An explanation for the seasonal dependence of midlatitude sporadic E layers
An explanation for the seasonal dependence of midlatitude sporadic E layers
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DOI：
10.1029/2007ja012322
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发表时间：
2007-06
影响因子：
--
通讯作者：
C. Haldoupis;D. Pancheva;W. Singer;C. Meek;J. MacDougall
中科院分区：
文献类型：
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作者：
C. Haldoupis;D. Pancheva;W. Singer;C. Meek;J. MacDougall
[1]中纬度零星的E层形成时，金属离子的流星起源在较低的热层垂直会聚在风切变。零星E的发生和强度遵循一个明显的季节性依赖，标志着一个明显的夏季最大值。虽然这是已知的，因为早期的电离层探测器的研究，它的原因仍然是一个谜，因为它不能解释的风切变理论的E s的形成。我们在这里表明，零星E的显着季节依赖性与高层大气中零星流星沉积的年度变化密切相关。后者是最近在北方和南半球使用流星雷达干涉仪进行长期测量后确定的。知道的发生和强度的零星E层直接取决于金属离子的含量，这显然是主要由流星沉积，本研究提供了一个因果解释的长期神秘的零星E层的季节依赖性。
[1] The midlatitude sporadic E layers form when metallic ions of meteoric origin in the lower thermosphere are converged vertically in a wind shear. The occurrence and strength of sporadic E follow a pronounced seasonal dependence marked by a conspicuous summer maximum. Although this is known since the early years of ionosonde studies, its cause has remained a mystery as it cannot be accounted for by the windshear theory of E s formation. We show here that the marked seasonal dependence of sporadic E correlates well with the annual variation of sporadic meteor deposition in the upper atmosphere. The later has been established recently from long-term measurements using meteor radar interferometers in the Northern and Southern Hemispheres. Knowing that the occurrence and strength of sporadic E layers depends directly on the metal ion content, which apparently is determined primarily by the meteoric deposition, the present study offers a cause-and-effect explanation for the long-going mystery of sporadic E layer seasonal dependence.