南海西南部海盆附近中尺度涡及其水文特征     

郑淑贤  鲍献文  丁扬  万凯 《海洋湖沼通报》2016,(4):1-10

根据"东方红2"于2011年9月在南海西南部11°N~15°N、111°E~114°E海域测得的CTD资料及据此的地转流计算结果,结合南海的海流数值计算结果的对比分析,得出南海西南部海盆附近水域中尺度涡的基本分布规律及其水文特征:(1)以12°N~13°N附近宽约100km的条带作为分界,其北部是气旋式运动,南部是反气旋式运动。(2)气旋涡中心产生上升流,底层水上升,中心密度大。表层表现为低温高盐高密特征;200m层表现为低温低盐高密特征;1 000m层则表现为低温高盐高密特征。(3)在反气旋涡中心产生下降流,海水密度小。表层表现为高温低盐低密特征;200m层表现为高温高盐低密特征;1 000m层则表现为高温低盐低密特征。(4)在8~9月,上述北气旋、南反气旋的分布流态基本不变;(5)季风的影响是因素之一,而地形影响更是调查区域双涡旋流动结构的重要动力机制。  相似文献   

基于层次分析法的德州地面沉降易发区的可拓学划分应用          下载免费PDF全文

张永伟  李红霞  商婷婷  贾超  梁浩  杨亚宾 《山东国土资源》2016,32(7)

基于物元模型的可拓学理论分析,提出华北平原德州地面沉降易发区的可拓学划分方法。利用地面沉降易发性分级、分类标准和影响因子分析,构造出经典域物元和节域物元,应用物元和可拓集合中的关联函数,建立了易发性等级综合评判的可拓评价模型,通过基于层次分析法的可拓学评价分析,采用正方形等间距(2km×2km)剖分了135个网格,再将剖分单元转化成面元,经过等值差分,得到了地面沉降易发区划结果。计算结果显示,可拓学方法能够实现定量化、多因子评价地面沉降易发性等级问题,从而科学合理地指导地面沉降综合分区防治。  相似文献   

Glacier changes in the eastern Nyainqêntanglha Range of Tibetan Plateau from 1975 to 2013     

JI Qin  YANG Tai-bao  HE Yi  CHEN Jie  WANG Kai 《山地科学学报》2016,13(4):682-692

Maritime-type glaciers in the eastern Nyainqêntanglha Range, located in the southeastern part of the Tibetan Plateau, are an important water source for downstream residents and ecological systems. To better understand the variability of glaciers in this region, we used the band ratio threshold(TM3/TM5 for the Landsat TM /ETM+ and TM4/TM6 for Landsat OLI) to extract glacier outlines in ~1999 and ~2013. After that, we also generated a series of glacier boundaries and monitored glacier variations in the past 40 years with the help of the Chinese Glacier Inventory data(1975) and Landsat TM, ETM+ and OLI data. The total glacier area decreased by 37.69 ± 2.84% from 1975 to 2013. The annual percentage area change(APAC) was ~1.32% a-1 and ~1.29% a-1 in the periods 1975-1999 and 1999-2013, respectively. According to the lag theory, the reaction time is probably about 10 years and we discuss the variations of temperature and precipitation between 1965 and 2011. Temperature and precipitation increased between 1965 and 2011 at a rate of 0.34°C /10 a and 15.4 mm/10 a, respectively. Extensive meteorological data show that the glacier shrinkage rate over the period may be mainly due to increasing air temperature, while the increasing precipitation partly made up for the mass loss of glacier ice resulting from increasing temperature may also lead to the low APAC between 1999 and 2013. The lag theory suggests that glacier shrinkage may accelerate in the next 10 years. Small glaciers were more sensitive to climate change, and there was a normal distribution between glacier area and elevation. Glaciers shrank in all aspects, and south aspects diminished faster than others.  相似文献   

津冀海岸线现状、变化特征及保护建议   总被引：1，自引：0，他引：1  

施佩歆  王福  商志文  康慧  肖国强  杨吉龙  李建芬  姜兴钰  陈永胜  田立柱  李勇 《地质通报》2016,35(10):1630-1637

根据覆盖全区的3期遥感影像和实地调查,以及对滨海新区和滦河口2个典型区更深入的案例研究(包括回溯至1870年、1950年的基准岸线及逐年遥感信息),对津冀沿海海岸线现状进行解译和分类,并分析岸线变化特征及成因。津冀沿海现状岸线总长度894km,可以划分为自然岸线、半开发岸线和人工岸线3类,长度分别为90km、329km和475km。1950年以前为自然因素主导的岸线变化,1950年以后变为人类活动主导的岸线向海推进,逐渐加强的人类活动至2010年达到顶峰。在全球海面上升和区域地面下沉的大背景下,海岸线的自然演化趋势应该是向陆蚀退,但是人类活动主导的岸线变化却表现为违反自然趋势的向海推进。今后,向海推进最前沿的围海造陆区将受到来自海洋越来越强烈的影响,亟需加强监测和防护。兼顾环境保护与开发两方面的长远需求,建议赋予海岸线新的定义与内涵,划定岸线保护红线,恢复部分岸线的自然属性。  相似文献   

莱州湾南岸全新世相对海平面变化重建     

田立柱  陶有兵  姜兴钰  陈永胜  施佩歆  商志文  李建芬  王福  王宏 《地质通报》2016,35(10):1679-1691

在对莱州湾南岸8个钻孔沉积物沉积结构及有孔虫特征分析基础上,识别相关海面标志层位,辅以加速器质谱AMS14C测年,重建了全新世相对海面变化历史,并讨论了海面变化的沉积响应及控制因素。约9200cal BP以前,海面快速上升,研究区海侵时海面于-21.5m左右;9200~8400cal BP海面上升速率减缓至约2mm/a;8400~8000cal BP海面由-14m快速上升至-5.5m,速率约为33mm/a;8000~7600cal BP,海面持续数百年停滞或微弱下降;7600~7000cal BP海面由-5.5m快速上升至0m以上,速率至少约为13mm/a;7000~6000cal BP海面缓慢上升至+2~+3m位置,速率约为3mm/a;约6000cal BP以后海面缓慢下降至现今水平。约9200cal BP以前、8400~8000cal BP、7600~7000cal BP时期的3次海面快速上升,是MWP-1C融水脉冲、诱发8.2ka冷事件的融水脉冲,以及MWP-2融水脉冲的中纬度地区响应。中全新世全球冰融趋于停滞后,由于研究区沉积盆地沉降速度较慢,在冰川均衡调整效应下,使+2~+3m的相对高海面得以呈现。  相似文献   

渤海湾西岸QX02孔Ⅱ海的识别及OSL年龄     

陈永胜  王福  姜兴钰  黎伟麒  李建芬  商志文 《地质通报》2016,35(10):1600-1606

以渤海湾沿海低地的QX02孔为研究对象,进行了沉积岩石学分析和底栖有孔虫统计,结合加速器质谱~(14)C测年和光释光(optically stimulated luminescence,OSL)测年,探讨了该孔记录的第Ⅱ海相层埋深和形成时代。第Ⅱ海相层厚度11.4m,记录相对海面高度-26.83~-15.43m。AMS~(14)C年龄表明,Ⅱ海形成于MIS 3早期、甚至更早。OSL年代学研究显示,Ⅱ海样品等效剂量离散度较高,并且主要集中在2个区间,计算得到新、老2个年龄阶段。基于OSL测年原理的常规判断,认为较老的83.5~62.6ka阶段系受曝光不充分组分的影响,通常采用较年轻的51.9~39.9ka阶段为QX02孔的Ⅱ海沉积年龄。但是,较老的一组年龄从新的视角,暗示了可能的原始沉积过程及相应的海侵发生时间,因而具有重要的年代学和沉积学意义。  相似文献   

渤海湾巨葛庄贝壳堤与下伏泥层有孔虫组合的海面变化意义     

李建芬  苏盛伟  商志文  姜兴钰  陈永胜  王福  田立柱  王宏 《地质通报》2016,35(10):1584-1589

根据巨葛庄贝壳堤及下伏泥层的有孔虫研究,讨论了贝壳堤底板和下伏泥层各类沉积环境的海面意义,以此作为海面标志点重建的古海面误差范围为±0.225~±0.625m。结合该贝壳堤底板和下伏泥层顶板的年龄数据,重建了3900~3300cal BP时的海面高度为-2.955~-2.715m。  相似文献   

Large-scale,seasonal flood risk analysis for agricultural crops in Germany     

Stefan Klaus  Heidi Kreibich  Bruno Merz  Bernd Kuhlmann  Kai Schröter 《Environmental Earth Sciences》2016,75(18):1289

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Characteristics of deuterium excess parameters for geothermal water in Beijing     

Kai Liu  Xiaojuan Qiao  Baoling Li  Ying Sun  Zhiping Li  Conglin Pu 《Environmental Earth Sciences》2016,75(23):1485

This study investigates the characteristics of geothermal water in 10 geothermal fields in Beijing. The relationships between the deuterium excess parameter (d) and temperature, depth, age of geothermal groundwater, groundwater flow field, and Eh were investigated using geothermal groundwater samples. Results showed that (1) the average d value of geothermal water is 5.4, whereas that of the groundwater in normal temperature is 6.04. The differences are induced by the oxygen isotope exchange during the water–rock interaction, which may be more easily completed in geothermal water than in cold groundwater. (2) The d value increases remarkably with the age of the geothermal groundwater. The d value increases from 11.2 to 14.6 when the age of the geothermal water is 12,760 ± 130 a and 38,960 ± 630 a, respectively. Moreover, the isotope heat exchange for composition of the hydrogen and oxygen isotopes in the geothermal groundwater proceeds sufficiently with time. (3) The d value decreases from 5.72 to 3.03 when the depth increases from 125.13 to 3221 m. Generally, in the same area, the d value decreases with depth because the temperature is increasing. (4) The d value of the groundwater gradually reduces from the northern recharge area to the southern discharge area. The average d value is 7.31 in the northern recharge area and 5.68 in the middle Beijing Depression, whereas the d value in the southern area of Fengheying is ?9.20. The larger difference in d values between the recharge and discharge areas is due to the slower velocity of underwater flow, which induces longer time for oxygen exchange. (5) The relationship between the d and Eh is complex. When Eh is <200 mV, the d value of the geothermal water decreases with the decrease in Eh. When Eh is higher than 200 mV, the d value increases slightly with the decrease in Eh. The study of the characteristics of deuterium excess parameters for geothermal water could provide a scientific isotopic evidence for assessment and exploitation measures in geothermal groundwater systems.  相似文献   

Study on Longitudinal Deformation Profile of Rock Mass in a Subsea Tunnel     

Shu-Guang Song  Shu-Cai Li  Li-Ping Li  Qian-Qing Zhang  Kai Wang  Yi Zhou 《Marine Georesources & Geotechnology》2016,34(4):376-383

During tunnel excavation, the deformation of surrounding rock due to the unloading of rock mass will vary with time. However, the measured displacement of surrounding rock is only a part of the actual longitudinal deformation profile. There is a need to analyze the longitudinal deformation profile to identify the deformation state and evaluate the stability of surrounding rock mass. In the present article, the variation of pre-deformation of surrounding rock due to excavation was analyzed, and the release coefficient was obtained from the measured results. For the Qingdao subsea tunnel, the measured crown settlement of surrounding rock was analyzed using the regression analysis method, and the longitudinal deformation profile of rock mass was simulated using the numerical calculation method. Moreover, based on the conditions of the subsea tunnel, a solid-fluid coupling model test was carried out to check the reliability of the numerical calculation results. The results of the model test were consistent with the numerical calculation results.  相似文献