1958年4月19日海南島日环食时臭氧层的变化

一、引言由研究日食时臭氧层的变化可以获得引起臭氧层生成及破坏的各种过程进行速度的資料.但在黄昏时研究这些过程則不甚适合. 遺憾的是过去使用光譜学方法研究日食时臭氧层情况的工作并不多. 如在1936年6月19日日食时,J.Kawabata在R.Sekiguti領导下曾用石英光譜仪得到了在第二次接触（食既）时臭氧的明显增加,可是很明显,有云的天气使他們不能够研究进一步的变化.B.斯文生（Svensson）在1954年6月30日日食时借助道勃生（Dobson）光譜光度計亦得到了在3100及3300埃两波长处光強比的改变,这与一般在食甚时臭氧层增加的理論相符.     

山西省地震局召开思想政治工作研讨会

口回钳-“-“”嘎酚瞩a 圈刁回回圃 全体会。《代表汀, 山西有地是3气忍坷广;c工汁 ＄7JI )::t～]fy — —一A-叫MMty J——_MM_”-/.一l。M。 ’i>。气表。人.学刁:-卜【一 ;J。9/I]…(…fZ})〕J〕sk《‘〕4(’R>’)。Z。(t‘;’\J4K/O‘15’)“D‘V/(《\tLZ LLOZ】【{二【d.Jh〔F-IIJU相似文献   

龙门山和青藏高原的隆起与2008年汶川(M=7.9)地震

龙门山山脉,即2008年5月12日汶川（M=7．9）毁灭性地震的发生地,界定了喜马拉雅造山带的东缘,并显现出比青藏高原任何地方都大的地形起伏。然而,在这次地震之前,大地测量与地质调查工作都没有测到横跨该山系前缘有明显的缩短变形（Shenetal,2005;Meade,2007;Chenetal,2000）,从而引起了关于该山岳带地形的形成与发展过程的激烈争论。现已提出两个端元模型：（1）脆性地壳增厚,即具有大量滑动的逆冲断层切穿岩石层并引起隆起（Ta—pponnieretal,2001）;（2）地壳流动,即青藏高原下地壳的低粘度物质向外挤出,抬升了喜马拉雅山东北部的地壳（Roydenetal,1997;Burehfiel,2004;Bird,1991）。在此,我们使用平衡地质剖面来说明该山系前缘的地壳缩短、构造起伏与地形地貌是密切相关的。这表明,地壳缩短是位于青藏高原东缘的龙门山的隆起及其地形形成的主要驱动力。致使沿该山系前缘大型逆冲断层发生破裂,并造成数万人死亡和大范围破坏的2008年汶川地震（M=7．9）就是这种地壳缩短过程的作用表现。     

大地震前发生的前震

在时间间隔超过20年的两份全球地震目录里，选取所记录的浅源M≥6和M≥7主震以及M≥5的前震，计算了前震的发生率。当把它们各自的震级差范围作了归一化后，观测到的总比率与以前世界范围和区域范围的研究相似。把观测到的世界范围的比率同根据加利福尼亚小的和中等余震图象的普通地震成丛发生模型进行了比较。把余震模型推广到大主震前的中等前震的情况。总的来说，观察到的世界范围的前震比率超过了推广的加利福尼亚普通模型的2倍。发现由地震的震源机制和区域构造所划分的地震子序列之间，前震比率有很大的有不同，逆断层地震的前震比率高于世界范围的平均值，而走滑断层地震的前震比率低于世界范围的平均值。在逆断层地震之中，大多数位于浅源消减带的地震有高的前震比率，而少数位于大陆的逆断层带地震有低的比率。这些差别或许能解释为什么以前的地质调查发现在加利福尼亚（特别是南加利福尼亚）发生的逆断层为典型的低比率，而世界范围观测的主要是浅源消减带的地震，它们是多前震的。假设这是真的，那么加利福尼亚普通模型或许大大地低估了卡斯凯迪亚地区潜在（M≥7）前震之后发生特大（M≥8）地震的条件概率。在哈佛大学目录里，在已识别的前震-主震对中，震级差与观测范围的均匀分布一致。     

断层泥伊利石物理化学特征及其意义

通过X射线衍射和化学分析等方法,研究了云南水电站断层泥中伊利石物理化学特征,结果显示：①伊利石物质的X射线衍射特征为⊿[（002）-（001）] ＞8,Ir＞1,BB1 ＜4°,属I＋ISII有序混层,膨胀层小于15％,晶胞参数b0=8.991A,1M多型结构;②K2O的平均含量9.1％变化范围在8.5％-10％之间;③K2O和Fe2O3含量之间为负相关,K2O含量与⊿[（002）-（001）] 2θ值呈正相关,而K2O与Ir值呈负相关.上述特征表明该断层泥伊利石是在低温（小于200℃）低压环境下生成.它的形成与断层稳定滑动机制有关.由此推测该断层未来发生大地震的可能性较小.     

云南地区中小地震静力学和动力学参数定标关系

通过消除S波观测谱中的传播路径、场地响应、仪器响应等影响因素,得到中小地震的震源谱.根据Brune震源模型,运用遗传算法计算了地震矩、应力降、震源半径等震源参数;通过考虑由于有限的仪器带宽带来的地震辐射能量低估及补偿问题,测定了中小地震辐射能量;分析了云南地区ML2.0 ～5.3地震静力学和动力学参数定标关系.结果表明:地震矩为2.1×1012～1.2 ×1016N·m,地震矩M0和震级ML的线性关系式为lgM0=1.01ML+10.59;震源破裂半径在86.9～1220.4m之间,地震矩M0与震源半径a之间的关系式为lgM0 =0.003a+ 12.90;应力降结果介于0.03 ～57.55MPa之间,当M0＜4×1014N.m时,应力降随地震矩的增大而增大,当M0≥4 ×1014N·m时,应力降与地震矩之间无明显的依赖关系;地震矩M0与拐角频率∫c明显有依赖关系,二者之间的关系式为lgfc=- lgM0+5.32;地震辐射能量ER在3.01×106～2.06×1012J之间,地震辐射能量ER与震级ML之间的关系为lgER=1.18ML+5.69.当M0＜4×1014N·m时,折合能量有随地震矩增大而增大的趋势,当M0≥4×1014N·m时,折合能量不随地震矩的增大而变化;地震视应力范围为0.02～31.4MPa之间,视应力与震源深度之间没有明显的依赖性.     

中法合作开展北天山山前暨昆仑山山前新构造与古地磁研究

由新疆工学院王功恪教授、游宏智副教授组织,新疆地震局参加的中国与法国合作研究北疆地区地质构造项目已开展工作。1988年10月18日至11月9日进行了第一次野外考察,参加考察的先后有16人。法国古地磁学家V.古的埃、J.高涅,地质学家P.塔波尼尔及其博士研究生J.菲力浦,古生物学家E.毕夫托等参加了乌鲁木齐至沙湾一带的工作。共采集晚侏罗纪、白垩纪及第三纪50多处400多个古地磁样品,用激光经纬仪实测了6条活断层陡     

利用IPA技术精细识别裂缝——以柴达木盆地南翼山工区为例

Sava D,Mavko G.基于岩石地球物理学的综合地质地球物理数据裂缝表征[J].前沿,2007,26:1140～1146.Sava D,Mavko G.Rock physics-based integration of geologic and geophysical data for fracture characterization[J].The Leading Edge,2007,26:1140～1146.

Burns D R,Willis M E,Toks(o)z M N,等.基于地震散射的裂缝属性分析[J].前沿,2007,26:1186～1196.Burns D R,Willis M E,Toks(o)z M N,et al.Fracture properties from seismic scattering[J].The Leading Edge,2007,26:1186～1196.

童亨茂,曹戴勇.柴达木盆地西部裂缝的成因机制和分布模式[J].石油与天然气地质,2004,25(6):640～643.Tong H M,Cao D Y.Genesis and distribution pattern of fractures in western Qaidam basin[J].Oil & Gas Geology,2004,25(6):640～643.

曹海防,夏斌,范立勇,等.柴达木盆地西部南翼山裂缝油气藏形成机制及分布规律[J].天然气地球科学,2007,18(1):71～73.Cao H F,Xia B,Fan L Y,et al.Formation mechanism and distribution rule of Nanyishan fractured reservoirs[J].Natural Gas Geoscience,2007,18(1):71～73.

H(o)cker C,Fehmers G.利用构造约束滤波进行快速构造解释[J].前沿,2002,21:238～243.H(o)cker C,Fehmers G.Fast structural interpretation with structure-oriented filtering[J].The Leading Edge,2002,21:238～243.

Hart B S.验证地震属性研究:超越统计[J].前沿,2002,21:1016～1021.Hart B S.Validating seismic attribute studies:beyond statistics[J].The Leading Edge,2002,21:1016～1021.

Yi L,Marhoon M,Dossary S A,等.边缘保持平滑及应用[J].前沿,2002,21:136～141.Yi L,Marhoon M,Dossary S A,et al.Edge-preserving smoothing and applications[J].The Leading Edge,2002,21:136～141.

Eberli G P,Masaferro J L,"Rick" Sarg J F 著.蔡希源,李思田,郑和荣,等译.碳酸盐岩储层和沉积体系的地震成像[M].AAPG论文集81.北京:地质出版社,2007,11:11～38.Cai X Y,Li S T,Zheng H R,et al.transformed.Edited by Gregor P Eberli,Jose Luis Masaferro,and J F "Rick" Sarg.Seismic imaging of carbonate reservoirs and systems[M].Beijing:Geology Press.AAPG Memoir 81,2007,11:11～38.

布朗.三维地震资料解释,第六版[M].AAPG论文集42,2004.Brown A R.Interpretation of three-dimensional seismic data,6th ed[M].American Association of Petroleum Geologists Memoir,2004,42.

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用P波走时残差研究深部结构

众所周知,人类赖以生存的地球,其内部结构远远不是通常所假定的球对称性质.从海拔八千多米高的喜马拉雅山到一万多米深的马里亚纳海沟之间的地形高差不过20公里,而大洋中部地区的M界面在海平面下只有10公里左右,帕米尔高原和西藏高原地区M界面却在海平面之下60公里左右.所以,M界面的起伏远比地形高差大得多.这种非对称性不仅表现在M界面起伏的差异,更重要的还表现出物质性质的差异.J—B走时表是全球范围内的平均走时表.地震台所在地区地壳和上地幔结构同J—B模型的差异,必然要反应到台站观测到的真实走时与J—B走时之间的差异上来.这个差异就是所谓的走时残差.     

海面电磁波散射的数值仿真

本文采用数值仿真的方法,在双尺度海浪模型下,在计算机上进行了电磁波与海浪相互作用过程的数值实验。计算了VV和HH极化波散射系数与入射角度、风速、风向等海况参数间的关系,并将计算结果与美国海军研究实验室（NRL）的四频率雷达测试数据做了比较,我们的结果比N.W.Guinard and J.C.Daley计算结果有明显改进。     

Estimation of lightning and sprite parameters based on observation of sprite-producing lightning power spectra

Spectrograms and ELF power spectra of magnetic variations originated from sprite-producing lightning discharges have been analyzed to extract both parent lightning and sprite parameters. Some of the spectrograms and power spectra have been found to have approximately quasi-oscillatory shape in the frequency range 0–40 Hz with maximum repetition period about 15–20 Hz. A theory predicts that this interesting peculiarity of the power spectra can be due to interference between electromagnetic fields originated from the parent lightning discharge and from the sprite. A smooth envelope of the power spectrum was shown to have a form of damped oscillations with period close to reciprocal value of sprite lag time. A technique of extracting sprite parameters based on the sprite-producing lightning power spectrum is proposed. The lack of the first Schumann resonance and other features occasionally observed in spectral resonance structure were also discussed.     

The spectra and temperature of cloud lightning discharge channel

Spectra of seven cloud lightning discharges are reported for the first time after captured with a Slit-less Spectrograph on Chinese Tibet Plateau. The structural characters are analyzed and compared with the spectra of cloud-to-ground lightning, and the results indicate that the spectra of cloud lightning show two different kinds of structure characteristics. One has the similar structure as those of cloud-toground lightning discharge, and the other is absolutely different. Meanwhile, more lines of OII with high excited energy are recorded in the spectra of cloud lightning discharge in comparison with that of cloud-to-ground lighting happening in the same region. Temperatures at different positions are calculated and temperature characteristics of these two sorts are analyzed, based to the wavelength, relative intensities and other transition parameters. We suggest that the physical process in the cloud discharge channels changes with much more rapid velocity and wider range compared to cloud-to-ground lightning. The differences between the two types of cloud discharge also reflect some discrepancies between the discharge characteristics. Supported by National Nature Science Foundation of China (Grant No. 40475007) and Foundation of Northwest Normal University (Grant No. NWNU-KJCXGC-03-21)     

高原地区云对地闪电首次回击的光谱研究

用无狭缝光栅摄谱仪,获得了青海西宁地区云对地闪电首次回击过程400～700nm波 长范围的光谱,并首次在闪电的单次回击光谱中记录到了波长为604.6nm和619.4nm的谱线. 将原子结构的理论应用于闪电光谱的研究,用多组态Dirac Fock方法,计算了有关光谱线 的 波长、振子强度以及相应的激发态能量等参数,理论与试验观测资料进行比较分析后发现, 高原地区闪电首次回击光谱的结构及跃迁特性与其他地区有明显的区别,除NII离子n=3 的低 激发态产生的跃迁谱线外,激发能量为13～14eV左右的中性NI和OI的跃迁增多,但很难观测 到OII离子的跃迁谱线.     

闪电放电过程的近红外光谱及温度沿放电通道的演化特征

利用无狭缝红外光谱仪, 获得山东地区闪电放电过程760~970 nm范围的近红外光谱.光谱特征分析得出: 近红外光谱主要是峰值电流之后、放电后期的辐射, 谱线主要是中性原子的贡献.首次讨论了放电后期的通道温度和光谱总强度沿放电通道的演化特征.结果表明, 通道温度较回击电流上升至峰值阶段降低, 约为16000 K; 不同闪电的光谱结构、通道温度差异不大, 反映了放电等离子体复合阶段的特性; 地闪通道的温度和光谱总强度沿放电通道略呈单调变化趋势, 接地点附近最大; 云闪通道的温度和光谱总强度沿放电通道非单调变化, 在通道的拐弯、分叉以及结点附近发生突变.     

Thunderstorm activity according to VLF observations at Kamchatka

The azimuthal distribution of lightning discharges and cyclone epicenters at a distance of up to 4000 km from the observation point at Kamchatka is given. The azimuths of lightning discharges were determined using an ELF finder, and the cyclone epicenters were determined from meteorological maps. Time dependences of the distribution of received radiations from lightning discharges have been obtained.     

用宽带干涉仪观测云内闪电通道双向传输的特征

利用闪电宽带干涉仪系统对闪电的观测表明，地闪和云闪的云内闪电通道都存在双向发展的特征. 闪电在云中负电荷区域初始激发以后，在通道两端发生向不同方向同时发展的击穿过程. 这两种击穿过程均产生较强的辐射，且辐射频谱特征十分相似，表明云内闪电通道两端发生的击穿过程可能均为负击穿过程. 相应电场变化表明闪电通道双向发展期间伴随着负电荷的向上转移. 这一观测事实与Kasemir早期提出的闪电通道双向发展的概念有一定的差异.     

Global Lightning Activity on the Basis of Inversions of Natural ELF Electromagnetic Data Observed at Multiple Stations around the World

The monitoring of global lightning activity and its spatial and temporal variations is known to be very essential for the study of global warming, the subject of greatest concern to human beings on planet Earth today. As a method of remote sensing for the global lightning distribution, we have proposed an inverse problem by using the data of natural electromagnetic noise in the ELF (extremely low frequency) Schumann resonance (SR) band observed simultaneously at a few stations around the world. The fundamentals of this inversion problem (or ELF tomography) to the SR data have been presented and the first attempt to deduce the global lightning distribution by means of the real SR data has been performed, which has indicated a possibility of snapshots of well-known thunderstorm centers on the globe. This ELF tomography consists of two stages. The first stage is the inversion of the ELF field power spectra to the distribution of lightning intensity by distance relative to an observation point. The obtained distance profiles of intensity of sources at a few stations are used as tomographic projections for reconstructing a spatial distribution of sources in the second stage. Maps of the global lightning distributions constructed by the result of inversions of ELF background field spectra obtained from three stations around the world show that the most active regions vary meridionally on the diurnal time scale being connected mainly with continental areas in the tropics. We do hope that this kind of inversion method to multi-stationed ELF data will be of great importance in the future.     

Verification of lightning strike incidence as a Poisson process

Recordings of lightning strikes to a wide range of practical structures are used to investigate the statistical nature of lightning strike incidence. Using the scatter of the lightning incidence onto a given attractive area, comparisons are made between the theoretically estimated and the observed strike incidence. It is shown that the strike frequency data are well described by a Poisson distribution for the ground flash density and a log-normal distribution for lightning current. The uncertainties in the estimation of ground flash density are determined, taking into account factors such as year-to-year variability and the observation time span.     

Reconstruction of the global lightning distribution from ELF electromagnetic background signals

The global lightning distribution has been obtained for the first time as the result of an inverse problem for the natural extremely low-frequency (ELF) electromagnetic background signals measured simultaneously at three stations: Lekhta (Karelia, Russia), Moshiri (Hokkaido, Japan), and West Greenwich (Rhode Island, USA). We employed a two-step technique consisting of: (1) inversion of ELF field spectra to a source distance distribution (distance profile) for each station of the network and (2) treating the obtained distance profiles as projections in the tomographic method. The structure of the source distance profiles reconstructed from experimental field spectra, varies during a day in a manner specific for each station, which can be explained generally by the temporal distribution of the sources in the tropical continental areas, so-called world thunderstorm centres (WTCs). The comparison of the obtained source distributions with the satellite data on lightning collected by Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) shows satisfactory agreement, which proves that our newly developed inversion technique is a suitable method for mapping global lightning.     

The Influence of the Acoustic-electric Coalescence on Phase and Mass Transfer of Supercooled Drops

The objective of this work is to study the influence of electrical discharge on the evolution of the cloud droplet spectra using a 1-D cloud model. It is shown that droplet motion and the electrical effects produced by lightning may cause a rapid and effective droplet coalescence process, with noticeably more phase transfer from liquid toward frozen water. As a measure of the drop spectra changes, we investigated variations of the radar reflectivity factor and the mass-weighted mean diameters at five temperature levels (0, −5, −10, −15, and −20C) with 15 combinations of the initial conditions. The model simulations suggest that about where the lightning occurred, after a few seconds, the initial unimodal spectra of supercooled water drops can be transferred to the bimodal spectra of unfrozen and frozen water drops. The number of newly created frozen drops is a few orders less than unfrozen water drops, but can still be very important for further transformations due to gravitational coagulation and other microphysical processes, e.g. glaciation. The results indicate that the procedure established to describe processes related to the electrical discharge and droplet spectra transformations can be used within a 3-D mesoscale model. It is concluded that the outcome can be also used to explain some of the physical characteristics inferred from polarimetric radar observations.