地震波衰减的物理机制研究

对近年来有关地震波衰减的物理机制进行评述和初步研究认为,对于地壳介质,造成地震波衰减的主要原因是地壳内存在大量裂隙,裂纹中饱含水或部分含水,地震波传播时引起裂隙中的流体运动,从而造成地震波的衰减,对于上地幔,扩散控制的位错阻尼机制可能是造成地幔地震波衰减的一个重要原因,而上地幔软流层部分熔融的存在也是造成地震波衰减不可忽视的原因．     

Estimates of gravity wave drag on Mars: Indication of a possible lower thermospheric wind reversal

Spectral gravity wave parameterization suitable for planetary thermospheres applied to wind and temperature from Mars Climate Database reveals enormously strong drag incompatible with the wind distribution. It points out to a possible wind reversal in the 110-140 km layer similar to the one in the Earth’s lower thermosphere.     

Genetic type,distribution patterns and controlling factors of beach and bars in the second member of the Shahejie formation in the Dawangbei Sag,Bohai Bay,China

As an important reservoir type in the Bohai Bay Basin, China, lacustrine beach and bar sands which refer to the shallow water complex deposited mainly by nearshore, delta‐rim and buried hill‐related beaches as well as longshore bars were developed in a particular stage in the evolution of those faulted Cenozoic continental depressions. In the Chezhen Depression, for example, the Second Member of the Oligocene Shehejie Formation (abbr. as Es2 hereafter) formed during the rifting‐to‐thermal subsidence transitional stage. Although well developed in Es2, beach and bar sands are difficult to recognize owing to their relative thinness. The paper summarizes sedimentary characteristics of lacustrine beach and bar sands on cores and logs. Low‐angle cross‐stratification, swash stratification, as well as occasional small‐scale hummocky cross‐stratification resulted from storms can be observed in beach and bar sands. The paper distinguishes bars and beaches from each other in Es2 mainly based on the grain‐size, bed thickness, facies succession and log responses. In order to predict the distribution of beach and bars, a chrono‐stratigraphic correlation framework of Es2 in the study strata is established using a high‐resolution sequence stratigraphic approach. Es2 strata are sub‐divided into six medium‐scale cycles and the mapping of the high‐frequency cycles allows the geographic and stratigraphic distribution of both beach and bar sands to be predicted. The study shows that beach and bars are better developed in times of base‐level fall than in base‐level rise. Factors such as lake‐level fluctuation, sediment supply, palaeogeomorphology and palaeowind direction have exerted control on the formation and distribution of beach and bar sands. Finally, the genetic pattern of beach and bar sands in the Es2 unit has been constructed, which provides a foundation for the prediction of beach and bars reservoir in continental basins in general. Copyright © 2011 John Wiley & Sons, Ltd.     

基于模板技术的专题海图快速成图方法研究

首先分析了当前专题海图的生产现状,在此基础上,探讨了模板技术对专题海图快速成图的意义,介绍了基于模板技术的专题海图快速成图技术,并对专题海图制图模板结构进行了总体设计;最后从成图模式、工具平台和应用系统三个方面对基于模板的专题海图快速成图进行了方法上的实现。     

基于GRACE数据的格陵兰冰盖质量变化研究

基于GRACE得到的时变地球重力场数据反演了格陵兰冰盖2002～2011年期间的质量变化。结果表明:格陵兰冰盖2002～2011年的年消融总量为188±10km3/a,2002年以来冰盖整体的消融速率呈现出增加趋势;冰盖的消融区域主要集中在冰盖的东南部和西北部;自2008年以来,冰盖东南部的消融速率虽然有所放缓,但消融速率仍然维持在55±7km3/a;冰盖西北部的消融速率仍在增加,2008年以后达到了48±6km3/a。     

基于数据挖掘的渤海湾水生态环境特性研究

由于水生态环境数据的数量、覆盖范围和复杂性都在飞快地增长,如何科学、有效地利用这些数据,从中获取潜在有用的信息,成为水生态环境研究的重要问题.通过对多种海洋数据挖掘技术方法的综合分析,以渤海湾为研究背景,利用海洋环境卫星遥感数据,对渤海湾水生态环境特性进行了一系列的数据挖掘研究.利用k-means算法分别对2008和2009年渤海湾的生态环境遥感数据进行了聚类分析;利用Apriori关联规则算法对聚类离散化处理后的渤海湾生态环境遥感数据进行了关联分析.利用CART算法对2008和2009年渤海湾生态环境遥感数据进行了决策树分析.     

Incorporating uncertainty into the estimation of biological reference points for a spiny lobster (Panulirus penicillatus) fishery

The status of a fishery is often defined as the probability of fishing mortality rate exceeding a perilous level for long‐term sustainability. Lobster stock assessments are often subject to large uncertainty in input data and high levels of natural variability in lobster life history processes, which calls for incorporating uncertainty associated with both indicator and management reference points in an evaluation of biological risk of overfishing. Using a Monte Carlo simulation approach, we evaluated the impacts of uncertainty in modelling on the determination of the status of the Taitung spiny lobster (Panulirus penicillatus) fishery (Taiwan), which has not been quantitatively determined despite its commercial importance. The commonly used biological reference points derived from the per recruit model (F _0.1 the fishing mortality rate where the slope of the curve of yield‐per‐recruit model is 10% of the maximum slope and F _4Q%, the fishing mortality rate that reduces the expected egg production for a cohort of female lobsters to 40% of that produced in the absence of a fishery of the egg‐per‐recruit model) were influenced by uncertainties associated with lobster life history and fishery parameters. A large uncertainty in the current fishing mortality rate (F _cnr) and estimates of biological reference points (F _BRPs) increased the uncertainty in determining the risk of overexploitation throughout the confidence levels of the stochastic decision‐making framework. This simulation study suggests that the target reference point of F _40% is less sensitive to the input parameters’ uncertainty than F _0.1 We suggest a further evaluation of other F‐based references points and development of biomass‐based reference points before final selection and implementation for the management of the Taitung lobster fishery.     

基于SBAS技术的输电线路地表形变监测

地质灾害对输电杆塔和电网系统运行带来安全隐患,人工巡查无法及时发现地表缓慢形变导致的杆塔形变,且巡查效率低,成本高.为解决地质形变给输电线路带来的威胁,需监测输电线路沿线的地表形变.基于Senti-nel-1A卫星数据,以SBAS-InSAR为技术手段,对RT甲、乙线和YF直流线沿线实现周期性、低成本和高精度的形变监测...     

黑潮及相邻海域表层砂壳纤毛虫分布模式:以夏季黄海、东海至西太平洋断面为例

2019年夏季对沿黄、东海至西太平洋跨越黑潮一个断面(122°E～145°E)的表层砂壳纤毛虫群落进行调查,研究了黑潮中砂壳纤毛虫与相邻水体的差异.根据水文环境及各站位所处的空间位置,我们将研究区域划分为大洋边缘区域、黑潮区域和大洋区域.各站位砂壳纤毛虫的丰度范围为3.95～31.94 ind·L–1,种丰富度范围为6...