Study of ionospheric E- and F-region irregularities generated by atmospheric gravity waves

大气重力波产生的电离层E区和F区不规则性的研究

基本信息

批准号：
07454117
负责人：
FUKAO Shoichiro
金额：
$ 4.99万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07454117/
关键词：
Field-Aligned Irregularity Mid-Latitude Ionosphere Spradic-E layr Perkins Instability Atmospheric gravity wave MU radar SEEK project Rocket Ground-based Observation

项目摘要

Recent research has shown that field-aligned irregularities (FAI) in the ionosphere are active in the midlatitude E-and F-regions, and have wavelike structures associated with atmospheric gravity waves. Purpose of this study was to observe the midlatitude FAI in both E-and F-regions with the MU radar and other facilities, and reveal their generation mechanism. The period of this study (1995-1997) well coincided with the solar minimum condition, which was considered to be active period of the F-region FAI.In this period, the project of SEEK (Sporadic-E Experiment over Kyushu), a rocket / radar coordinated observation campaign for the E-region FAI,was also conducted. We participated in the SEEK campaign, and operated the frequency agile radar (FAR) of SRI International with Communications Research Laboratory in Tanegashima Space Center of National Space Development Agency. The FAR observations were conducted during August-October 1995 and during July-September 1996.From this study, especially from the SEEK campaign, we found that there existed unexpectedly large polarization electric fields of 10-20 mV / m in the E-region FAI.Neutral wind velocity observed with the chemical release experiment from a rocket showed very large vertical shear that could generate the Kelvin-Helmholtz instability in the background atmosphere. These results from the SEEK campaign will be published as 14 papers in a special issue of the Geophysical Research Letter. For the F-region FAI we found 100km-scale wavelike structures that resembles those of the Perkins instability. We found smaller structures with wavelengths of several tens of kilometers as well. From ten-years of F-region FAI observations with the MU radar, we could confirm that activity of the F-region FAI shows clear anti-correlation to the solar activity.

最近的研究表明，电离层中与现场对齐的不规则性（FAI）在中纬度和F区中具有活性，并且具有与大气重力波相关的波浪结构。这项研究的目的是观察E-and F-Readar和其他设施的E F区域中的纬度FAI，并揭示其产生机制。这项研究（1995-1997）的期间与太阳最小条件息息相关，太阳最小条件被认为是F-Region Fai的活跃时期。在此期间，Seek的项目（对Kyushu上的零星 /雷达雷达协调的观察活动）是针对E-Gregion Fai的火箭 /雷达协调的观察活动。我们参加了SEEK运动，并在国家空间发展局Tanegashima空间中心的通信研究实验室经营了SRI International的频率敏捷雷达（FAR）。远距离观察是在1995年8月至10月的1996年10月进行的。从这项研究，尤其是从寻求运动中，我们发现，在e-Region fai中存在意外的较大的极化电场，在e-Region fai中，在不中性风速中，从火箭上表现出很大的垂直频率，可以在keel shear的稳定性中观察到kele shear的稳定性。 Seek运动的这些结果将在《地球物理研究信》的特刊中作为14篇论文发表。对于F-Region FAI，我们发现了100公里尺度的波浪结构，类似于珀金斯不稳定性。我们发现了较小的结构，其波长也有数十公里。从使用MU雷达的F-Region Fai观测值十年来，我们可以确认F-Region FAI的活性表现出与太阳能活性的明显抗相关性。