Equatorial bubbles observed at the north and south anomaly crests: Dependence on season, local time, and dip latitude
Equatorial bubbles observed at the north and south anomaly crests: Dependence on season, local time, and dip latitude
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DOI：
10.1029/97rs00285
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发表时间：
1997-07
期刊：
影响因子：
1.6
通讯作者：
J. Whalen
中科院分区：
文献类型：
--
作者：
J. Whalen
赤道气泡，这会导致闪烁，破坏transonospheric RF传播，是很难研究的，因为它们是不可预测的，非常多变。这项工作的目的是利用在西半球阿普尔顿异常峰南北两个地点运行的电离层探测器，在太阳活动最大期全年进行连续观测，对这些现象进行研究。在这里，在一个广泛的案例研究中的直接观察发现，当气泡通过阿普尔顿异常峰附近的测深仪时，可以通过范围扩展F（RSF）的出现来识别气泡，范围扩展F（RSF）非常严重，以至于无法评估ANOF2。利用这种模糊扩散F作为标记，在37天内，由三个异常测深仪在北纬16°和20.3°以及南纬19.9°的倾角纬度上记录了104次气泡，并将其记录在每小时的表中。在每个位置，发生是最大的春分点附近，零在7月，最小在12月，最大之间2200和2400 LT的签名的解释是支持其一致性在两个季节和当地时间与其他人观察到的气泡。总的来说，在16°和20°倾角纬度之间，出现率降低了0.38倍，显然是关于倾角赤道对称的。而RSF在异常总是由气泡，RSF在赤道没有，最明显的时期是接近12月时，气泡有一个最小值，但赤道RSF有一个最大值，几乎每天都发生在日落后。这种非气泡赤道RSF显然是由底侧扩展F引起的。
Equatorial bubbles, which cause scintillation that disrupts transionospheric RF propagation, are difficult to study because they are unpredictable and extremely variable. This work undertakes to study them by continuous observation throughout a year at solar maximum using ionospheric sounders operating at sites in the western hemisphere in both north and south Appleton anomaly crests. Here direct observation in an extensive case study has found that bubbles can be identified when passing over a sounder near the Appleton anomaly crest by the appearance of range spread F (RSF) that is so severe that it prevents evaluation of ƒoF2. Using this obscuring spread F as a signature, bubbles are recorded in the hourly tabulations of ƒoF2 on 37 days a total of 104 times by three anomaly sounders at dip latitudes of 16° and 20.3° in the north and 19.9° in the south. At each location, occurrence is maximum near the equinoxes, zero in July with a minimum in December, and maximum between 2200 and 2400 LT. Interpretation of the signature is supported by its consistency in both season and local time with bubbles observed by others. Overall, occurrence decreases by a factor of 0.38 between 16° and 20° dip latitude, apparently symmetrically about the dip equator. Whereas RSF at the anomaly always results from bubbles, RSF at the equator does not, the most evident period being near December when bubbles have a minimum but equatorial RSF has a maximum, occurring nearly every day following sunset. This nonbubble equatorial RSF apparently results from bottomside spread F.