Revisiting "Narrow Bipolar Event" intracloud lightning using the FORTE satellite
Revisiting "Narrow Bipolar Event" intracloud lightning using the FORTE satellite
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DOI：
10.5194/angeo-30-389-2012
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发表时间：
2012-01-01
影响因子：
1.9
通讯作者：
Light, T. E. L.
中科院分区：
文献类型：
--
作者：
Jacobson, A. R.;Light, T. E. L.
雷击称为“窄双极事件”，或NBE，是一种云内放电，负责显着的电荷重新分布。NBE发生在1020 μ s内，一些相关的过程发出强烈的无线电噪声的不规则突发，在较短的时间尺度衰落，偶尔在电荷转移。在以前的报告中，NBE被推断为与其他形式的雷击有很大的不同，在两个方面：首先，NBE被推断为与其他雷击相比相对较暗（不发光）。其次，NBE被推断为孤立在风暴中，通常不参与闪电，但当它处于闪电中时，NBE被推断为闪电引发者。这两个推论对NBE物理学有足够明显的影响，它们应该受到进一步的独立检验，改进统计。我们尝试这样一个测试与光学和无线电数据从FORTE卫星，并与雷击数据从洛斯阿拉莫斯Sferic Array.We严格表明，由触发PDD光学光度计上的FORTE卫星的度量，NBE放电确实不如普通的闪电发光。参考云顶的有效各向同性发射器，NBE光输出被推断为小于类似于3 × 10（8）W。为了解决NBE的隔离问题，我们首先通过从相同闪光或相同风暴的其他记录中借用地理位置来扩展地理定位的云内无线电记录池。通过这种方式，我们生成了一个类似于2 x 10（5）个独特和独立的FORTE云内无线电记录的池，可以推断出其与卫星的倾斜距离。然后，我们使用这个斜程计算在无线电源的有效辐射功率（ERP），在通带26-49 MHz。分层的无线电录音ERP到八个箱子，从最低的bin（140千瓦），我们记录的趋势，无线电录音变得更加孤立的时间ERP的增加。最高的ERP箱对应于与NBE相关联的云内发射。在最高的ERP，时间邻居的唯一显着的概率是在高ERP事件之后的时间。换句话说，当参与闪光时，高ERP发射发生在明显的闪光开始时。
The lightning stroke called a "Narrow Bipolar Event", or NBE, is an intracloud discharge responsible for significant charge redistribution. The NBE occurs within 1020 mu s, and some associated process emits irregular bursts of intense radio noise, fading at shorter timescales, sporadically during the charge transfer. In previous reports, the NBE has been inferred to be quite different from other forms of lightning strokes, in two ways: First, the NBE has been inferred to be relatively dark (non-luminous) compared to other lightning strokes. Second, the NBE has been inferred to be isolated within the storm, usually not participating in flashes, but when it is in a flash, the NBE has been inferred to be the flash initiator. These two inferences have sufficiently stark implications for NBE physics that they should be subjected to further independent test, with improved statistics. We attempt such a test with both optical and radio data from the FORTE satellite, and with lightning-stroke data from the Los Alamos Sferic Array.We show rigorously that by the metric of triggering the PDD optical photometer aboard the FORTE satellite, NBE discharges are indeed less luminous than ordinary lightning. Referred to an effective isotropic emitter at the cloud top, NBE light output is inferred to be less than similar to 3 x 10(8) W.To address isolation of NBEs, we first expand the pool of geolocated intracloud radio recordings, by borrowing geolocations from either the same flash's or the same storm's other recordings. In this manner we generate a pool of similar to 2 x 10(5) unique and independent FORTE intracloud radio recordings, whose slant range from the satellite can be inferred. We then use this slant range to calculate the Effective Radiated Power (ERP) at the radio source, in the passband 26-49 MHz. Stratifying the radio recordings by ERP into eight bins, from a lowest bin (140 kW), we document a trend for the radio recordings to become more isolated in time as the ERP increases. The highest ERP bin corresponds to the intracloud emissions associated with NBEs. At the highest ERP, the only significant probability of temporal neighbors is during times following the high-ERP events. In other words, when participating in a flash, the high-ERP emissions occur at the apparent flash initiation.