Extremely low ionospheric peak altitudes in the polar hole region
Extremely low ionospheric peak altitudes in the polar hole region
复制标题
极洞区域电离层峰值高度极低
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
J. Grebowsky
中科院分区：
文献类型：
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作者：
R. Benson;J. Grebowsky
利用最新获得的ISIS 2数字电离层顶部测深仪资料推导出的垂直电子密度Ne剖面，研究了太阳活动极小期冬季极冠电离层内局地电离损耗的高度结构。被研究的区域被称为极洞-极光空区，位于当地时间午夜之后，靠近极光椭圆形的极地一侧。早期的调查有时发现该地区的Ne值非常低(下降到300公里附近的200厘米−3)。在本研究中，发现了纬向Ne的亏损，但如此低的Ne值(≈100 cm−3)仅在ISIS2海拔1400公里附近发现。在Ne贫乏地区，ISIS2以下的电离层峰值浓度基本保持不变(∼105 cm−3)，但峰值高度急剧下降至100公里附近。这些观测结合其他数据表明，F层峰的缺失在高纬度地区可能是经常发生的，并强调了在高纬度水平NE构造调查中了解垂直Ne分布的重要性。
Vertical electron density Ne profiles, deduced from newly available ISIS 2 digital ionospheric topside sounder data, are used to investigate the altitude structure of localized ionization depletions within the winter, nighttime polar cap ionosphere during solar minimum. The region investigated, called the polar hole‐auroral cavity region, is located just after midnight magnetic local time near the poleward side of the auroral oval. Earlier investigations had at times found very low Ne values in this region (down to 200 cm−3 near 300 km). In the present study, latitudinal Ne depletions were found, but such low Ne values (≈ 100 cm−3) were only found near the ISIS 2 altitude of 1400 km. The peak ionospheric concentration below ISIS 2 remained fairly constant (∼105 cm−3) across the Ne‐depleted region, but the altitude of the peak dropped dramatically to the vicinity of 100 km. The observations, in combination with other data, indicate that the absence of an F layer peak may be a frequent occurrence at high latitudes and stress the importance of a knowledge of the vertical Ne distribution in high‐latitude investigations of horizontal Ne structures.