曲靖E区场向不规则体回波特征观测研究  

Statistical study on E-region field-aligned irregularities observed by Qujing VHF radar

作　　者：朱云舟 邓忠新[1] 赵振维[1] 徐彤[1] 徐彬[1] 刘瑶 ZHU Yunzhou;DENG Zhongxin;ZHAO Zhenwei;XU Tong;XU Bin;LIU Yao(National Key Laboratory of Electromagnetic Environment,China Research Institute of Radiowave Propagation,Qingdao 266107,China)

机构地区：[1]中国电波传播研究所电波环境特性及模化技术重点实验室,青岛266107

出　　处：《电波科学学报》2019年第2期216-224,共9页Chinese Journal of Radio Science

基　　金：电波环境特性与模化技术重点实验室基金(20171701012;20180101)

摘　　要：利用曲靖VHF相干散射雷达2016年3月至2018年2月间持续观测数据,对电离层E区场向不规则体(field-aligned irregularities, FAI)回波形态特征进行统计分析,结果表明:E区FAI回波在地方时和高度上呈现出三个高发区间,日侧主要位于07:00—12:00LT和90～105 km,而夜侧两个高发区间分别对应于15:00—01:00LT和90～100 km以及18:00—04:00LT和100～115 km;E区FAI回波发生率还具有明显的季节变化,夏季5—8月是其高发期,而冬季的11和12月发生率为极小; E区FAI回波多普勒速度均在-85～85 m/s变化,而其谱宽主要分布在60 m/s以内,三个区间的平均多普勒速度均仅为数m/s,明显小于其平均谱宽,后者约在20～30 m/s.此外,高度分层研究发现,日侧E区FAI的各层平均多普勒速度总体上为负值,但在96 km高度上下薄层内存在一个小幅正值,而夜侧则以105 km高度为界,其上端各层均为负值,下端各层均为正值.曲靖E区FAI表现出典型的Ⅱ型回波特征,其生成和演变过程源自电离层电子密度梯度漂移不稳定性,子午风和低F区电场在其中起着重要作用.Using the data of the VHF coherent scatter radar in Qujing from March 2016 to February 2018,the morphological characteristics of the ionospheric E-region field-aligned irregularities(FAI)echo are statistically analyzed.The results show that the E-region FAI echoes preferentially occur in three areas,the daytime echoes mainly appear during 07:00-12:00LT at an altitude of 90-105 km,while the two nighttime echoes are clearly visible during 15:00-01:00LT at an altitude of 90-100 km and during 18:00-04:00LT at an altitude of 100-115 km,respectively.Moreover,E-region FAI echoes exhibit distinguishable seasonal variation,i.e.,maximum occurrence during May to August,but the minimum occurrence in November and December.The Doppler velocity of these three echoes varies between-85 m/s and 85 m/s with a spectral width of 0-60 m/s,and the mean Doppler velocity is only several m/s which is much smaller than the mean spectral width(20-30 m/s).In addition,we find that the mean Doppler velocity of echoes in the daytime E-region is generally negative,but with a small positive value in the thin layer around the height of 96 km.However,the nighttime E-region is obviously separated by a height of 105 km where the upper are negative,but the lower are positive.The characteristics of E-region FAI in Qujing is typical of typeⅡ.The generation and evolution process are attributed to ionospheric electron density gradient drift instability in which the meridional wind and low F-region electric field play an important role.

关 键 词：电离层 VHF相干散射雷达 E区场向不规则体 梯度漂移不稳定性 

分 类 号：P352[天文地球—空间物理学]