The utility of surfers’ wave knowledge for coastal management

In the face of environmental change, managing coastal resources effectively to benefit coastal stakeholders means understanding both complex coastal processes and the needs of stakeholders. Surfers are a culturally and economically significant group of coastal resource users who, in the act of participating in their sport, can acquire deep knowledge about the coastal environment and about wave resources in particular. As the primary users of wave resources, surfers could contribute substantially to both understanding the resources themselves and supplying locally-relevant data to inform their management. This study investigates the local knowledge of surfers through two surveys of more than one thousand California surfers and promulgates, based on survey data, a formal definition of surfers’ local knowledge as "wave knowledge." In so doing, this study makes the case that wave knowledge can be used to inform coastal management decision-making in those situations where wave resources, and thus the growing stakeholder group of surfers, could possibly be affected.     

预测地波定时信号传播时延的经验方法

在参考文献（２,３）的基础上,提出了含有大山区的复杂陆地地波路径的分段和确定各段路径等效电导率σｃ的方法,给出如何利用接收点场强实测值和已有的理论色散修正曲线（δｔ－ｄ）＾（６）近似计算色散修正值的方法,并对４条含大山区的复杂路径信号传播时延实测值ｔｇ＾－（收）与预测值ｔｇ进行比较,结果表明：路径分为３段等效时的预测准确度要比整段等效高得多。     

Standing Alfvén waves with m ≫ 1 in an axisymmetric magnetosphere excited by a non-stationary source

As a continuation of our earlier paper, we consider here the case of the excitation of standing Alfvén waves by a source of the type of sudden impulse. It is shown that, following excitation by such a source, a given magnetic shell will exhibit oscillations with a variable frequency which increases from the shells poloidal to toroidal frequency. Simultaneously, the oscillations will also switch over from poloidally (radially) to toroidally (azimuthally) polarized. With a reasonably large attenuation, only the start of this process, the stage of poloidal oscillations, will be observed in the ionosphere.     

Standing Alfvén waves with m ≫ 1 in an axisymmetric magnetosphere excited by a stochastic source

In the framework of an axisymmetric magnetospheric model, we have constructed a theory for broad-band standing Alfvén waves with large azimuthal wave number m 1 excited by a stochastic source. External currents in the ionosphere are taken as the oscillation source. The source with statistical properties of –white noise is considered at length. It is shown that such a source drives oscillations which also have the –white noise properties. The spectrum of such oscillations for each harmonic of standing Alfvén waves has two maxima: near the poloidal and toroidal eigenfre-quencies of the magnetic shell of the observation. In the case of a small attenuation in the ionosphere the maximum near the toroidal frequency is dominated, and the oscillations are nearly toroidally polarized. With a large attenuation, a maximum is dominant near the poloidal frequency, and the oscillations are nearly poloidally polarized.     

On the Dependence of the Equilibrium Range of Sea Wave Spectra with Wave Age

Donelan and Pierson have proposed a semiphysical model of the equilibrium sea wave spectrum, based upon a parameterization of wave growth and dissipation terms. Their model is applicable for fully developed seas only. In the framework of Donelan and Pierson's approach, this paper explores the dependence of the equilibrium spectrum upon wave age. To this end, we examine how the dissipation through wave breaking is expected to vary with wave age, according to the approach proposed by Longuet-Higgins in 1969. The constraint imposed by Longuet-Higgins' theory requires an increase of the equilibrium spectrum F(k,0) in the wind direction with increasing inverse wave age U/C_p. This is in accordance with Banner's empirically deduced statement that F(k,0) is proportional to (U/C_p)^0.5 in the equilibrium range. Our inferred F(k,0) tends to increase more or less linearly with U/C_p (we find F(k,0) proportional to 1 + 0.25(U/C_p - 0.83), rather than through a power law. If a power law is fitted we obtain F(k,0) approximately proportional to (U/C_p)^0.35 for the range 0.83 < U/C_p > 5. Finally, the roughness length of the air-sea interface is inferred from our modelled spectrum through integration of the form drag over wave number under rough conditions. This shows a wave age dependence that is compatible with measurements of wind stress performed in the field at various wave ages.     

储层条件下波速的变化规律及其影响因素的实验研究

为了在模拟储层的温度压力条件下,更精确地测定大庆砂岩样品在干燥、饱水和饱油等不同情况下的纵、横波速及其变化规律,首先对由于岩石的非完全弹性而引起的隐伏效应、滞后效应等因素对波速测量的影响进行了分析,提出了相应的改进方法以提高测试的精度．实验结果表明,波速随压力的增大以对数形式增加,随温度的升高呈线性减小．通过实测数据的分析和计算,提出了压力影响系数和温度影响系数,且认为它们与岩性参数有关．     

多层球体对电磁场散射响应的求解方法

为建立多层球体对电磁场散射响应的求解方法,将球外入射电磁场分为TM和TE极化波两部分,通过求解Debye位方程可得到多层球体各层中两种极化场的通解形式,利用边界条件建立了TM波（或TE波）球面波阻抗（或导纳）的递推关系,借助于阻抗（或寻纳）导出了球体对TM波（或TE波）所产生散射场的一般表达式．文中具体求解了球体对平面波径向和横向偶极子场的散射响应．     

厦门市的震前电磁波观测

本文记述了厦门市地震局几年来开展电磁波观测的情况,以及对各种非震异常信号的识别探索。     

Decompaction mechanism of deep crystalline rocks under stress relief

Within a geological massif in a stable geodynamical situation contacts on the grain boundaries in polycrystalline rocks at great depths are continuous and firm. The stress release of those rocks during drilling and excavation to the surface is accompanied by their disintegration (decompaction). The reason for the decompaction is generation of microcracks during stress release due to the difference between the elastic moduli of crystalline grains at their contacts. The mechanism of decompaction may occur not only in polymineral but in polycrystalline rocks as well. The method of decompaction evaluation of deep crystalline rocks under stress relief is presented. According to the calculations the initial manifestation of the decompaction effect in biotite gneisses will occur when they are extracted from the deep range of 0.8–1 km. The first microcracks arise on the grain borders between quartz–biotite and oligoclase–biotite. It is shown that the uplift of gneiss–granite varities of the rocks cut by the Kola superdeep borehole from depths exceeding 13–15 km will be possible in a form of separate mineral grains. Practical importance of the presented method is in an opportunity to evaluate the level of excavated decompaction. The method allow estimating the depth, from which the rock will be extracted only in a sludge form.     

On arrangement of source and receivers in SASW testing

This study investigates the effects of source and receivers arrangement on the Rayleigh wave dispersion curve in SASW testing. Analytical studies and numerical simulations with coupled finite and infinite elements are presented in this paper. It is shown that arrangement of source and receivers has a significant effect on test results, especially for soils with high Poisson's ratio or saturated soils. Larger source-to-receiver distance and receiver spacing usually give better results, and it is unnecessary to keep them equal. To satisfy the error control requirement in Rayleigh wave phase velocity measurement, source-to-receiver distance and receiver spacing should meet corresponding minimum values, which are proposed for different Poisson's ratios of soil in this paper.