Investigation of Spatiotemporal Morphology of Plasma Bubbles Based on EAR Observations
Investigation of Spatiotemporal Morphology of Plasma Bubbles Based on EAR Observations
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DOI：
10.1029/2019ja026839
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发表时间：
2019-12
期刊：
影响因子：
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通讯作者：
L. Joshi;L. Tsai;S. Su;Y. Otsuka;T. Yokoyama;M. Yamamoto;S. Sarkhel;K. Hozumi;C.‐H. Lu
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文献类型：
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作者：
L. Joshi;L. Tsai;S. Su;Y. Otsuka;T. Yokoyama;M. Yamamoto;S. Sarkhel;K. Hozumi;C.‐H. Lu
利用Kototabang赤道大气雷达扇形观测资料，研究了赤道等离子体泡（EPB）的时空特征。EPB的特点是本地生成的（其成因和随后的演变在扇扇形图中观察到）或漂移型（从西方漂移到扇扇形扫描）。雷达回波谱宽的研究表明，漂移的土压平衡可能是不太进化的类型。在Kototabang和春蓬的日落后期间的F层的高度进行了检查，在这两种类型。本地产生的EPB病例的平均峰值h′F高于漂移EPB病例（约25 km），这也具有统计学显著性。这种情况已经在一个大尺度驻波结构（LSWS）方面进行了可视化，其相位决定了EPB是否会在赤道上演变或从西经漂移。此外，还检查了两种情况下的低纬度零星E（Es）变异。Es与峰值h′F（取决于LSWS的波峰/波谷）成反比关系。这些结果已经讨论了早期的工作在EPB集群的空间形态，特别是在上下文中的LSWS的可能产生机制的空间不均匀性在低纬E区的导电性。在本地产生的EPB情况下，低纬度Es的出现较少，这也表明E区电导率对瑞利-泰勒不稳定性的重要作用。这些结果强调了对低纬度Es进行网络化空间观测的必要性。
Spatiotemporal characteristics of equatorial plasma bubble (EPB) have been studied based on Equatorial Atmosphere Radar (EAR) fan sector observations from Kototabang. EPBs were characterized as either locally generated (whose genesis and subsequent evolution was observed in the fan sector maps) or drifted type (which drifted into fan sector scans from west). Investigation of the radar echo spectral width indicated that the drifted EPB could be less evolving type. Height of the F layer in the postsunset period over Kototabang and Chumphon were examined in the two types. Average peak h′F was higher in locally generated EPB cases than in drifted EPB cases (by ~25 km), which is also found to be statistically significant. This scenario has been visualized in terms of a standing large‐scale wave structure (LSWS) whose phase determine whether EPB will be seen evolving over EAR or drifted from a western longitude. Furthermore, low‐latitude sporadic E (Es) variabilities in the two cases were also examined. Es indicated an inverse relation with the peak h′F (which depends on crest/trough of LSWS). These results have been discussed in the light of earlier works on spatial morphology of EPB clusters, particularly in context to the possible generation mechanism of LSWS by the spatial inhomogeneity in the low‐latitude E region conductivity. Lesser occurrence of low‐latitude Es in locally generated EPB cases also signifies the vital role of E region conductivity on Rayleigh‐Taylor instability. These results highlight a need for networked spatial observation of low‐latitude Es.