北京市GPS网解算时IGS站的选取实验

用实验的方法,讨论了北京市GPS台网在用GAMIT软件解算时,选取IGS基准站的空间分布(南北半球、网内网缘、均匀展布)、数量分布(0到8个IGS站)对解算结果精度的影响。由于受观测站数量和IGS站观测数据质量的影响,在保证精度的前提下,为了提高观测数据的利用率,需要增加IGS站数量。根据2004全年的解算结果,北京台网选择9到10个IGS站较为合适。     

川滇GPS地壳形变监测网的观测与数据处理

介绍中美合作建立的川滇ＧＰＳ地壳形变监测网的布设和观测情况。利用ＧＡＭＩＴ和ＧＬＯＢＫ软件分别对已完成的两期观测数据进行了处理，基线相对精度优于０．１ｐｐｍ。对两期观测的部分基线结果作了比较，得出了一些有益的结论     

中国GPS地壳运动监测网的精度分析与评定(1992～1996)

中国ＧＰＳ地壳运动监测网于１９９２～１９９６年进行了多期观测,观测资料全部采用ＳＮＡＰＳ软件和精密星历进行解算,对解算结果的统计分析与精度评定表明：全国网的基线长相对精度为１０－９,区域网的基线长相对精度为１０－８。     

GPS监测地壳运动数据处理

介绍GAMIT软件的参数设置，以消除或减弱GPS的主要误差，获取高质量的基线处理结果。通过对GAMIT的基线解算结果H文件的处理，求解基线的重复率，平面上重复率不超过3mm，垂直方向不超过7mm，并对基线解算质量进行了评定。在研究全球板块运动或区域性地壳形变时，以GPS单天解的基线结果作为输入量，考虑各期计算结果之间的朴素联系，计算得到台站漂移量和漂移速度，从而得到地壳运动信息，对中国境内IGS站的算例分析表明，在ITRF2000框架下，计算出的漂移速度与IGS站提供的速度大小与方向基本一致。     

2000国家GPS大地控制网数据处理方法与结果

介绍了我国GPS大地控制网的基本情况,阐述了结合地壳运动观测网络工程建立全国统一的“2000国家GPS大地控制网”的意义,并介绍了整网平差中采用的技术方法和最后平差结果及精度。     

GPS在胶南市地理信息工程中的应用

在胶南市应用GPS建立三等平面控制网及高程拟合作业过程中，所采用的数据处理方法提高了平面精度和高程拟合精度。该GIS工程证实，应对平面网的起算点进行精度检测和保留三维无约束平差中精度较低的短基线。就高程拟合而言，应采用多种方案对已知GPS水准点进行各种精度检验，同时对所求点的拟合高程进行精度检验，以多种拟合方案所计算出的所求点拟合高程的均值作为最或然高程，计算每种拟合方案的所求点拟合高程中误差及拟合高程与最或然高程的最小差值和最大差值；然后，综合考虑所有精度检验结果，并从中找出一种最优拟合方案。     

GPS监测青藏板块运动数据的GAMIT/GLOBK处理方法及有关问题

结合喜马拉雅山板块运动 Ｇ Ｐ Ｓ 监测资料,较系统的讨论了 Ｇ Ａ Ｍ Ｉ Ｔ／ Ｇ Ｌ Ｏ Ｂ Ｋ 进行精密 Ｇ Ｐ Ｓ数据处理的理论和方法,着重对 Ｇ Ａ Ｍ Ｉ Ｔ 处理各时段解与 Ｇ Ｌ Ｏ Ｂ Ｋ 综合处理单时段解及其处理过程中应注意的有关问题做了较详细的讨论,对高精度 Ｇ Ｐ Ｓ 数据处理和分析具有重要参考价值。     

对城市GPS控制网的优化设计

优化设计城市的GPS控制网,是有效发展城市控制网建设的重要条件.本文结合GPS控制网的特点,浅谈如何对GPS控制网进行优化设计,提高其性能.     

GPS和电子水准仪在烟台控制网中的应用

采用全球卫星定位系统GPS施测了三等控制网，作为首级平面控制网。为提高观测速度、精度和可靠性，采用DL-102C电子水准仪建立了三等水准网作为首级高程控制网，用三等水准联测过的GPS控制点作为起算点进行GPS高程拟合。三等GPS网的总点数为57个，联测国家二等三角点4个，利用旧点9个，新布设GPS控制点44个，平均边长2．46km，控制面积约350km^2，在1980西安坐标系下进行平差，同时在烟台城市坐标系下平差计算，使开发区与城市建成区的控制网能够紧密地联系起来。三等水准网的总点数为41个，起算点为2个国家一等水准点，往返测水准路线总长为203．4km。平面精度和高程拟合精度均达到了国家规定的指标要求。     

Zooplankton spatial and diurnal variations in the Changjiang River estuary before operation of the Three Gorges Dam

Estuarine plankton communities can serve as indicators of ecosystem modification in response to anthropogenic influences. The main objectives of this study were to describe the spatial distribution and diurnal variability in zooplankton abundance and biomass over almost entire salinity gradient of the Changjiang (Yangtze) River estuary and to provide a background reference for future studies. To accomplish this, data were collected from 29 stations in the estuary from May 19 to 26, 2003, including two anchor stations. The spatial and diurnal variations in zooplankton characteristics, i.e. abundance, biomass, and gross taxonomic composition, were examined. Generally, both the abundance and biomass gradually increased seaward and presented distinct spatial variations. In addition, the spatial data revealed a significant correlation between abundance and biomass; however, there was no significant correlation between abundance and biomass for the diurnal data. Although the zooplankton composition indicated distinct spatial differences in terms of dominant groups, copepods accounted for >50% of the total zooplankton abundance in most regions and times. Three zooplankton assemblages were recognized through hierarchical cluster analysis. These assemblages existed along the salinity gradient from fresh water to seawater, and their positions coincided with those of the three principal water masses in the estuary. The assemblages were classified as: (1) true estuarine, (2) estuarine and marine, and (3) euryhaline marine, which were characterized by the copepods Sinocalanus dorrii, Labidocera euchaeta, and Calanus sinicus, respectively. Both spatial and diurnal data indicated that there was no significant correlation between zooplankton abundance/biomass and depth-integrated phytoplankton abundance.     

长江上游表壳岩系Pb同位素组成特征及对三峡贯通的示踪意义

理论分析表明,碎屑钾长石Pb同位素在大河流域沉积物物源示踪及追索河流演化研究中具有独特意义。近年来,随着
单颗粒碎屑矿物微区分析技术的快速发展,碎屑钾长石Pb同位素已成为一种有效的物源示踪方法,在判别沉积物物源、重建古水
系等方面已得到了较好的应用,同时沉积物全岩的Pb同位素能对碎屑钾长石Pb同位素的示踪起到一定的补充作用。通过对长
江流域不同河段和支流流域钾长石及全岩Pb同位素的空间分异特征的即可识别性分析、河流地貌和水文特性对源-汇之间物质
的可通达性分析以及流域地质环境条件的分析,认为利用Pb同位素方法来示踪江汉盆地不同时期沉积物的源区,并重建长江水
系的演化过程是可行的。最后对开展此项研究的思路进行了讨论。      

Long-term monitoring revealed fish assemblage zonation in the Three Gorges Reservoir

Reservoirs are important artificial ecosystems that modify the hydrological and ecological characteristics of a river.Knowledge of the basic characteristics of fish assemblages in reservoirs is a first step toward the development of effective conservation policies.We used the information collected over a10-year period(2006-2015)to assess the structure of the fish assemblages in the Three Gorge Reservoir(TGR)in a river-dam gradient.Three fish zones were detected in TGR.Species richness was the highest in the upper zone and lowest in the lower zone.The riverine zones were dominated by rheophilic species Coreius guichenoti and Pelteobagrus vachelli.The transitional zones were dominated by Coreius heterodon and Rhinogobio cylindricus.The lacustrine zones were dominated by eurytopic species Hypophthalmichthys molitrix,Aristichthys nobilis,Hemiculter bleekeri and Cyprinus carpio.For the functional characteristics,fish assemblages in riverine and transitional zones were dominated by insectivorous species,equilibrium strategists and rheophilic species(e.g.,Coreius heterodon and Coreius guichenoti).In lacustrine zones,the fish assemblage was dominated by habitat generalists common to lakes and reservoirs(e.g.,Hemiculter bleekeri,Hypophthalmichthys molitrix,Aristichthys nobilis).Moreover,18 exotic species(e.g.,Protosalanx hyalocranius,Ictalurus punctatus,Megalobrama amblycephala,Tilapia)were collected in TGR,most of which only existed in the lacustrine zone.The results highlight the importance of freely flowing riverine reaches for conserving native fish in the upper Changjiang River and adaptive management strategies for fisheries in TGR.     

长江三峡库区(奉节-巴东段)移民工程遥感动态监测

在长江三峡库区移民工程中 ,我们采用 ETM+、SPOT、IKONOS等多源、多时相、多分辨率航天、航空遥感数据组合 ,监测移民工程的动态变化 ,通过对库区奉节 -巴东段移民搬迁建与安置、新开发用地分布、土地利用与土地结构变化、地质灾害及衍生地质灾害与防治、库区环境及生态平衡与改善经济结构以及移民工程遥感动态监测等 ,取得突破性进展 ,获取了一批重要成果。为三峡移民工程进一步全面、安全地实施、改进规划管理工作及库区经济可持续发展 ,提供了科学依据和决策性建议。     

Size-fractionated phytoplankton biomass in autumn of the Changjiang （Yangtze） River Estuary and its adjacent waters after the Three Gorges Dam construction

A cruise was undertaken from 3rd to 8th November 2004 in Changjiang （Yangtze） River Estuary and its adjacent waters to investigate the spatial biomass distribution and size composition of phytoplankton. Chlorophyll-a （Chl-a） concentration ranged 0.42-1.17 μg L^-1 and 0.41-10.43 μg L^-1 inside and outside the river mouth, with the mean value 0.73 μg L^-1 and 1.86 μg L^-1, respectively. Compared with the Chl-a concentration in summer of 2004, the mean value was much lower inside, and a little higher outside the river mouth. The maximal Chl-a was 10.43 μg L^-1 at station 18 （122.67°E, 31.25°N）, and the region of high Chl-a concentration was observed in the central survey area between 122.5°E and 123.0°E. In the stations located east of 122.5°E, Chl-a concentration was generally high in the upper layers above 5 m due to water stratification. In the survey area, the average Chl-a in sizes of 〉20 μm and 〈20 μm was 0.28 μg L^-1 and 1.40 μg L^-1, respectively. High Chl-a concentration of 〈20 μm size-fraction indicated that the nanophytoplankton and picophytoplankton contributed the most to the biomass of phytoplankton. Skeletonema costatum, Prorocentrum micans and Scrippsiella trochoidea were the dominant species in surface water. The spatial distribution of cell abundance of phytoplankton was patchy and did not agree well with that of Chl-a, as the cell abundance could not distinguish the differences in shape and size of phytoplankton cells. Nitrate and silicate behaved conservatively, but the former could probably be the limitation factor to algal biomass at offshore stations. The distribution of phosphate scattered considerably, and its relation to the phytoplankton biomass was complicated.     

大江筑坝敢为先--长江三峡工程地质勘察历史回顾

峡工程是我国正在建设中的一座特大型水利枢纽工程。大坝建在湖北省宜昌市夷陵区三斗坪镇,坝顶标高185米,坝基标高约4米;设计正常高水位175米,水库回水至重庆市江津县,水库全长667公里,水库总库容393亿立方米,其中防洪库容221亿立方米;电站装机26台,总容量1820万千瓦;设有五级船闸与升船机,年单向通航能力5000万吨。有巨大的防洪、     

基于多源数据的长江经济带内河港口区位优势度评估

内河港口是内河航运纽带的重要节点,评估内河港口的区位优势度对长江经济带港口基础设施建设等具有重要意义。以2021年长江沿岸内河港口为研究对象,采用多源数据,结合长江内河港口辐射范围内的3个指标并对原模型进行改进,结合AHP-EWM模型计算长江经济带长江沿岸28个港口的区位优势度,研究结果显示：① 除重庆和武汉以外,江苏省以外的其他省份港口辐射范围内交通网络密度都比较低;从交通干线影响度来看,分布比较均衡且数值较为相近;而城市经济影响力的空间分布较为无序;② 根据区位优势度的高低以及空间分布得出长江经济带货运港口空间格局为“三中心,一组团”的空间格局;③ 将内河港口按长江岸线所属省份进行划分后发现：江西省3个港口区位优势度差异最小,但其优势度也整体偏低;安徽省与江西省类似;江苏省整体优势度较高且差异小,湖北省的优势度差异最大,表明存在基础设施建设不均衡等问题且亟需改善。研究成果可对长江经济带内各个港口范围内基础设施建设、道路交通规划、港口选址等方面提供指导性意见帮助打通铁路、高等级公路进港“最后一公里”。     

三峡重庆地区钻孔应变资料可靠性检验与分析

对三峡重庆地区6个四分量钻孔应变资料进行可靠性分析,利用其增量观测数据进行相对标定,得到各站点测区的应变参数,并分析测区相对应变特征。结果表明,6个站点的钻孔应变观测资料是可靠的,其中1个站点测区面应变呈现张性变化,靠近三峡库首区的5个站点测区面应变呈现压性变化,测点主压应变方向与大范围构造应力场方向较为一致,表明三峡重庆地区呈现压性特征。     

三峡库区典型样带潜热通量遥感反演与验证

本文以三峡库区腹地的部分地区为典型样带,利用遥感数据的时效性和区域性优势,结合常规气象数据,定量反演样带地表潜热通量,并对比验证遥感反演方法的可行性和可靠性。结果表明：潜热通量在不同地表覆被状况下呈现较大差异,城镇居民区和无植被覆盖区一般在20~80W·m^-2;人工林场、山区森林及草灌和山前农作区在180~280W·m^-2;水体则分布在420~470W·m^-2,潜热通量整体呈现出随地表覆被变化而变化的空间异质性。此外,由于库区地表覆被类型多样,并受到山区起伏地形地貌的影响,潜热通量在空间分布上的地形分异特征也较显著。     

宜昌地区第四纪沉积物中玄武岩砾石特征及其与长江三峡贯通的关系

通过对宜昌地区第四纪沉积物中峨眉山玄武岩砾石的寻找和研究,可以确定三峡以西物质搬运至宜昌地区的时间,从而为长江三峡贯通时间的确定提供参考。在详细研究宜昌地区第四纪沉积物的沉积特征和沉积相基础上,分析不同沉积环境、不同时代沉积物中玄武岩质砾石的岩石学、稀土及微量元素特征,从而发现0.7Ma以前云池组和善溪窑组的扇三角洲及湖相沉积物中,不存在来自三峡西侧的峨眉山玄武岩,而在0.7 Ma以后的阶地沉积及现代河床中却可以找到该玄武岩砾石。结果表明,在0.7 Ma以前不存在贯通三峡的长江。