A review of latitudinal characteristics of sporadic sodium layers, including new results from the Chinese Meridian Project
A review of latitudinal characteristics of sporadic sodium layers, including new results from the Chinese Meridian Project
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零星钠层的纬度特征综述，包括中国子午线计划的新结果
DOI：
10.1016/j.earscirev.2016.07.004
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发表时间：
2016-11
影响因子：
12.1
通讯作者：
Wang, Yuhong
中科院分区：
文献类型：
--
作者：
Xue, Xianghui;Dou, Xiankang;Li, Tao;Wang, Yuhong
本文总结了不同纬度和不同高度的零星钠层（SSLs或NaS）的特征，并讨论了可能的机制。在高纬度地区，SSLs在午夜附近有一个最大的频率，在以前的研究中报道了显着的高度和强度的季节差异。夏季小卫星的平均高度远低于冬季小卫星，夏季小卫星的平均密度增强因子远大于冬季小卫星。对SSLs和零星E层（ES）的同时观测表明，ES可能对高纬SSLs的形成有重要贡献。温度机制对高纬度卫星固体激光的贡献很小，特别是在最低温度条件下观测到大量或频繁的高纬度卫星固体激光，在20°N ~ 35°N的亚热带地区，不同站的卫星固体激光具有相似的特征。合肥（31.8°N，117.3°E）的SSL爆发维持在（？）20 ~ 03 LT出现高峰，峰高分布夏、冬两季有明显差异。冬季零星钠事件主要局限于96 km以下的高度，而夏季SSLs经常发生在96 km以上。同时观测到的SSLs、ESs和高温表明，亚热带地区SSLs与高温条件的关系比与ESs的形成关系更密切。高温很可能是由重力波破碎引起的，再加上新提出的冰尘钠库，这两个过程可能对副热带SSLs的形成有重要贡献。相反，在副热带地区，大部分的卫星地面环流并不受地球同步辐射的影响，只有少数96 km以上的卫星地面环流受地球同步辐射的影响，特别是在夏季的5 ~ 8月。海口站（19.5°N，109.1°E）的观测结果表明，低纬卫星地面环流与副热带地区的卫星地面环流有相似的特征。海口地区的沙尘暴在20 ~ 03 LT之间也有稳定的发生频率，冬季沙尘暴的平均海拔低于夏季。而96 km以上的卫星同步辐射的出现频率没有明显的季节差异。低纬台站的大量观测资料表明，低纬地区的SSLs可能是由温度控制机制和ES理论共同作用的结果，而且每种机制都能产生不同类型的SSLs。温度控制机制更可能解释96 km以下的大型SSL，而ES理论可能对96 km以上的SSL有更直接的贡献。我们的结果突出了温度机制和ES理论对不同纬度和高度SSL形成的单一机制和联合作用。高纬SSLs与ES理论的联系更紧密，副热带SSLs与高温的相关性更强，而温度机制和ES理论对低纬海口站SSLs的贡献可能相当。事实上，我们表明，在海口的观测产生的例子，两个SSL事件可以由不同的机制控制，即使它们发生在同一地点在同一个晚上。
Characteristics of the sporadic sodium layers (SSLs or NaS) in different latitudes and altitudes are summarized in this paper and the possible mechanisms are discussed. The SSLs in high latitude have a maximum frequency near midnight with significant seasonal differences of height and intensity being reported in previous studies. The average height of summer SSLs was much lower than that of winter SSLs and the average density enhancement factor for summer SSLs was much larger than that for winter SSLs. The simultaneous observations of the SSLs and sporadic E layers (ES) suggested that the ESprobably contribute significantly to the formation of high latitude SSLs. In contrast, the temperature mechanism seemed to contribute little to the high latitude SSLs, especially since plenty or frequent high latitude SSLs were observed under minimum temperature conditions.The SSLs in the subtropical area from 20°N to 35°N show similar characteristics between different stations. The onset of SSLs in Hefei (31.8°N, 117.3°E) maintains (?) high occurrence from 20 to 03 LT and the peak height distribution is distinctly different between summer and winter. The winter sporadic sodium events are largely confined to altitudes below 96 km, while summer SSLs occurred frequently above 96 km. The simultaneous observations of SSLs, ESand high temperature suggested that the SSLs in subtropical area have a closer link with high temperature conditions than with the formation of ES. The high temperature are most likely caused by gravity wave breaking, together with a newly proposed icy dust sodium reservoir, both processes probably contribute importantly for the formation of subtropical SSLs. In contrast, the ESare not essential for most SSLs in the subtropical area, and they seem to influence only a few SSLs above 96 km, especially in the summer months from May to August.The observations from the Haikou station (19.5°N, 109.1°E) suggested that the SSLs in low latitude have some similar characteristics with that of the subtropical area. SSLs in Haikou also have stable occurrence frequency between 20 and 03 LT and the average altitude of the winter SSLs is lower than that of the summer SSLs. However, the occurrence frequency of SSLs above 96 km does not show any obvious seasonal difference for this station. The abundance of data and observations from low-latitude stations indicate that both the temperature control mechanism and EStheory are likely responsible for the formation of SSLs in the low latitudes and each mechanism can generate distinct types of SSLs. Temperature control mechanism is more likely to account for the large SSLs below 96 km, while EStheory probably contributes more directly to some SSLs above 96 km.Our results highlighted both the single-mechanism and combined actions of the temperature mechanism and EStheory on the formation of the SSLs in different latitudes and altitudes. The high latitude SSLs have a closer link with the EStheory and the subtropical SSLs correlate more strongly to high temperature, while both the temperature mechanism and EStheory probably contribute equally to the SSLs in the low-latitude Haikou station. In fact, we show that the observations in Haikou yield the example that two SSL events could be controlled by different mechanisms even though they occurred at the same location within the same night.
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DOI：
10.1016/0021-9169(89)90077-9
发表时间：
1989-04
影响因子：
1.9
作者：
S. Kirkwood;P. Collis
通讯作者：
S. Kirkwood;P. Collis
影响因子：
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作者：
R. Hake;D. E. Arnold;D. Jackson;W. Evans;B. Ficklin;R. L. Long
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R. Hake;D. E. Arnold;D. Jackson;W. Evans;B. Ficklin;R. L. Long
影响因子：
2.6
作者：
B. Clemesha
通讯作者：
B. Clemesha
影响因子：
4.4
作者：
Clemesha, BR;Batista, PP;Batista, IS
通讯作者：
Batista, IS
DOI：
10.1046/j.1365-8711.2001.04703.x
发表时间：
2001-12-21
影响因子：
4.8
作者：
Michaille, L;Clifford, JB;Wooder, NJ
通讯作者：
Wooder, NJ