E layer dominated ionosphere observed by EISCAT/ESR radars during solar minimum
E layer dominated ionosphere observed by EISCAT/ESR radars during solar minimum
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EISCAT/ESR 雷达在太阳极小期观测到 E 层主导的电离层
DOI：
10.5194/angeo-32-1223-2014
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发表时间：
2014-05
影响因子：
1
通讯作者：
Ma S Y
中科院分区：
文献类型：
--
作者：
Cai H T;Li F;Shen G;Zhan W J;Zhou K J;Ian W. McCrea;Ma S Y
抽象。根据Mayer和Jakowski（2009年）的研究，E层主导电离层（ELDI）的周期被定义为以垂直电子密度分布为特征，在E层高度处具有最大密度。在本文中，ELDI间隔的特性进行了研究，重点是它们的时间变化，使用EISCAT和ESR雷达在2009-2011年期间的现场对准测量。使用简单但合理的标准识别ELDI事件，其中需要最短的持续时间来排除测量中随机误差引起的可能的“假”事件。结果表明，在冬季和早春观测到的ELDIs比其他季节多，特别是在极光区。ELDI间隔的出现在极光纬度的地磁午夜附近达到峰值，而在ESR纬度的地磁中午附近达到最大值。我们的研究结果意味着，ELDI间隔似乎是一个零星的，而不是一个有规律的现象，与以前的结果推断，从无线电掩星测量的分歧。两个雷达观测到的ELDI事件的典型持续时间之间的差异是显着的，在特罗姆瑟平均为30分钟，但在斯瓦尔巴群岛约为一半。在ELDI间隔期间，E层的平均厚度在两个站点非常接近，HmE和NmE /NmF 2的比值也是如此。案例研究证实，无论是额外的E层电离或F层密度耗尽单独可能导致ELDI的存在。然而，基于对各种类型的ELDI间隔的仔细检查，我们认为它们两者在ELDI形成中起着关键作用。
Abstract. According to the study by Mayer and Jakowski (2009), periods of E layer dominated ionosphere (ELDI) are defined as being characterized by vertical electron density profiles having a maximum density at E layer altitudes. In this paper, characteristics of ELDI intervals have been investigated, focusing on their temporal variations, using field-aligned measurements from the EISCAT and ESR radars during the interval 2009–2011. ELDI events were identified using simple but reasonable criteria, in which a minimal duration was required to exclude possible "fake" events induced by random errors in measurements. It was found that ELDIs were observed more often in winter and earlier spring than other seasons, especially in the auroral zone. The occurrence of ELDI intervals peaks around geomagnetic midnight at auroral latitudes, while it reaches a maximum around geomagnetic local noon at the latitude of the ESR. Our results imply that ELDI intervals appear to be a sporadic rather than a regular phenomenon, in disagreement with previous results inferred from radio occultation measurements. The discrepancy between the typical durations of ELDI events observed by the two radars is remarkable, being 30 min on average at Tromso but about a half of this at Svalbard. During intervals of ELDI, the mean thicknesses of the E layer are quite close at the two sites, as are the values of HmE and the ratio of NmE / NmF2. Case studies confirm that either extra E layer ionization or F layer density depletion alone could lead to the presence of ELDIs. Based on a careful check on ELDI intervals of various types, however, we suggest that both of them play a critical role in ELDI formation.
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影响因子：
10.3
作者：
B. Hultqvist;M. Oieroset;G. Paschmann;R. Treumann
通讯作者：
B. Hultqvist;M. Oieroset;G. Paschmann;R. Treumann
影响因子：
10.3
作者：
L. Lyons;H. Koskinen;J. Blake;A. Egeland;M. Hirahara;M. Øieroset;P. Sandholt;K. Shiokawa
通讯作者：
L. Lyons;H. Koskinen;J. Blake;A. Egeland;M. Hirahara;M. Øieroset;P. Sandholt;K. Shiokawa
影响因子：
--
作者：
FARLEY, DT;BALSLEY, BB;MCCLURE, JP
通讯作者：
MCCLURE, JP
影响因子：
1.9
作者：
H. Cai;Shuying Ma;Y. Fan;Yi Liu;K. Schlegel
通讯作者：
H. Cai;Shuying Ma;Y. Fan;Yi Liu;K. Schlegel
影响因子：
--
作者：
D. Strickland;R. Meier;J. Hecht;A. Christensen
通讯作者：
D. Strickland;R. Meier;J. Hecht;A. Christensen