| 项目编号: | 1452605
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| 项目名称: | Ground Level Measurements of Terrestrial Gamma Flashes |
| 作者: | Michael Cherry
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| 承担单位: | Louisiana State University & Agricultural and Mechanical College
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| 批准年: | 2014
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| 开始日期: | 2015-04-15
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| 结束日期: | 2018-03-31
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| 资助金额: | USD300000
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| 资助来源: | US-NSF
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| 项目类别: | Continuing grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Atmospheric and Geospace Sciences
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| 英文关键词: | gamma ray
; tgf
; tetra-ii
; puerto rico
; lightning
; lsu
; ground-level
; jamaica
; high energy level
; cloud-to-ground lightning
; student
; ground-level tgf
; terrestrial gamma flashes
; ground-level observation
|
| 英文摘要: | Satellite observations of intense millisecond flashes of gamma rays (Terrestrial Gamma Flashes - TGFs) produced at the tops of thunderstorms have shown that lightning can accelerate electrons to very high energy levels, well above 100 million electron volts (MeV). A recent experiment at Louisiana State University (LSU) has now shown that TGFs are produced by lightning near the Earth's surface, and that the gamma ray intensity at the source is extremely high. The TGF and Energetic Thunderstorm Rooftop Array (TETRA) at LSU shows the existence of ground-level TGFs associated with nearby lightning. This project is a follow-up experiment, TETRA-II, intended to measure the energy and intensity spectrum with improved statistics, extend the energy range, determine the height at which TGFs are produced, and provide for the first time correlated radiation and meteorological data. TETRA-II will be located at two sites in Puerto Rico and Jamaica, at locations where thunderstorm activity is significantly higher than at the current TETRA site in Louisiana and where satellite overflights will enable looking for TGFs simultaneously from the ground and from space.
Intellectual Merit:
Satellite observations of TGFs have shown the connection between the gamma rays and lightning. Typically, though, it is difficult to associate the gamma ray events with individual well-localized thunderstorms. The ground-level observations reported by TETRA have made it possible to associate the gamma rays with lightning within 3 miles or closer to the detectors, and have made it possible to begin to study the correlations with detailed radar images of the thunderstorms. TETRA-II will be located in a region chosen to have high lightning density and a high frequency of TGFs seen by orbiting gamma ray satellites; it will be designed to have a factor of 5 better statistics than TETRA for individual events and a higher energy range (up to 10 MeV) so that measurements can be compared to model predictions; and it will be operated in conjunction with both a local array of low frequency (LF, ~100 kHz) lightning detectors and broadband global and regional networks capable of observing intra-cloud in addition to cloud-to-ground lightning, together with nearby radar. As a result, TETRA-II is expected to provide unique and detailed new data about TGFs observed close to lightning, providing new information both about the production mechanisms of the high energy radiation and about the connection with the lightning events.
Broader Impacts:
TETRA-II will be built and operated largely by a student team. Equipment funds have been provided by the Louisiana Board of Regents, with the equipment construction to be performed by students from LSU and two nearby HBCUs (Southern University in Baton Rouge and Xavier University in New Orleans). LSU staff will do the primary design, train and supervise the students, and oversee the construction. At the same time, an array of low frequency lightning detectors will be deployed and operated by the student teams in Puerto Rico and Jamaica in order to make final determinations of the sites, explore remote operations at the two sites, gain experience with the lightning detection, and organize the Puerto Rico and Jamaica teams to be able to perform continued maintenance and operation of the detectors in the field. After a year of initial detector construction and testing by the students in Louisiana, the detector array will be deployed during the summer of 2015. The array will be operated remotely and the data analysis led from Louisiana, with contributions from the student teams in Puerto Rico and Jamaica.
Initial results are expected by the fall of 2015. A goal will be to use TETRA-II to provide research opportunities for students from LSU, Southern, Xavier, Univ. of Puerto Rico, and Univ. of the West Indies in Jamaica for at least 5-10 years. The experiment will also contribute to the development of research capability in Puerto Rico and a developing nation in the Caribbean (Jamaica). This NSF support is intended to provide operating funds for LSU and the Univ. of Puerto Rico at Bayamon. The Jamaica collaborators will request independent funding from US-AID. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/94852
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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| Recommended Citation: | |
Michael Cherry. Ground Level Measurements of Terrestrial Gamma Flashes. 2014-01-01.
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