Sea surface heights obtained from Modular Ocean Model simulation and comparison with Topex/Poseidon data for the Indian Ocean

The Modular Ocean Model (MOM) is perhaps the most versatile ocean model available today for the simulation of the large scale circulation of the ocean. The Topex/Poseidon altimeter which has been operating since September 1992 has been providing sea surface heights (SSH) of the accuracy of 5–10 cms with a repeat cycle of 10 days. We examine in this paper, the SSH in the Indian Ocean obtained from a global simulation of MOM with a resolution of 1° in the longitude, 1/3° in the latitude between 30°S and 30°N and 20 levels in the vertical with climatological windforcing and restoring conditions on temperature and salinity. They are compared with the SSH from the Topex/Poseidon altimeter after suitable filtering in the time domain to remove smaller time and length scales. In addition, unfiltered data from both sources are analysed by estimating the cross-spectral density to find the coherence and crossphase at different frequencies. The agreement between the two, over most of the Northern Indian Ocean, especially the Arabian Sea and the Bay of Bengal is quite good.     

中国三叠纪中晚期—早更新世构造应力值的估算

选用具有测年数据的含石英或橄榄石的岩石，在透射电镜下观测位错密度，从而估算了中国三叠纪中、晚期—早更新世４３２个构造应力值（差应力值），初步发现在板块碰撞带或大断层带附近差应力值增大，而在板块内部则逐渐变小．在各构造期的晚期地壳上部平均差应力值也是不同的，印支期（２３０～２０８Ｍａ）为１０５．５ＭＰａ；燕山期（１７０～１３５Ｍａ）为９９．４ＭＰａ；四川期（１００～５２Ｍａ）为１０７．４ＭＰａ；华北期（３０～２３．３Ｍａ）为７６．７ＭＰａ；喜马拉雅期（１０～０．７３Ｍａ）为９２．６ＭＰａ．     

Multiscale segmentation of well logs

Examination of well logs leads to the observation that they exhibit characteristic behavior over a wide range of scales, differing from a foot to hundreds of feet. This behavior is not accounted for in conventional segmentation methods. The segmentation method that is proposed here aims to solve this problem. It is based on a multiscale representation of the well log. This is a representation of the well log at different levels of smoothness. The behavior of edges, which are associated with extrema of the first derivative, across scales is of great importance in the segmentation. Analysis of this behavior leads to a multiscale segmentation of the well log, in which a fine-scale segment is a part of one coarse scale segment only. In this way the geologist is able to analyze the log at different scales simultaneously. An extension of this approach is not to preserve all fine-scale information but to zoom in only on parts of the log where it is considered to be of interest.     

菲尔德斯半岛潮间带生态系统中的食物网

菲尔德斯半岛潮间带食物链是较简单的 ,一般说来在不利环境条件下的生物群落只有很少的消费者和较少的营养级。食物链中主要的生产者是大型底栖藻类 ,主要消费者是腹足类和石鳖 ,棘皮动物中的海胆与海星 ,甲壳动物 ,鱼和海鸟 ,海鸟和鱼占营养级的上层 ,草食软体动物位于中间营养级 ,大量的固着藻类 -叶状藻类、皮壳状藻类构成营养级的底层。观测实验表明 :(1 )海鸟和鱼类减少了草食性软体动物和肉食性螺类的数量 ;(2 )肉食性腹足类减少了草食性软体动物和固着无脊椎动物的数量 ;(3 )草食性软体动物减少了叶状藻类的数量并影响到皮壳状藻类的数量 ,在不清除消费者的实验中 ,皮壳状藻类显示出与其它固着生物竞争空间的优势。作者观察了并在本文中描述了异性底质与消费者对固着生物多样性的影响。壳状藻类在低潮带岩石表面占优势 ,其它的固着生物 (叶状藻类与固着无脊椎动物 )占据洞穴和狭缝。同质岩石表面固着生物的种类与数量低于异质性的岩石表面。清除岩石表面的消费者后叶状藻类与其它固着无脊椎动物的种数就超过皮壳状藻类     

用Lagrange函数平均法研究非均匀基流中的地形Rossby波

本文提出可以用平均限制性变分原理来研究非均匀基流中地形对Rossby波的影响。所得到的结果与用多重尺度法相一致,但却避免了多重尺度法中的冗繁运算,而且物理意义更加清楚,诸如波作用量密度、波能密度等物理量的定义也更自然、合理。     

STOCHASTIC THEORY OF THE DISTRIBUTION OF SEDIMENT PARTICLES SUSPENDED IN A TURBULENT FLOW

The random motion of sediment particles suspended in a turbulent flow is studied by means of stochastic process. Results of analysis of particle's frequency response to the random force exerted on the particle due to fluid turbulence suggest that only the lower part of the whole frequency range of the eddy motion will govern the motion of the particle. The mean values of particle velocity and displacement in the vertical direc- tion are calculated and it is found that particle velocity vp- can be decomposed into a mean motion and a velocity fluctuation vp- , where is equal to the fall velocity in tranquil fluid. An Ito^ random differential equation for particle dis- placement Yp is developed, from which a Fokker-Planck equation for the probability density function p(y,t) is derived on the basis of the theory of Markov process, where y denotes the vertical coordinate. The vertical distribution of the particle is thus interrelated to the random motion of the particle. The an effect that a particle will be subject to in the neighborhood or the bottom boundary is taken into consideration and a corresponding Fokker-Planck equation is developed. Analytical solution of the Fok- ker-Planck equation including the lift force effect shows that probability density p(y,t) for the particle displacement has a maximum value at y = H where the perpen- dicular component of the lift force balances the particle gravity. This theoretical result agrees with experimental observations as reported in literature.     

四川省地震重点监视防御区未来地震潜势的研究

本文通过历史地震及现今地震活动性的分析、活断层分段理论及地震空区理论的应用、地震平均复发间隔及复发条件概率的估算以及多学科专家综合评估方法的引入，对川西鲜水河－安宁河－则木河断裂和滇东小江断裂带（中－北段）上15个不同段落的地震潜势进行了深入的研究。进一步修正并重新圈绘出位于鲜水河－安宁河－则木河断裂带上的四川省地震重点监视防御区，其范围：北起道孚县的葛卡或者松林口一带，南至西昌市，沿鲜水河－安宁河－则木河主干断裂带展布，全长约350千米。按对未来地震震级估计的不同，该区可分成3段。第1段位于葛卡或松林口至康定之间，震级估计为7±1／4级；第2段位于康定与石棉之间，估计的震级是61／2±1／4；第3段位于石棉至西昌之间，震级估计为7－71／2。此外，研究结果还显示了小江断裂带上的新塘湾和寻甸一嵩明两个段落未来15年内强震发生的概率相对较高。     

The experimental study of parameters of rocks under ultrahigh-pressure state

The parameters of rocks in ultrahigh-presure state are very important to understanding the geodynamics and explosion engineering of rocks. In these experiments the plane wave dynamite lenses were used to drive the flying plates. The flying plate hits the target and produces the ultrahigh-pressure shock wave. The propagation velocity and the particle velocity of shock wave in rock samples were measured by probes, and the relation between density of rocks and pressure was obtained by Rankine-Hugoniot formulas. The maximum pressure in experiments was higher than 70 GPa. The ultrahigh-pressure state formulas obtained are: Limestoneρ=3.22+0.016p; Graniteρ=3.20+0.024p. In which the unit for ρ is g/cm³, the unit forp is GPa. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 96–103, 1991.     

多级判别在地震综合预报中的应用

本文阐述了多级判别在地震综合预报中应用的必要性,给出该数学方法的推导过程,并且以云南多震区——滇西南地震区为例进行实际判别计算,在所计算的工6个震例中其拟合预报准确率在80％以上;对1987年11月25日讯沧外.2级地震实际预报取得较好的效果。