论文标题
脉冲极光期间的斑块尺寸演变
Patch Size Evolution During Pulsating Aurora
论文作者
论文摘要
我们报告了脉动极光事件期间斑块大小的趋势下降和增加的趋势。在Fennoscandian Lapland上大约有150个脉动的极光事件已成功地分析了其平均斑块大小，总斑块面积和斑块数量，这是事件时间的函数，通常为1-2 hr。已经开发了一个自动例程来检测全天空相机图像中的补丁。除了在脉动极光过程中随着平均斑块大小的减少和增加的事件外，还发现了没有大小趋势和事件的事件随着间歇性增加和减小的斑块大小趋势的事件。在这项研究中，我们分析了一部分事件，该事件的平均斑块和总斑块大小会系统地增加或减小。随着斑块大小趋势增加的事件不会降低峰值发射高度，这与脉动极光沉淀的行为有关。此外，斑块大小增加的事件具有较短的寿命，并且在地球同步轨道处的实量注入能量电子的两倍，而斑块大小的事件则是斑块尺寸减少的事件。在质量扩张阶段中，有一半的斑块大小增加的事件发生，而在恢复阶段，大多数（64％）的斑块大小减少的事件发生。这些发现表明，脉动极光的视觉外观可以用作脉动极光能量沉积到大气中的指示。
We report both decreasing and increasing trends in the patch sizes during pulsating aurora events. About 150 pulsating auroral events over the Fennoscandian Lapland have been successfully analyzed for their average patch size, total patch area, and number of patches as a function of event time, typically 1-2 hr. An automatic routine has been developed to detect patches in the all-sky camera images. In addition to events with decreasing and increasing average patch size evolution over the course of the pulsating aurora, events with no size trends and events with intermittently increasing and decreasing patch size trends were also found. In this study, we have analyzed a subset of events for which the average and total patch size systematically increase or decrease. The events with increasing patch size trend do not experience a decrease in the peak emission height, which was previously associated with the behavior of pulsating aurora precipitation. Furthermore, the events with increasing patch sizes have shorter lifetimes and twice as many substorm-injected energetic electrons at geosynchronous orbit as the events with decreasing patch sizes. Half of the events with increasing patch sizes occur during substorm expansion phases, while a majority (64%) of the ones with decreasing patch sizes take place during the recovery phase. These findings suggest that the visual appearance of pulsating aurora may be used as an indication of the pulsating aurora energy deposition to the atmosphere.
