A quantitative characterization of the seasonal Lagrangian circulation of the Gulf of California from a three-dimensional numerical model

A set of four indices that quantify Lagrangian properties of the Gulf of California seasonal circulation were implemented from outputs of a three-dimensional numerical model. From trajectories of particles seeded over the entire Gulf, we calculated for 12 one-month periods the following indices: net and total distance traveled by the particles, the number of particles that are found within an area centered on the release positions after one month, and time taken by particles to escape from a 50-km-radius circle. These indices can be used for studies on transport of inert properties and passive planktonic organisms such as eggs and early-stage larvae; their use is illustrated for typical summer and winter conditions in the Gulf of California. These indices show the potential for connecting areas separated by a few hundreds of km along the eastern side of the Gulf, due to the strong seasonal up-gulf and down-gulf current. In the Northern Gulf, large displacements occur at the borders of the basin-wide seasonally reversing eddy that dominates the large-scale circulation (cyclonic in summer, anticyclonic in winter). On the other hand, the potential for self-recruitment areas is found as particles can be trapped for longer than one month within these eddies, as well as in smaller ones in the Northern Gulf, and near the coast of the peninsular side of the Southern Gulf, where current speeds are slow and many small capes and islands are present.     

用sPn计算四川省攀枝花地震的震源深度

本文推导了sPn与Pn波走时差与震源深度的方程,方程中sPn与Pn波的走时差与震中距无关,只与震源深度和区域地壳模型有关.根据该方程,提出用sPn与Pn的走时差来测定地震深度.2008年8月30日和8月31日在四川省攀枝花和会理交界处分别发生了Ms6.1、Ms5.6两次地震.但是,在四川省地震台网地震目录中缺少8月30...     

辽宁地区近震走时与震中距间关系研究

本文通过对辽宁数字地震台网控制区内近11年的地震观测数据进行处理分析,应用最小二乘法求回归方程等一系列相关公式进行计算,最终依据辽宁地区近震走时与震中距之间关系,归纳成表。为编制辽宁地区近震走时表提供可靠的数据依据。     

On far field occurrence of seismically induced landslides

Earthquakes may induce landslides at large distances from the epicentral area. In the last two decades, there have been many studies of this phenomenon to determine the causes that contribute to the occurrence of landslides at very long distances from earthquake epicenter. In this study, which is based on previously published works, a worldwide database comprising 270 earthquakes, including 150 during the instrumental period, was compiled to analyse the features of those landslides that occur at much further distances than maximum expected distances. From the analysis of the compiled data, it was observed that susceptible slopes can be grouped into five broad geological categories: jointed rock, marly–clayey (cohesive) soils, granular alluvial and/or colluvial sediments, volcanic soils, and residual soil slopes. These categories were equally likely to be associated with far field disrupted landslides, whereas far field coherent landslides were more frequent on cohesive soil slopes. Other factors, along with slope susceptibility may also contribute to far field landslides and increase the size of the area affected. Among these factors, site effects, antecedent rain and occurrence of seismic series have been cited. The analysis of available data also showed that for events of the same magnitude, far field disrupted landslides may occur at greater distances than coherent ones. The same database has also been employed to determine, for the first time, the upper bound curves for the maximum observed epicentral distances of several types of landslides and the maximum area observed to be affected by landslides, both based on the epicentral intensity of the events.     

珠穆朗玛峰国家自然保护区沼泽湿地提取及其退化风险评价

以珠穆朗玛峰国家自然保护区为研究区域,选取2009年23幅MODIS NDVI影像,采用傅里叶变换的HA-NTS算法去除云干扰,并重构NDVI时间序列图像.(1)根据研究区沼泽湿地与其他地物类型物候特征的差异,利用光谱角制图方法(SAM)获取了研究区2009年沼泽湿地的分布图.研究区沼泽湿地共有2 481.13km2,...     

基于资源和距离的旅游国际竞争潜力评价理论与实践

本文将旅游竞争力分为旅游竞争效力和潜力两个方面,并从旅游资源和距离两个方面构建旅游国际竞争潜力评价指标体系,运用综合评价法和从特定区域客源市场视角对中国旅游国际竞争潜力进行评价和分析.结果表明,与世界主要旅游强国相比,中国旅游国际竞争潜力综合评价值最高,竞争潜力很大,且在旅游资源方面拥有绝对优势,但在与客源地距离方面总...     

Natural Metrics in the Spaces of Elliptic Orbits

Different natural metrizations by Hölder type on the five dimensional space of Keplerian elliptic orbits are introduced. Certain applications of topological and metrical properties of the space of Keplerian elliptic orbits to several problems of Celestial Mechanics are discussed.     

用边长变化结果计算地应变及块体划分

在均匀应变的假设下，给出了由边长变化求解地应变的新方法，通过统计检验相邻三角形的最大主应变，可判别相邻测点是否位于同一个均匀应变体上，采用弹性位错理论设计的模拟算例表明，该方法能成功地将位于断层两侧的测量点分辨开。     

Towards a precision cosmology from starburst galaxies at z > 2

This work investigates the use of a well-known empirical correlation between the velocity dispersion, metallicity and luminosity in Hβ of nearby H  ii galaxies to measure the distances to H  ii -like starburst galaxies at high redshifts. This correlation is applied to a sample of 15 starburst galaxies with redshifts between   z = 2.17  and   z = 3.39  to constrain  Ω_m  , using data available from the literature. A best-fitting value of  Ω_m= 0.21^+0.30_−0.12  in a Λ-dominated universe and of  Ω_m= 0.11^+0.37_−0.19  in an open universe is obtained. A detailed analysis of systematic errors, their causes and their effects on the values derived for the distance moduli and  Ω_m  is carried out. A discussion of how future work will improve constraints on  Ω_m  by reducing the errors is also presented.