太阳静日变化的特征分析          下载免费PDF全文

赵德军  徐新强  段金梅 《海洋测绘》2012,32(6):24-26

根据北京明陵地磁台2010年观测数据,采用磁静日数据,选用其特征值——日变幅度和相位,对太阳静日变化特征进行了初步分析,并用调和分析方法将其分解为3个周期的谐波分量。对地磁数据的分析处理具有一定的参考价值。  相似文献   

蒙城地震台地磁Z分量日变化特征分析     

曹志磊  周琼  张有林  汪继林  薛志明  郎孝龄 《地震地磁观测与研究》2008,29(5):48-51

利用蒙城地震台近20年的地磁Z分量观测资料，对磁静日幅度、磁扰日幅度和磁静日低点时间的年变化与长期变化进行了分析，结果表明，Z分量日变化特征明显。由此总结出Z分量变化的一些基本特征，对识别地磁场异常变化或干扰变化具有一定的参考价值。  相似文献   

中国大陆及华北地区地震资料的小波分析   总被引：15，自引：8，他引：7  

万永革  齐福荣  孟晓春  庄献华 《大地测量与地球动力学》2003,23(4):28-33

基于地震活动为多尺度多活动这一观点，运用小波变换方法，以不同的小波尺度分析了中国大陆1900～2001年和华北地区1500～2001年M≥5地震的本尼奥夫应变资料，得到了各种层次地震活跃期和平静期，分析结果可信而又符合实际。对历史地震研究和地震危险性预测具有一定的参考价值。  相似文献   

Creative democracy and the quiet politics of the everyday     

Katherine Hankins 《Urban geography》2017,38(4):502-506

John Dewey envisioned creative democracy as a process of agonistic engagement, and Bob Lake shares Dewey’s optimism for the possibilities of creative democracy. In this response, I suggest that scholars should look beyond the obvious moments of democratic political engagement, whether activism in the public square or in the occupied park, to pay attention to the quiet politics of the everyday, where everyday decisionmaking by individuals and communities can gradually, episodically, change dominant hegemonic norms and understandings, proviing new understandings for social change. I highlight several examples, including the Settlement house movement from the late 19th century and intentional neighboring from the twenty-first century, that illustrate the kind of daily work that brings together different social classes and ethnicities in a situation of sharing and working toward conditions of equality and new ways of living in the world.  相似文献   

Sub-Alfvénic flows in the quiet and recurrent solar winds     

Gong-liang Zhang 《Chinese Astronomy and Astrophysics》1996,20(4):482-486

Observed instances are given in this paper to show that sub-Alfvénic flow can be formed in the quiet and recurrent low-speed solar wind streams. This kind of flow appears in regions with abnormal enhancement of Alfvénic speed and is associated with a specific type of magnetic configuration.  相似文献   

First results from the Gauribidanur Radio heliograph     

K. R. Subramanian  R. Ramesh  M. S. Sundara Rajan  Ch. V. Sastry 《Astrophysics and Space Science》1996,243(1):259-262

Observations of the Sun at two frequencies (51 and 77 MHz) using the East-West arm of the Gauribidanur Radio heliograph are presented.  相似文献   

Sq的经度效应     

陈伯舫 《地震地磁观测与研究》1993,14(3):44-47

本文提供了一个事实:同纬度不同经度台站的S_q曲线可以有很大的差异。对拉萨台的S_q异常作了一些初步的、定性的分析与解释。对八丈台的S_q异常则认为难以解释,值得深入研究。  相似文献   

华北地区大震前区域地震活动的中短期变化          下载免费PDF全文

林怀存  刘希强 《地震地质》1997,19(1):38-42

对发生在华北地区３１个Ｍ≥５地震震前区域地震活动的时间序列进行的研究得出：（１）华北地区发生Ｍ≥５地震前，区域地震活动的短期平静现象与大震发生的相关性很强。３１个Ｍ≥５地震前的平静时间主要集中在２０～８７ｄ，１２０～２１０ｄ和大于２１０ｄ。同时还得出大震前的短期平静时间与震级大小无关的结论；（２）区域地震活动在短时间内出现增强趋势，与发生大震的相关性很弱，相关的仅占总数的６．４％  相似文献   

Very quiet intervals of geomagnetic activity and the solar wind structure     

Jaroslava Hruska  Antonin Hruska 《Pure and Applied Geophysics》1989,131(3):343-355

Extended periods of very low geomagnetic activity as described by very quiet intervals (VQI's) occur only at those times when the solar wind velocityV has a generally decreasing trend, i.e., they mainly occur either after the velocity peak of a high speed solar stream has passed the Earth, or at times when the Earth is immersed in a low speed solar plasma provided that the daily mean value ofdV/dt is negative. The VQI's most frequently start whendV/dt<0 anddB _Z/dt>0 (B _Z is the geocentric solar magnetrospheric-GSMZ-component of the IMF) and end most likely whendV/dt>0 anddB _Z/dt<0. The temporal trends of the solar wind (SW) velocity affect the variation of thea _p index only when the level of geomagnetic activity is generally low.It is suggested that a gradual expansion or contraction of the magnetosphere, associated with a slow variation of the SW pressure, plays a role in the modification of the reconnection-driven magnetohydrodynamic (MHD) fluctuations in the magnetosphere.  相似文献   

AbnormalSq behaviour     

E. C. Butcher 《Pure and Applied Geophysics》1989,131(3):463-483

It is well-known that the amplitude and phase of theSq(H) variation show considerable variability from day to day. In this paper we consider one aspect of the phase variability—that associated with AQDs. AQDs (or abnormal quiet days) are defined as magnetically quiet days where the maximum excursion ofH at a mid-latitude station on the poleward side of the focus occurs outside the normal time range 0830–1330 LST. Such days exhibit properties, many of which appear quite distinct from the properties of the normalSq(H) variation. The properties of AQDs, and the proposals that have been made to explain them, are considered in detail. The consequences of these proposals and some problems which need to be addressed in order to obtain a fuller understanding of the dynamics of the ionosphere on AQDs are also discussed.  相似文献