Origin and Distribution of Daytime Electron Density Irregularities in the Low-Latitude F Region.
Origin and Distribution of Daytime Electron Density Irregularities in the Low-Latitude F Region.
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DOI：
10.1029/2020ja028343
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发表时间：
2020-09
期刊：
影响因子：
--
通讯作者：
Paxton LJ
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文献类型：
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作者：
Kil H;Lee WK;Paxton LJ
在低纬度F区的白昼一侧的电子密度不规则性被认为是夜间等离子体泡的残余（或化石）。我们提供了观测证据的连接白天的不规则性夜间气泡和运输的白天不规则性的背景电离层的垂直运动。利用1999年3月至2004年6月中华民国第一颗卫星的离子密度测量数据，得到了不规则性的分布。低纬地区昼夜不规则性的季节分布和经向分布具有相似性。在夜间经常发生强烈不规则现象的地方，白天不规则现象的发生率很高，这为白天不规则现象与夜间气泡的关联提供了强有力的证据。夜间的不规则性集中在赤道地区，而白天的不规则性则分布在更广泛的纬度地区。日间不规则性纬向传播的季节和经向变化与等离子体密度和垂直速度的形态一致。与等离子体密度相对应的纬向波数为4的模式在白天的不规则性分布中被识别。这些观测结果得出的结论是，低纬F区白天的不规则形态主要是由夜间的气泡形态和白天的电离层喷泉过程所决定的。低纬地区白天和夜间不均匀性的季节和经向分布相似，白天不均匀性的纬向4波型、等离子体密度和垂直速度表现出相似的行为，白天不均匀性的形态取决于夜间气泡的形态和昼侧的喷泉过程
Electron density irregularities on the dayside in the low‐latitude F region are understood as remnants (or fossils) of nighttime plasma bubbles. We provide observational evidence of the connection of daytime irregularities to nighttime bubbles and the transport of the daytime irregularities by the vertical motion of the background ionosphere. The distributions of irregularities are derived using the measurements of the ion density by the first Republic of China satellite from March 1999 to June 2004. The seasonal and longitudinal distributions of daytime and nighttime irregularities in low latitudes show a close similarity. The high occurrence rate of daytime irregularities at the longitudes where strong irregularities occur frequently at night provides strong evidence of the association of daytime irregularities with nighttime bubbles. Nighttime irregularities are concentrated in the equatorial region, whereas daytime irregularities spread over broader latitudes. The seasonal and longitudinal variation of the latitudinal spread of daytime irregularities is consistent with the morphologies of plasma density and vertical plasma velocity. The zonal wave number 4 pattern, which corresponds to that in plasma density, is identified in the distribution of daytime irregularities. These observations lead to the conclusion that the morphology of daytime irregularities in the low‐latitude F region is dominated by the morphology of bubbles at night and the ionospheric fountain process on the dayside. The seasonal and longitudinal distributions of daytime and nighttime irregularities in low latitudes are similar Zonal wave number 4 patterns in daytime irregularity distribution, plasma density, and vertical velocity show similar behavior The morphology of daytime irregularities is determined by the morphology of bubbles at night and fountain process on the dayside