Influence of Adoptment of Geocentric 3D Coordinate System on Chinese Existent Maps     

CHENJunyong DANGYamin 《地球空间信息科学学报》2005,8(2):79-84

If a geocentric 3D coordinate system is adopted in China to replace 2D non-geocentric coordinate system, the coordinates of the surface points will be changed accordingly. The influences on the current maps of China, especially the topographic maps, are discussed due to the replacement of the coordinate systems. Taking the replacement of Xi‘an 80 coordinate system by GRS80 for a numerical example, this paper analyzes the changes of latitude, longitude, Gauss plane coordinates of the surface points, as well as the orientation and the length changes between the points on the map, including the changes of map border lines and sheet corner points.  相似文献   

Characterizing groundwater/surface-water interactions in the interior of Jianghan Plain,central China     

Du  Yao  Ma  Teng  Deng  Yamin  Shen  Shuai  Lu  Zongjie 《Hydrogeology Journal》2018,26(4):1047-1059

Hydrogeology Journal - Quantifying groundwater/surface-water interactions is essential for managing water resources and revealing contaminant fate. There has been little concern on the exchange...  相似文献   

长江中游沿岸地下水中有机质分子组成特征及其对碘富集的指示          下载免费PDF全文

薛江凯  邓娅敏  杜尧  罗义鹏  程一涵 《地球科学》2021,46(11):4140-4149

长期摄入高碘地下水（碘浓度＞100 μg/L）会造成人体甲状腺机能损伤.天然有机质被认为是影响高碘地下水形成的关键组分,为研究地下水中溶解性有机质（DOM）分子组成对碘富集的影响,选取长江中游沿岸浅层地下水作为研究对象,运用傅立叶变换离子回旋共振质谱仪（FT-ICR-MS）表征不同碘浓度地下水中DOM分子组成差异.研究发现碘易富集在还原环境的浅层地下水中,地下水中碘的浓度与溶解性有机碳（DOC）浓度无显著关系,DOM分子总数越多碘浓度越高;高碘地下水较低碘水DOM分子均一性、多样性更强,氧化程度和不饱和程度更高,含更多芳香性结构.长江中游沿岸高碘地下水的形成受DOM分子组成控制,主要与不饱和程度高尤其是含芳香性结构的大分子DOM有关,含芳香性结构的DOM分子与碘络合在高碘地下水的形成过程中起重要作用.   相似文献   

Study on inelastic displacement ratio spectra for near-fault pulse-type ground motions   总被引：3，自引：1，他引：2  

翟长海  李爽  谢礼立  孙亚民 《地震工程与工程振动(英文版)》2007,6(4):351-355

In displacement-based seismic design, inelastic displacement ratio spectra (IDRS) are particularly useful for estimating the maximum lateral inelastic displacement demand of a nonlinear SDOF system from the maximum elastic displacement demand of its counterpart linear elastic SDOF system. In this study, the characteristics of IDRS for near-fault pulse-type ground motions are investigated based on a great number of earthquake ground motions. The in? uence of site conditions, ratio of peak ground velocity (PGV) to peak ground acceleration (PGA), the PGV, and the maximum incremental velocity (MIV) on IDRS are also evaluated. The results indicate that the effect of near-fault ground motions on IDRS are signifi cant only at periods between 0.2 s - 1.5 s, where the amplifi cation can approach 20%. The PGV/PGA ratio has the most signifi cant in? uence on IDRS among the parameters considered. It is also found that site conditions only slightly affect the IDRS.  相似文献   

CORS网区域重力场变化与地面稳定性跟踪监测方法     

章传银  李爱勤  党亚民  毛卫华  蒋涛  王伟  杨强 《测绘科学》2019,44(6):29-36

为了实现地面稳定性降低时间与地点、持续作用时间与空间影响分布的全面跟踪监测,该文基于卫星定位连续运行站(CORS)站网观测数据,结合地表水、大气及海平面变化资料,提出了CORS站网时变重力场及负荷形变场精化的已知负荷移去恢复法,建立了基于时变重力场的确定性地面稳定性变化定量辨识准则。以丽水温州地区为例,利用2015-2017年CORS网及有关水文观测数据进行计算分析,根据40起已发生的历史地质灾害(险情)事件对结果进行验证:丽水温州地区的CORS网具备区域重力场变化与地面稳定性跟踪监测能力,具备地质灾害灾变过程追踪与前兆捕获能力,CORS站网的地质灾害前兆提前捕获率可达92.5%。  相似文献   

Instantaneous Shorelines as an Intermediate for Island Shoreline Mapping based on Aerial/Satellite Stereo Images     

Yamin Dang  Xinghua Zhou  Jun Xu  Shuqiang Xue 《Marine Geodesy》2018,41(3):219-229

Island shoreline mapping based on field measurements by collecting visually discernible features is costly and even unrealistic to be implemented in practice because of the nonuniqueness, fuzziness, and ambiguity of shoreline features. The MHHW (the mean higher high water) shoreline, i.e., the intersection of the coastal profile with the MHHW, is recommended to be chosen as a significant shoreline indicator of an island. An approach for mapping the MHHW shoreline using the aerial/satellite stereo images is proposed. In the proposed procedure, first, the height difference between the instantaneous shoreline and the MHHW shoreline is calculated by the ocean tide model; then the orthometric/normal height of the instantaneous shoreline is determined from the stereo images; last, the instantaneous shoreline is used as an intermediate for determination of the height of the MHHW shoreline. The proposed procedure is applied to the MiaoZiHu Island located in the East China Sea. Preliminary experimental result shows that in ideal cases, the horizontal positional accuracy of the extracted shoreline can reach 0.2 m from aerial images of 0.1 m resolution.  相似文献   

Galileo广播星历评估及其对定位精度的影响     

韩德强  党亚民  庞辉  薛树强  杨强  张龙平 《大地测量与地球动力学》2018,38(11):1165-1169

分析现阶段伽利略空间信号的精度,并评估伽利略广播星历及其对单点定位的影响。统计30 d健康卫星广播星历,结果表明,FOC和IOV两种类型的广播星历卫星轨道误差优于0.8 m,并且径向误差最小,法向误差次之,切向误差最大;伽利略卫星的钟差误差精度达到1.0 ns;从空间信号测距误差对伽利略卫星进行整体分析,广播星历精度优于1.0 m,FOC与IOV卫星精度相当;用广播星历进行事后单点定位的精度可以达到dm级。  相似文献   

From China’s Heavy Precipitation in 2020 to a “Glocal” Hydrometeorological Solution for Flood Risk Prediction     

Huan WU  Xiaomeng LI  Guy J.-P.SCHUMANN  Lorenzo ALFIERI  Yun CHEN  Hui XU  Zhifang WU  Hong LU  Yamin HU  Qiang ZHU  Zhijun HUANG  Weitian CHEN  Ying HU 《大气科学进展》2021,38(1):1-7

The prolonged mei-yu/baiu system with anomalous precipitation in the year 2020 has swollen many rivers and lakes,caused flash flooding,urban flooding and landslides,and consistently wreaked havoc across large swathes of China,particularly in the Yangtze River basin.Significant precipitation and flooding anomalies have already been seen in magnitude and extension so far this year,which have been exerting much higher pressure on emergency responses in flood control and mitigation than in other years,even though a rainy season with multiple ongoing serious flood events in different provinces is not that uncommon in China.Instead of delving into the causes of the uniqueness of this year’s extreme precipitation-flooding situation,which certainly warrants in-depth exploration,in this article we provide a short view toward a more general hydrometeorological solution to this annual nationwide problem.A“glocal”(global to local)hydrometeorological solution for floods(GHS-F)is considered to be critical for better preparedness,mitigation,and management of different types of significant precipitation-caused flooding,which happen extensively almost every year in many countries such as China,India and the United States.Such a GHS-F model is necessary from both scientific and operational perspectives,with the strength in providing spatially consistent flood definitions and spatially distributed flood risk classification considering the heterogeneity in vulnerability and resilience across the entire domain.Priorities in the development of such a GHS-F are suggested,emphasizing the user’s requirements and needs according to practical experiences with various flood response agencies.  相似文献   

南海东北部新构造运动及其动力学机制   总被引：1，自引：0，他引：1  

孙金龙  徐辉龙  李亚敏 《海洋地质与第四纪地质》2009,(3)

南海东北部地处欧亚板块与菲律宾海板块的交汇区,新构造运动活跃。根据地震活动性、震源机制解和GPS资料对该区的新构造活动特征进行分析,在此基础上讨论该区新构造运动的动力学机制。分析发现,菲律宾海板块NW向俯冲对该区的影响最为显著,导致了该区较强的地震活动性以及与俯冲方向一致的构造应力场。而印藏碰撞产生的侧向应力传递也影响到该区,控制华南地块向SE方向运动,并与菲律宾海板块的NW向俯冲共同作用,使华南地块在SE向运动的同时伴有逆时针旋转。印藏碰撞的SE向应力传递对俯冲产生的NW向水平挤压的抵消作用,使得地震活动性自东向西减弱以及构造应力场P轴方位角顺时针旋转。在这一背景下,区内滨海断裂带的活动控制了该区的地震、海岸带构造升降等新构造运动。  相似文献   

GPS���ܵ��㶨λ��Ӱ������ʱ������ؼ���ʩ����   总被引：1，自引：0，他引：1  

郑作亚  党亚民  卢秀山  郭金运  阳凡林 《大地测量与地球动力学》2009,29(5):107-111

??GPS??????λ?????????У?????????????????估???????λ??????????????????????????????????????????λ????????????λ?????????????????????????????????????????????????????????伸?ι?????????????????????????????Щ???????????????????????????????????????????????????????  相似文献