黄海海浪季节变化的数值模拟研究   总被引：3，自引：2，他引：1  

陈国光  翟方国  李培良  刘晓 《海洋科学》2016,40(11):155-168

利用第三代海浪数值模式SWAN,研究了黄海海浪有效波高的季节变化特征及相关的物理过程。结果表明,在黄海的大部分区域,混合浪有效波高的最大值出现在冬季,而最小值则基本出现在夏季。北黄海北部和山东半岛南岸的近海海域呈现稍微不同的季节变化,有效波高的最大值出现在春季。全年4个季节中混合浪有效波高的空间分布基本一致:均在济州岛西南最大,沿黄海中部区域向北和由中部区域向近岸区域逐渐减小。黄海海浪为风浪占主,涌浪有效波高远小于风浪有效波高。在黄海的大部分区域,白冠耗散和四波非线性相互作用对黄海海浪的季节变化均至关重要;对于外海区域,四波非线性相互作用更为重要,而对于近海区域,白冠耗散则影响更大。本研究旨在研究黄海海浪的季节变化特征及其物理过程,为进一步探讨该海域海浪在其他时间尺度上的变异特征和动力学过程提供研究基础。  相似文献   

反渗透海水淡化技术现状和展望     

高从堦  周勇  刘立芬 《海洋技术学报》2016,(1):1-14

反渗透膜技术于20世纪60年代取得突破性进展,促使反渗透海水淡化在近50年间高速发展,淡化产能自20世纪90年代起激增.海水反渗透(SWRO)淡化已成为目前投资最省、成本最低的利用海水制备饮用水的过程.文中主要对海水反渗透淡化的发展状况进行了介绍,如膜和组件的改进,关键设备高压泵和能量回收装置效率的提高,多种工艺过程的不断发展,包括预处理和后处理的新工艺,以及对环境的影响和相应对策等.反渗透技术的发展也推动了其他膜分离技术的进步,并扩展其应用领域.预计在不久的将来,膜技术在海水淡化和水再利用、扩大和保护水资源、循环经济、清洁生产、改造传统产业、节能减排及提高人民生活水平等方面发挥的作用会越来越显著.  相似文献   

Calculation method for thickness of discontinuous boundary layer of engineering pavement     

ZhongQiong Zhang  QingBai Wu  Peng Zhang  SiRu Gao 《寒旱区科学》2016,8(6):461-466

The boundary layer is a buffer layer of water and heat exchange between the atmosphere and permafrost.Based on the atmospheric boundary layer and heat transfer theory,we established a method for determining the boundary layer thickness of engineering pavement(asphalt and sand pavement)in permafrost region.The boundary layer can be divided into the Boundary Layer Above Surface(BLAS)and the Boundary Layer Below Surface(BLBS).From in-situ monitoring data,the thickness of BLAS was determined through the laminar thickness,and the thickness of BLBS was determined through ground temperature,the heat conduction function,and the mean attenuation function(α).For asphalt pavement,the BLAS thickness varied between 2.90 and 4.31 mm and that of BLBS varied between 28.00 and 45.38 cm.For sand pavement,the BLAS thickness varied between 2.55 and 3.29 mm and that of BLBS varied between 15.00 and 46.44 cm.The thickness varied with freezing and thawing processes.The boundary layer calculation method described in this paper can provide a relatively stable boundary for temperature field analysis.  相似文献   

考虑地球曲率影响的重力中间层校正计算及其精度分析     

张伟  廖国忠  孙涛  张秋冬 《大地测量与地球动力学》2016,36(5):391

介绍一种考虑地球曲率影响的“球冠模型” 重力中间层校正算法,并通过不同算例对比该算法与以往“圆柱体模型”算法之间的差值。结果表明,其差值的数量级最大可达0.4 mGal。  相似文献   

长岛县南五岛土壤地球化学特征及环境质量评价          下载免费PDF全文

衣伟虹  王松涛  王江波  郭志谦  厉耘 《山东国土资源》2016,32(12)

以长岛县南五岛土壤为研究对象,对区内土壤元素的含量特征进行分析,并对土壤环境质量进行评价。结果表明：研究区土壤平均含量与烟台市、山东省以及全国土壤平均水平相比,除CaO,Na2O,Hg,S,Se,P,F元素含量差异较明显,其他大部分元素含量相对稳定,元素含量的高低不仅与研究区背景条件有关,也与人类活动密切相关。研究区土壤环境质量整体较好,大部分区域属于清洁区和尚清洁区,仅城区局部受到一定程度的Cd,Hg,Zn污染。  相似文献   

Where Are the Women? Accounting for Discrepancies in Female Doctorates in U.S. Geography     

David H. Kaplan  Jennifer E. Mapes 《The Professional geographer》2016,68(3):427-435

Although there have been noticeable improvements in recent years, geography continues to be a predominantly male discipline. The percentage of women receiving PhDs in geography has tracked lower than the U.S. average of female PhDs. Previous studies of women's contribution to geography have focused on personal accounts or on the study of some of the most prominent practitioners, with a few studies using basic data on PhDs awarded and Association of American Geographers membership to determine trends. This article provides a comprehensive overview of doctoral degrees in geography by gender, over time, and across all universities in the United States by examining an alternative database, that of doctoral dissertations. The analysis yields three separate types of results. First, historical and contemporary variations among U.S. universities are examined. Second, data indicate that male and female doctoral students differ in the sex of their advisor. Third, a simple regression model explains some of the discrepancies in the proportion of female doctoral students by department. In sum, this article provides a comprehensive empirical study of the factors that might contribute to the continued disparities in female doctoral students in geography.  相似文献   

Effects of initial step height on the headcut erosion of bank gullies: a case study using a 3D photo-reconstruction method in the dry-hot valley region of southwest China   总被引：1，自引：0，他引：1  

Baojun Zhang  Zhengan Su  Dan Yang  Yifan Dong  Liang Xiao 《自然地理学》2016,37(6):409-429

Abstract

Headcut erosion has been recognized as one of the main processes involved in gully development in the dry-hot valley region of southwest China. To examine the effect of initial step height on headcut erosion processes, three headcuts were constructed ranging in height from 0.75 to 1.25 m on an active bank gully head, and a series of scouring experiments were conducted under a flow discharge of 120 L min^?1. The morphological evolutions of the plunge pools and soil loss volume were estimated by three-dimensional photo-reconstruction methods (3D-PR). As the step height increased, the experimental results showed that: (1) the transformed potential energy and shear stress would increase by approximately 4.89 J s^?1 and 26.4 Pa on average when the step height increased 0.25 m; (2) the mean depth and width of the plunge pool exhibited obvious growth, and the morphology of the cross-section developed from approximately V-shaped to U-shaped; and (3) soil loss volume increased logarithmically, with total soil loss volumes of 0.076, 0.105 and 0.116 m³, respectively. Although the significant effects of the initial step height on headcut erosion were verified, further quantitative studies are required to quantify the mechanism of headcut erosion, especially for plunge pool erosion.  相似文献   

TRACE ELEMENT DISTRIBUTION AND IMPLICATIONS IN SEDIMENTS ACROSS THE ALLERØD–YOUNGER DRYAS BOUNDARY IN THE NETHERLANDS AND BELGIUM          下载免费PDF全文

ALEXANDRE V. ANDRONIKOV  ANNELIES VAN HOESEL  IRINA E. ANDRONIKOVA  WIM Z. HOEK 《Geografiska Annaler: Series A, Physical Geography》2016,98(4):325-345

In the Northern Hemisphere, the Younger Dryas cooling occurred between 12.8 and 11.7 ka bp . This cooling is thought to have been the result of an abrupt change in atmospheric and oceanic circulations. One of the hypotheses explaining such a change suggests that just before the onset of the Younger Dryas cooling, multiple airbursts/impacts occurred over the Northern Hemisphere. We studied the late Pleistocene sediments from the Netherlands and Belgium to check whether a sudden short event might have taken place just before the onset of the Younger Dryas cooling. The geochemical features revealed suggest that such events might have occurred. The presence of products of biomass burning is suggested on the basis of trace element features of sediments from the lower Younger Dryas boundary. The presence of a volcanic component and a component resulting from extensive biomass burning in the sediments of c. 12.9 ka bp are indicated on the basis of trace element features. The volcanic component may be related to the Laacher See volcano eruption, whereas the cause of the extensive biomass burning remains unclear.  相似文献   

黄铁矿ReOs法测年在胶东金矿中的应用初探          下载免费PDF全文

李洪奎  耿科  禚传源  梁太涛  张玉波 《山东国土资源》2016,32(4):1-6

该次工作为黄铁矿Re-Os法测年在胶东金矿中的首次应用。在大尹格庄金矿中获得了由3件黄铁矿样品组成的(144.8±1.8)Ma等时线年龄,暗示着大尹格庄金矿区可能存在一期晚侏罗世的Au成矿事件。通过对大尹格庄、夏甸、土堆金矿黄铁矿Re-Os同位素年代学的研究,表明黄铁矿的Re-Os同位素特征在胶东金矿中具有一定的复杂性。该文总结了影响黄铁矿Re-Os同位素测年结果的因素,认为在利用该方法进行金矿床定年时,应当将不同期次黄铁矿分别送样,适当拉大采样间距,并尽可能降低实验测试误差,以期获得更精确可靠的年龄。  相似文献   

New tectonic map of Northern-Central-Eastern Asia:Position and evolution of Mesozoic sedimentary basins     

《世界地质(英文版)》2016,(4):261-276

The beginning of the XXI century was marked a new rising of the international tectonic cartography as a result of analysis and synthesis of a huge volume of geological information obtained for the territory of Asia especially during the last 30 years. The previous tectonic maps for Asia were created in the 1960 s--1970 s of the last century. Since that time,the national geological surveys have compiled tectonic maps exclusively in the limits of their own state boundaries. The international cooperation of five countries since 2002( Russia,China,Mongolia,Kazakhstan and Republic of Korea) gave a unique possibility to join the data into a united cartographic form as Atlas of Geological Maps( since 2002-Atlas of Geological Maps of Central Asia and since 2007-Atlas of Geological Maps of Northern-Central-Eastern Asia). Both atlases include four maps: geological,tectonic,metallogenic,and energy resources. Tectonic Map of Northern-Central-Eastern Asia and Adjacent Areas at scale 1 ∶ 2 500 000 was the key map for further compilation of the metallogenic and energy resources( coal,oil and gas) maps. By this reason,special attention was given to showing the structure and composition of the Mesozoic sedimentary basins in Northern-Central- Eastern Asia as the most perspective structures for oil-and-gas and coal prospect.  相似文献