基于水稳定同位素的地下水型陆地植被识别:研究进展、面临挑战及未来研究展望          下载免费PDF全文

孙自永  王俊友  葛孟琰  乔树锋 《地质科技通报》2020,39(1):11-20

地下水型陆地植被具有重要的生态服务功能,但正遭受严重威胁,亟需在水资源管理中予以关注和保护.准确识别地下水型陆地植被是其管理和保护的前提.水稳定同位素方法是识别地下水型陆地植被的唯一直接方法,其中:①直接比较法只能获得植物对地下水利用的定性信息,但目前的应用最为广泛;②同位素混合模型能定量评估植物对地下水的依赖性,近期随贝叶斯模型的引入取得了较大进展.当前,植物对地下水利用的时空异质性增加了基于水稳定同位素的地下水型陆地植被的识别难度,还限制了小尺度上的研究成果向大尺度上的拓展;部分植物以间接方式利用地下水,对地下水型陆地植被的识别造成了困扰;根系吸水过程中的同位素分馏和同一植株内木质部水同位素组成的时空异质性常使植物样品的代表性受到质疑;采集到具有代表性的地下水和土壤样品也是当前面临的一个主要挑战.为应对上述挑战,未来应加强3个方面的研究:①研发植物木质部水同位素组成的原位在线连续观测技术,提升基于水稳定同位素的地下水型陆地植被识别的时空分辨率;②借助控制性的同位素标记实验,精细刻画地下水-土壤-植物体系内同位素体的迁移和分馏过程;③将同位素观测与具有物理学意义的生态水文模型相耦合,提高定量评估的分辨率和降低不确定性,探索解决时空异质性和升尺度难题的途径.  相似文献   

The interdecadal change of the leading mode of the winter precipitation over China     

Jingwen Ge  Xiaojing Jia  Hai Lin 《Climate Dynamics》2016,47(7-8):2397-2411

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诸氏鲻虾虎鱼卵黄蛋白原基因全长cDNA的克隆及表达     

余露军  蔡磊  李舸  陈小曲  陈琳  李建军 《海洋科学》2016,40(9):23-31

为了探讨诸氏鲻虾虎鱼(Mugilogobius chulae)卵黄蛋白原组织分布及17β-雌二醇(E2)暴露对雄性诸氏鲻虾虎鱼Vg的影响,作者采用RT-PCR、RACE方法克隆并分析了诸氏鲻虾虎鱼卵黄蛋白原(Vg)基因的全长cDNA序列,并对Vg在诸氏鲻虾虎鱼体内的组织表达分布及E2诱导后不同时间表达规律进行了研究。结果表明:获得的Vg cDNA序列全长5 067 bp,开放阅读框(ORF)含4 992 bp,编码1 663个氨基酸,含有信号肽、多丝氨酸区域,推测其编码氨基酸分子量为186.2 ku,等电点为9.31。荧光定量PCR结果显示,Vg在诸氏鲻虾虎鱼肝脏中表达量最高。E2诱导后,诸氏鲻虾虎鱼肝脏中Vg m RNA的表达量第1天达到小高峰,第3天达到高峰,第7天开始明显下降,第11天仍能维持较高水平。本研究成功克隆了诸氏鲻虾虎鱼Vg基因全长cDNA序列,诸氏鲻虾虎鱼肝脏是Vg主要合成场所,E2诱导雄性诸氏鲻虾虎鱼Vg的表达作为生物标志物用于近海环境雌激素类物质的检测具有良好的应用前景。  相似文献   

河北省海冰灾害风险评估和区划研究          下载免费PDF全文

袁本坤  郭可彩  商杰  黎舸  钟山 《海洋开发与管理》2016,33(1):117-120

开展海冰灾害风险评估和区划,有助于指导结冰海区沿岸各级政府制定和优化海冰防灾减灾决策,以最大限度地减轻海冰灾害造成的损失。本研究选取冰厚、密集度及冰期和各类承灾体密度、规模等作为评估指标,将河北省沿海县级行政区所辖海域作为基本评估单元,利用权重分析等方法,对河北省的海冰灾害风险进行综合评估。在此基础上,结合海冰防灾减灾的实际需求对河北省的海冰灾害风险进行空间区域的等级划分,并绘制风险等级分布图。所得结果较为真实地揭示了海冰灾害风险在河北省所辖海域的分布状况,可为河北省的海冰灾害风险管理等提供依据。  相似文献   

2015/2016年冬季胶州湾冰情特征分析          下载免费PDF全文

袁本坤  王玮  黎舸  焦艳  钟山  孙青 《海洋开发与管理》2016,33(11):77-79

因受陆地影响显著且盐度较低以及地理位置相对偏北,胶州湾每年冬季都有不同程度的结冰现象。文章利用卫星遥感和岸基监测所获取的冰情数据并结合历史资料,对2015/2016年冬季胶州湾的冰情进行综合分析,给出了该海域2015/2016年冬季的冰日、冰期、冰型、冰厚、海冰表面特征、浮冰密集度和结冰范围以及浮冰流向流速、地理分布等冰情基本特征。  相似文献   

Hydrogeochemical characterization and suitability assessment of groundwater in an agro-pastoral area,Ordos Basin,NW China     

Cheng Qian  Xiong Wu  Wen-Ping Mu  Rui-Zhi Fu  Ge Zhu  Zhuo-Ran Wang  Dan-dan Wang 《Environmental Earth Sciences》2016,75(20):1356

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A new algorithm for tight integration of real-time GPS and strong-motion records, demonstrated on simulated, experimental, and real seismic data     

Rui Tu  Maorong Ge  Rongjiang Wang  Thomas R. Walter 《Journal of Seismology》2014,18(1):151-161

The complementary advantages of GPS and seismic measurements are well recognized in seismotectonic monitoring studies. Therefore, integrated processing of the two data streams has been proposed recently in an attempt to obtain accurate and reliable information of surface displacements associated with earthquakes. A hitherto still critical issue in the integrated processing is real-time detection and precise estimation of the transient baseline error in the seismic records. Here, we report on a new approach by introducing the seismic acceleration corrected by baseline errors into the state equation system. The correction is performed and regularly updated in short epochs (with increments which may be as short as seconds), so that station position, velocity, and acceleration can be constrained very tightly and baseline error can be estimated as a random-walk process. With the adapted state equation system, our study highlights the use of a new approach developed for integrated processing of GPS and seismic data by means of sequential least-squares adjustment. The efficiency of our approach is demonstrated and validated using simulated, experimental, and real datasets. The latter were collected at collocated GPS and seismic stations around the 4 April 2010, E1 Mayor-Cucapah earthquake (Mw, 7.2). The results have shown that baseline errors of the strong-motion sensors are corrected precisely and high-precision seismic displacements are real-timely obtained by the new approach.  相似文献   

Precipitation and hydrological variations and related associations with large‐scale circulation in the Poyang Lake basin,China     

Qiang Zhang  Ying Liu  Guishan Yang  Zengxi Zhang 《水文研究》2011,25(5):740-751

Long streamflow series and precipitation data are analysed in this study with aim to investigate changing properties of precipitation and associated impacts on hydrological processes of the Poyang Lake basin. Underlying causes behind the precipitation variations are also explored based on the analysis of the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) reanalysis data. Besides, water intrusion from the Yangtze River to the Poyang Lake basin is studied. The results indicate that (1) seasonal transitions of precipitation are observed, showing increasing precipitation in winter, slight increase and even decrease of precipitation in summer; (2) analysis of water vapour circulation indicates decreasing/increasing water vapour flux in summer/winter; in winter, water vapour flux tends to be from the Pacific. Altered water vapour flux is the major cause behind the altered precipitation changes across the Poyang Lake basin and (3) occurrence of water intrusion from the Yangtze River to the Poyang Lake basin is heavily influenced by hydrological processes of the Poyang Lake basin. Effects of the hydrological processes from the middle Yangtze River on the occurrence of water intrusion events are not significant. The results of this study indicate that floods and droughts should share the same concerns from the scholars and policy makers. Besides, the altered hydrological circulation and associated seasonal transition of precipitation drive us to face new challenges in terms of conservations of wetlands and ecological environment under the changing climate. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

黄县弧形断裂探测、活动性鉴定及其地震地质意义   总被引：2，自引：2，他引：0  

王华林  王纪强  盖殿广  张昊  葛孚刚  刘霞 《震灾防御技术》2008,3(4):436-450

本文通过地质雷达探测、工程探测、地震地质调查、断裂断错和上覆第四纪地层年代测试等,确定了黄县弧形断裂的空间分布、运动性质、活动时代、垂直位移和滑动速率,鉴定了断裂的活动性,取得了一些有价值的成果。这些成果已在胶东北部沿海地区工程项目场地地震安全性评价工作、山东内陆部分潜在震源区划分与调整、山东省地震重点监视防御区判定研究中得到应用。本文的研究思路和方法对其它活动断层探测和断裂活动性鉴定有借鉴意义。  相似文献   

城市空间结构的复杂性研究进展   总被引：7，自引：3，他引：4  

房艳刚  刘鸽  刘继生 《地理科学》2005,25(6):754-761

城市空间结构一直是城市地理学和城市规划研究的核心之一,而复杂性是正在被逐步认识的现象。目前城市空间结构的复杂性研究是城市研究的前沿领域,对城市规划也具有重要的指导价值。本文首先论述了城市系统、城市空间结构与复杂性研究的关系,然后从城市子系统空间结构复杂性、城市系统空间结构复杂性和城市空间结构演化复杂性三方面综述了国内外的研究进展。最后讨论了目前城市空间结构的复杂性研究存在的问题,并就今后的研究重点做了展望。  相似文献