Some ubiquitous features of the mesospheric Fe and Na layer borders from simultaneous and common‐volume Fe and Na lidar observations
Some ubiquitous features of the mesospheric Fe and Na layer borders from simultaneous and common‐volume Fe and Na lidar observations
复制标题
DOI：
10.1029/2007ja012632
复制
发表时间：
2008-04
影响因子：
--
通讯作者：
F. Yi;Shaodong Zhang;X. Yue;He Yujin;Yu Changming;Chunming Huang;Wei Li
中科院分区：
文献类型：
--
作者：
F. Yi;Shaodong Zhang;X. Yue;He Yujin;Yu Changming;Chunming Huang;Wei Li
[1] 通过在中国武汉（北纬 30.5°，东经 114.4°）同步共体积铁和钠激光雷达测量获得的高精度原子密度剖面，揭示了铁和钠层边界上的一些普遍特征。 Fe和Na下界始终表现出微妙的层结，其中Fe层下界总体略高于Na层下界或重合，总体平均高差约为0.2 km。尽管存在相当大的垂直位移，两个下边界总是沿着几乎相同的轨道变化。两者总体相关系数高达0.96。这种普遍存在的测量下边界的微妙分层（几乎重合的密度截止）强烈表明，Fe 和 Na 层的底面是由相同或非常相似的过程控制的。 Na层的上边界总是比Fe层的上边界高几公里。在两个上限之间也持续观察到相对较弱的正相关性。弱的零星分层事件经常发生在金属层的上部范围。它们可能会损害正常金属层上边界的正确确定，从而削弱相关性。 Fe层和Na层的下侧密度梯度通常明显大于上侧的密度梯度，并且Fe层的边界明显比Na层的边界更陡。对这些普遍特征的解释需要进一步的实验和建模工作。
[1] High-accuracy atom density profiles, obtained by the simultaneous and common-volume Fe and Na lidar measurements at Wuhan, China (30.5°N, 114.4°E), reveal some ubiquitous features of the Fe and Na layers on their borders. The Fe and Na lower boundaries show consistently a delicate stratification in which the lower boundary of the Fe layer is in general slightly higher than or coincident with that of the Na layer, with an overall mean altitude difference being about 0.2 km. Despite the existence of considerable vertical displacements, the two lower boundaries vary always following almost the same track. The overall correlation coefficient between them is as high as 0.96. This ubiquitous delicate stratification of the measured lower boundaries (nearly coincident density cutoff) suggests strongly that the undersides of Fe and Na layers are controlled by the same or very similar processes. The upper boundary of the Na layer is always several kilometers higher than that of the Fe layer. A relatively weak positive correlation is also persistently observed between the two upper boundaries. Weak sporadic layering events frequently occur on the upper extent of the metal layers. They may impair the correct determination of the upper boundaries of the normal metal layers and consequently weaken the correlation. Both the Fe and Na layers often show an evidently steeper density gradient on the underside than on the upper extent, and the borders of the Fe layer are clearly steeper than those of the Na layer. The explanation to these ubiquitous features needs further experimental and modeling efforts.