,2003,a statistical analysis is made on the electron density variations in different seasons around solar maximum to in- vestigate the characteristics of background ionosphere at polar cusp latitudes.It is found that the so- called “winter anomaly”does not exist in the concerned area and for the first time,a major maxi- mum of electron density is found before local magnetic midnight in winter over ESR site.Besides, there always exists a maximum of electron density around local magnetic noon during daytime in all three seasons.The ESR observation results are compared with the IRI-2001 model,showing signifi- cant distinctions,especially in topside ionosphere above 500 km altitude and winter season.The importance of soft particle precipitation on the formation of the electron density maximum at local magnetic noon is discussed briefly,along with the mechanism of the pre-magnetic-midnight major peak in the winter.