利用GPS数据研究江西区域电离层对台风“潭美”的响应

以2013年8月22日途经江西的台风"潭美"为研究背景,利用江西连续运行参考站(CORS)获取的GPS数据反演高精度TEC,对台风"潭美"登陆前后多天电离层的TEC进行了分析,发现:8月22日电离层TEC变化存在异常,且在台风登陆前TEC变化在逐渐增大,台风过境后TEC变化值出现下降趋势;进一步对台风登陆前后一段时间的TEC时间序列进行谱分析后,认为8月22日电离层TEC的扰动很可能与台风有关;对台风当天即8月22日各站点进行时间序列和空间强度分析,结果表明距离台风路径越远,TEC的扰动强度越小。进一步确认8月22日的电离层异常与台风具有相关性。     

Structural analysis of information digitization on process of Dujiangyan area in Sichuan earthquake(Ms 5.0)

This paper attempts to analyze geothermy revealed by the sounding data at 8 h and 20 h every day from China Meteorological Administration and the data counted per minute such as the wellhead temperature,the electromagnetic disturbance,the ground tilt and so of water level instrument in Sanxing of Chengdu with the method of information digitization.The result shows the recognizable differentiation of the change process before and after the earthquake,provides an analytic method for the improvement of earthquake prediction or prevention,and shows the feasible further research and the wide application prospect.     

基于时频分析的高频地波雷达电离层杂波抑制

针对高频地波雷达回波信号中的电离层杂波,提出了利用时频分析与特征值分解抑制杂波的方法.该方法首先通过时频分析合理地选择扫频脉冲时段和多普勒频率区间;然后对选定的时频域区间,采用特征值梯度准则与相邻距离元插值估计相结合的方法,分别在阵元-脉冲域和阵元-多普勒域进行特征值分解,更好地抑制了电离层杂渡.实测数据处理结果表明,该方法对电离层杂波具有很好的抑制效果.     

Absorption events associated with solar flares

During the upward period of solar cycle 23, the Imaging Riometer at Zhongshan, Antarctica (geomag. lat. 74.5 S) was used to study the solar proton events and the Xray solar flares which are associated with the absorption events. In our study, the relationship between the absorption intensity and X-ray flux is found in a power form which is consistent with the theoretical result. The imaging riometer absorption data at Ny-Ålesund, Svalbard reconfirm the above relationship. We also argue that only M-class flares can generate a significant daytime absorption.     

基于短波段电离层探测数据分析地下核爆引起的电离层扰动

同GNSS（全球导航卫星系统,Global Navigation Satellite System）获取电离层TEC（总电子含量,Total Electron Content）数据相比,传统的电离层垂测、斜测等短波段数据具有特征参数丰富、高度分辨率高、历史数据多等优点。为利用电离层垂测和斜测数据,研究地下核爆引起的电离层扰动。本文利用2016年1月6日朝鲜地下核试验当天的斜测、垂测数据分析电离层扰动现象。结果表明,本次地下核爆造成的行波电离层扰动为小尺度电离层扰动,传播速度在150.3-158.7(m·s-1)之间。同时核爆发生后半小时在距离爆点421.4 km处,观测到foF2较月中值增加了0.7 MHz,较1月5日、1月7日在2:00 UTC（协调世界时,Coordinated Universal Time)的foF2（F2层临界频率,critical frequency of the F2 layer）增加了0.5 MHz,极有可能是地下核爆通过岩石圈-大气圈-电离层圈耦合机制造成电离层电子浓度增加。本文分析结果与其他文献资料非常吻合。由此可见,基于短波段电离层探测方式感知电离层扰动从而实现地下核爆炸事件的监测,是一种有效的核爆电离层效应监测手段,可与其他直接监测手段相印证,提高核爆事件监测能力。     

Radio wave propagation effects produced by chemical releases in the ionosphere

As an effective means to actively modify the ionosphere,chemical release can produce artificial ionospheric holes as a consequence of ionization depletion,which can greatly impact on radio wave propagation.In this paper,on the basis of the pre-study results on ionospheric disturbances produced by some representative chemical releases,the radio waves propagation effects of ionospheric holes that are produced by two different release species,water(H2O) and sulfur hexafluoride(SF6),had been investigated and simulated by the three-dimensional(3-D) numerical ray tracing.The results show that ① the appearance of various artificial ionospheric holes can lead to certain decrease of critical frequency in the ionosphere,and ② when the wave frequency exceeds the critical frequency,the rays should be multiple reflections or penetrate through the ionospheric hole and focus afterwards with the focus altitude elevated for higher frequencies.This work may provide the necessary theoretical support for chemical release experiments and the evaluation of radio wave propagation effects.     

实际纱条的片段间变异-长度曲线与纱条不匀结构的关系

本文应用电子计算机和乌斯特(Uster)纱线均匀度仪的适当组合,实测了正常纱、含周期不匀纱和牵伸不匀纱条的片段间变异——长度曲线(简称B(L)曲线),找出了实际纱条的B(L)曲线与纱条不匀结构的关系。又应用随机过程理论和傅立叶变换方法,推证了实际纱条的B(L)曲线与纱条细度变化的各波长分量之间的关系,从而把过去沿用的有关理想纱条的B(L)曲线的理论发展到对实际纱条B(L)曲线的理性认识。本文所采用的测试方法,可作为今后研究纱条不匀和仪器研制工作的借鉴。     

Solar activity effects of the ionosphere: A brief review

Solar radiation, which varies over multiple temporal scales, modulates remarkably the evolution of the ionosphere. The solar activity dependence of the ionosphere is a key and fundamental issue in ionospheric physics, providing information essential to understanding the variations in the ionosphere and its processes. Selected recent studies on solar activity effects of the ionosphere are briefly reviewed in this report. This report focuses on (1) observations of solar irradiance at X-ray and extreme ultraviolet wavelengths and the outstanding problems of solar proxies, in the view of ionospheric studies, (2) new findings and improved representations of the features of the solar activity dependence of ionospheric key parameters and the corresponding physical processes, (3) possible phenomena in the ionosphere under extremely high and low solar activity conditions that are unique, as indicated by historical solar datasets and the deep solar minimum of solar cycle 23/24, and (4) statistical studies and model simulations of the ionosphere response to solar flares. The above-mentioned studies provide new clues for comprehensively explaining basic processes in the ionosphere and improving the prediction capability of ionospheric models and related applications.     

短波随机不平顺对列车-板式无砟轨道-路基系统振动特性的影响

运用弹性系统动力学总势能不变原理及形成矩阵的"对号入座"法则,建立列车-板式无砟轨道-路基竖向振动方程组,分析列车高速运行时,短波随机不平顺对列车-板式无砟轨道-路系统振动特性的影响,并对不同种类随机不平顺对列车-板式无砟轨道-路基系统动力特性的影响进行对比研究.研究结果表明:短波随机不平顺对车体垂向加速度、路基竖向压应力影响很小,对扣件竖向压应力、轨道板及底座板弯曲应力有一定的影响,对轮轨垂向力、钢轨振动加速度、轨道板振动加速度、底座板振动加速度和CA砂浆压应力则有显著的影响,影响超过中长波随机不平顺.研究车体及路基动力特性时可以不考虑短波随机不平顺,研究无砟轨道各部件动力特性时,则应考虑短波随机不平顺.