确定外部扰动重力场的改进直接积分方法     

刘长弘  吴晓平  田家磊  赵东明 《测绘科学技术学报》2016,(6)

针对Stokes-Pizzetti积分用于外部扰动重力场计算中从空中趋近地面时存在着不连续和积分奇异的问题,对该式进行了改进。改进式引入地面计算点处的重力异常,得到一个从地面到空中统一适用的公式,并且中和了在地面计算点处的奇异性。类似地,改进了的Stokes公式在用于大地水准面计算时积分的奇异性同样起到了改善作用。  相似文献   

岩溶泉流量衰减曲线分析   总被引：5，自引：0，他引：5       下载免费PDF全文

常勇  吴吉春  刘玲  罗跃 《水文》2016,36(1):15-21

由于岩溶含水介质的强烈非均质性和各向异性,如何有效认识岩溶含水层内部的水文地质特征为研究难点之一,岩溶泉衰减曲线分析为认识岩溶含水层的一种有效手段。总结了目前广泛用于泉流量衰减曲线分析的几种常见方法,主要包括指数型衰减、非指数型衰减分析方法以及综合型的衰减曲线分析方法,讨论了管道可能对泉流量衰减曲线的影响,最后提出了今后对岩溶泉流量衰减曲线分析拟解决的一些关键问题。  相似文献   

松嫩平原哈尔滨地区地下水环境背景值分析          下载免费PDF全文

李天宇  董宏志  孔庆轩  卞建民 《水文》2016,36(3):24-28

受自然条件及人类活动的影响,地下水环境发生了较大的变化,地下水污染问题日益引起广泛的关注。正确确定背景值对地下水污染评价十分重要。以收集的松嫩平原哈尔滨地区150余组地下水水化学样品分析数据为依据,在分析区域流场、补给径流条件的基础上,选用数理统计法和经验法求取了研究区潜水和承压水地下水环境背景值,并对地下水环境背景值进行比较。结果表明:数理统计法以自然地理环境和人类长期活动的综合作用为基础,克服了经验法的不足,可较真实地反映研究区地下水背景状况;研究区内潜水中指标NO3-、Fe、Mn和承压水中指标Fe、Mn均为高背景值指标;区内地下水环境背景值与人类活动、地下水的补、径、排和沉积环境条件具有密切的关系。  相似文献   

渤海湾盆地车西洼陷陡坡带古近系沙河街组沙三下段“源-汇”系统          下载免费PDF全文

王星星  朱筱敏  宋爽  吴陈冰洁  贺敬聪  曹刚 《古地理学报》2016,18(1):65-79

依据渤海湾盆地车镇凹陷车西洼陷陡坡带古近系沙河街组沙三下段岩心、测井以及三维地震资料,对研究区的“源-汇”系统进行了研究。结果表明:(1)车西洼陷沙三下段为一个三级层序,并可进一步划分为低位、湖侵与高位3个体系域,其陡坡带沙三下段发育杂基支撑中砾岩、碎屑支撑中砾岩、杂基支撑细砾岩、碎屑支撑细砾岩、砂质砾岩、含砾砂岩、粗砂岩、中砂岩、细砂岩、递变层理砂岩、滑塌岩等11种重力流成因岩石类型及深湖泥岩,表现为典型的近岸水下扇沉积;不同体系域时期扇体规模整体呈“由大变小,再变大”的演化趋势。(2)车西洼陷陡坡带自西向东识别出6套供源体系,可分为有沟道为主供源体系和滑塌为主供源体系,分别形成沟道供源为主近岸水下扇和滑塌供源为主近岸水下扇类型,其中滑塌供源为主近岸水下扇中的滑塌变形构造更发育、更普遍,但其扇体规模较沟道供源为主近岸水下扇小。(3)进一步的“溯源”分析结果表明,沙三下段沉积时期,研究区物源区母岩以碳酸盐岩为主,其在强烈的构造活动、湿热气候作用下,易于发育石漠化古地貌,剥蚀作用较为强烈,由此形成的频发的季节性重力流进入湖盆,形成该地区的近岸水下扇沉积;不同体系域时期扇体规模的差异主要受物源区气候和植被覆盖的控制。  相似文献   

生态环境遥感分类数据矢量化方法与应用   总被引：4，自引：2，他引：2  

陈芸芝陈崇成  凌飞龙屈敏 《地球信息科学学报》2003,5(4):88-93

遥感分类数据矢量化建库是生态环境遥感制图及其应用分析过程中主要的处理内容和基础工作。以福建省海岸带生态环境遥感分类数据为例 ,在分析遥感图像处理系统对遥感分类和专题信息提取后处理中矢量化能力不足和结果存在严重缺陷的基础上 ,综合应用遥感和地理信息基础软件平台 ,提供的系列数据管理、分析和数据转换功能模块 ,开展基于生态环境遥感影像分类数据的矢量化建库技术探讨 ,提出一个生态环境遥感分类数据矢量化建库的通用技术方法和流程 ,并对矢量化结果做了一个简要的评价和分析 ,以满足大面积生态环境遥感调查、分析和制图的实际需要。  相似文献   

基于GDS室温条件下盐渍土强度特性的试验研究     

张洪萍  杨晓华  韩云山 《中国地质灾害与防治学报》2011,22(1):133-138

以新疆(北疆)地区S201公路沿线的盐渍土为研究对象,通过三轴剪切试验对盐渍土的强度特性进行了较系统的研究。试验结果表明,盐渍土与非盐渍土在力学性能上没有本质的区别,即应力-应变曲线大致都呈双曲线型,抗剪强度与破坏面上的法向应力成正比,且符合库伦定律;含水量和含盐量的变化导致试样发生的破坏形式不同。在含水量低和含盐量高时,试件具有脆性破坏的特征,在含水量高和含盐量低时逐渐显示出塑性特征;含水量和含盐量的变化对盐渍土的强度参数有重要影响,其中对粘聚力C的影响较大,表现较明显,而内摩擦角仅对含水量的变化表现敏感;极限强度与含水量和含盐量之间的关系符合二次抛物线变化规律,在不同应力作用下,抛物线形式不同。  相似文献   

带反馈优先的M/M/c排队在通信网络中的应用     

厉莉  朱翼隽 《成都信息工程学院学报》2006,21(6):897-902

在具有Bernoulli反馈的单队列单服务台排队模型的基础上，考虑通信网络中赋予反馈信元优先权的情况，将单个服务台推广到多个服务台，建立了具有反馈优先的M／M／c排队模型．在该排队模型中，信元的到达遵循泊松过程，服务时间服从指数分布，通过构造拟生灭过程和运用谱展开方法给出了平稳队长分布的算法，具体给出了C=2时平稳队长分布的显式表达式，以及在反馈优先和反馈非优先两种策略下的排队指标，并作出了相应的指标性能分析，得出信元在反馈优先策略下的平均逗留时间较短，进而说明了该排队模型在通信网络中有广泛的应用价值。  相似文献   

Lichenometry in the Cordillera Blanca, Peru: “Little Ice Age” moraine chronology   总被引：1，自引：1，他引：0  

Olga Solomina  Vincent Jomelli  Georg Kaser  Alcides Ames  Bernhard Berger  Bernard Pouyaud 《Global and Planetary Change》2007,59(1-4):225

This paper is a comparison and compilation of lichenometric and geomorphic studies performed by two independent teams in the Cordillera Blanca, Peru, in 1996 and 2002 on 66 ȁc;Little Ice Age” moraines of 14 glaciers. Using eleven new control points, we recalibrated the initial rapid growth phase of the previously established Rhizocarpon subgenus Rhizocarpon growth curve. This curve was then used to estimate the age of ȁc;Little Ice Age” moraines. The time of deposition of the most prominent and numerous terminal and lateral moraines on the Pacific-facing side of the Cordillera Blanca (between AD 1590 and AD 1720) corresponds to the coldest and wettest phase in the tropical Andes as revealed by ice-core data. Less prominent advances occurred between AD 1780 and 1880.  相似文献   

The Heat Island Effect Response to the Urban Landscape Pattern of Haikou based on the “Source-Sink” Theory     

LI Yujie  FU Hui 《资源与生态学报(英文版)》2022,13(2):257-269

The Landsat images of the 2000, 2005, 2010, 2015, 2018 are selected as the data source to retrieve land cover and surface temperature data. The contribution of Sink-Source landscape pattern to the heat island and its ecological effects on urban and rural gradient were analyzed by using Heat Index (HI), Sink and Source Landscape Contribution (CI_sink, CI_source) and Landscape Effect Index (LI) in Haikou. The results show that the heat island is concentrated on the West Coast, and in the central urban and Jiangdong New Area; the HI shows a pattern of decreasing value with the following land types: ȁc;Bare land>Artificial surface﹥Source landscape>Shrub grassland>Farmland>Sink landscape>Woodland>Water body”. In the central city section, the CI_sink and CI_source are relatively large in these five periods. The LI decreases rapidly along the urban-rural gradient, promoting the Urban Heat Island (UHI) to a large degree. In contrast, the suburban area contributes to a lesser degree. Overall, the LI fluctuates, the proportion of mitigating UHI is large, and there is a second peak outside the city center. The existing Source-Sink Landscape contributes the most to UHI in the central urban area, and this contribution decreases along the urban-rural gradient. With the continuous expansion of city-town areas, the proportion of Sink areas has increased along the gradient, and the proportion of Source areas has subsequently declined, resulting in the spatial transfer and diffusion of UHI. Therefore, a UHI mitigation strategy based on the theory of regional landscape systems is proposed here.  相似文献   

Research on Ecological Restoration Technology in Arid or Semi-arid Areas from the Perspective of the Belt and Road Initiative     

LI Yue  QI Shi  LI Jingjing 《资源与生态学报(英文版)》2022,13(6):964-976

In the new era of the rapid development of economic globalization and the community of human destiny, the implementation of the ȁc;One Belt and One Road” (OBOR) construction model is designed to coordinate environmental protection and economic development. Most of the countries along the Silk Road in the 21st century are developing countries, and the majority of them are facing the same ecological and developmental difficulties as China. In this paper, under the background of the ȁc;OBOR” strategy and on the basis of the distribution of global climate types, we selected Central Asia and Northwest China, which have temperate continental climates, as the research objects. We sorted out and summarized the main ecological problems faced by Western China and Central Asia during the development of the ȁc;Belt and Road” initiative. At the same time, in combination with the major ecological governance projects implemented in recent years, we proposed key ecological governance technologies that have a certain degree of scalability, such as key technologies for water resource utilization and protection, sand prevention and control, and saline-alkali land governance. The aim was to offer the experiences and a reference for providing technological models for the ȁc;one belt along the road” region and the country to build an effective ecological governance system. Two suggestions are then proposed for improving the feasibility and rationality of ecological governance technology in the construction of the ȁc;One Belt, One Road”. 1) With the implementation of the strategy of ȁc;OBOR” construction, the ecological threats the OBOR countries are facing cannot be ignored. Every country needs to jointly act to build an ȁc;OBOR” ecological civilization. 2) The participants must pay attention to the spatial heterogeneity and temporal dynamics of ecological carrying capacity, and provide data reference and support for the reasonable allocation of ecological governance technology.  相似文献