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1.
为保留目标的同时尽可能多地抑制图像背景杂波,在研究形态学滤波、空域平滑滤波、小波域平滑滤波以及它们级联的背景杂波抑制算法的基础上,提出形态学滤波和小波域平滑滤波级联的杂波抑制算法。该算法先对含有微弱目标和白高斯噪声的原始图像进行空域形态学滤波,然后对形态学滤波结果进行小波变换,在小波域中对各小波系数分别平滑滤波,用滤波前的小波系数减去滤波后的小波系数得到差值系数,对差值系数再进行逆小波变换。仿真测试表明,提出的算法在得到的残差图像中目标邻域信杂比(SCNR)平均增益比空域形态学滤波算法和空域平滑滤波算法等均有较明显的提高,为后续的目标检测与跟踪提供了良好的保障。  相似文献   

2.
黑龙江(又称为阿穆尔河)是中国和俄罗斯之间的国际界河,近年来洪水事件频发,给流域内中俄两国带来巨大的人口伤亡和经济损失,加强该流域的洪水监测是两国面临的共同紧迫需求。传统的光学遥感影像受制于洪水期间多云多雨的天气状况,难以及时获得无云影像。本文充分利用全天候雷达数据的优势,提出了一种基于哨兵1号(Sentinel-1)合成孔径雷达数据监测大面积区域洪水的方法。通过Gamma分布和高斯分布拟合SAR影像后向散射系数的概率密度分布,迭代后验概率差值,自动获得全局阈值来分割初始的水体,基于辅助数据细化去除了初始水体中与水体相似的误分类型,并由形态学操作后处理提高了提取的洪水的均匀性。结果表明:(1)与传统的分割算法相比,本文提出的方法基于SAR影像后向散射系数的分布规律进行概率密度函数分段拟合,将全局统计划分为局部关系,显著地改善了常规分割算法在水体和非水体像素量级相差过大而表现不佳的情况;(2)研究获得了2017—2020年逐年的洪水分布,结果总体精度在87.78%~94.89%之间,Kappa系数在0.76~0.89之间;(3)特别是对于大面积半干旱地区,本文结合了后向散射特性、地形和其...  相似文献   

3.
Mangroves accumulate sedimentary sequences, where cores can provide historical records of mangrove evolution with past climate change and human activity. The study traced the history of mangrove evolution during the past one hundred years in a mangrove swamp of Maowei Sea, SW China. The sedimentation rates(0.38-0.95 cm yr~(-1)) were calculated on the basis of ln(~(210)Pb_(xs)/Al) and mass depth in the core sediments. Chemical tracers, such as δ~(13)C_(org) and C:N values, were utilized to trace the contribution of mangrove-derived organic matter using a ternary mixing model. Because of potential diagenetic alteration and / or overlap in the isotopic signatures of different components, simultaneous use of mangrove pollen diagrams can help to supplement some of these limitations. Combined with mangrove pollen, mangrove evolution was reconstructed and could be divided into three stages: flourishment(1886-1905 AD), slight degradation(1905-1949 AD) and rapid degradation period(1949-2007 AD), which was consistent with previous reports. The reclamation of mangrove swamps to shrimp ponds was the major reason for rapid degradation of mangrove ecosystems in recent years, rather than climate change in the region.  相似文献   

4.
Hexi region is located in the northwest arid zone in China, being both the base of industry and agriculture, and the prop of developing northwestern China on a large scale in the next century. On the basis of the study on exploitation and utilization process of water and land resources in past 40 years, and present productivity, this paper approaches the utilization trend and development potential of water and land resources; analyses the characteristics, problems and directions of resource utilization in the future; and proposes the countermeasures of rational development of water and land resources.  相似文献   

5.
ThecontiguousregionofJiangsu,Shandong,HenanandAnhuiprovinces,withapopulationof4660X10'in1990,stretchingalongtheChina'seasternsectionofeconomicbeltofnewEurasialxindBridge,issituatedinthenortheasternpartoftheHuaiheRiverBasin,covering7.73X10'km'ofnineprefecturesormunicipalities,i.e.,XuzhouandLianyungangofJiangsuProvince,Rizhao,Linyi,ZaozhuangandJiningofShandongProvince,ShangqiuofHenanProvince,HuaibeiandSuxianofAnhuiProvince.Theregionisatraditionalagricultureareaandanimportantenergybase…  相似文献   

6.
Coordinated and sustainable development of farmers, agriculture and countryside (FAC) is key to realize the national objective of comprehensively developed well-off society. Since the peaceful liberation of Tibet, outstanding achievements have been made in FAC work. However, compared with East and Middle China, there still exists a big gap. The farmers‘ net income per capita in 2001 was 1,404 yuan, 962 yuan lower than the nation‘s average. In late 90‘s the farmers‘ income growth slowed down. Agricultural industrialization is at low level, technologies play a small role in agricultural development, rural infrastructure is weak, the rural grass root organization is much underdeveloped, and construction of towns is behind the other regions of China. Based on the problems of FAC development there, this paper proposes FAC development strategies and measures for accelerating rural development in Tibet.  相似文献   

7.
塔里木盆地寒武系白云岩储层具有年代老、埋深大、成岩作用强烈的特征,原生孔隙几乎被破坏殆尽,有效裂缝的发育程度是决定储层优劣的关键因素。根据岩芯描述、薄片鉴定、FMI成像测井、扫描电镜、阴极发光、电子探针以及流体包裹体分析等研究手段,开展了塔里木盆地北部地区(简称"塔北地区")寒武系白云岩储层的裂缝充填特征及有效性分析。塔北地区整体裂缝发育,天山南地区与塔河地区裂缝在产状、线密度、形态以及充填特征上存在差异。天山南地区裂缝线密度与有效性均低于塔河地区,充填矿物主要为自形白云石与石英,其次为方解石、石膏与黄铁矿。充填白云石分为3期,对应的温度区间分别为70℃~90℃、90℃~110℃及110℃以上,均为地层内的成岩流体成因;充填石英分两期,第一期为黏土矿物转化蚀变形成,第二期可能为热液成因。塔河地区裂缝线密度高,有效性较好,溶蚀作用发育,是有利的勘探地区,其充填物以热液矿物组合形式出现,主要为方解石,其次为石膏、鞍状白云石、黏土矿物、沥青等,重晶石以交代白云石的形式出现。充填方解石分为4期,对应的温度区间分别为70℃~100℃、100℃~130℃、130℃~180℃及180℃以上,前3期充填为不同埋深时期地层内成岩流体成因,最后一期充填为自下部运移而来的高温热液流体成因。  相似文献   

8.
泰山玉是近年来在泰山西麓作为玉矿勘查并开发的一种蛇纹石质玉石,赋存于镁质超基性岩变质成因的蛇纹岩体中。矿区共有4个矿体,按玉化程度不同,组成矿体的蛇纹岩可分为碧玉、墨玉、未玉化蛇纹岩。通过对不同矿体和不同玉化程度的矿石进行系统采样分析,按玉化程度(碧玉、墨玉、未玉化蛇纹岩),对其主要化学成分的变化进行了系统对比,发现玉化进程中Si O_2含量与TFe和LOI含量的变化呈负相关性,即随着玉化程度的提高,Si O_2含量增加,TFe和LOI含量减少,呈现出TFe和LOI主要被Si O_2置换的特征,使蛇纹岩到玉石由不透明逐渐变得透明,颜色由灰黑—黑色变为较鲜艳的深绿、黄绿等更美丽的色彩,玉质变得更加细腻油润,玉石硬度得到提高。  相似文献   

9.
The relationships between the neon flying squid, Ommastrephes bartrami, and the relative ocean environmental factors are analyzed. The environmental factors collected are sea surface temperature (SST), chlorophyll concentration (Chl-a) and sea surface height (SSH) from NASA, as well as the yields of neon flying squid in the North Pacific Ocean. The results show that the favorable temperature for neon flying squid living is 10°C–22°C and the favorite temperature is between 15°C–17°C. The Chl-a concentration is 0.1–0.6 mg/m3. When Chl-a concentration changes to 0.12–0.14 mg/m3, the probability of forming fishing ground becomes very high. In most fishing grounds, the SSH is higher than the mean SSH. The generalized additive model (GAM) was applied to analyze the correlations between neon flying squid and ocean environmental factors. Every year, squids migrate northward from June to August and return southward during October–November, and the characteristics of the both migrations are very different. When squids migrate to the north, most relationships between the yields and SST are positive. The relationships are negative when squids move to southward. The relationships between the yields and Chl-a concentrations are negative from June to October, and insignificant in November. There is no obvious correlation between the catches of squid and longitude, but good with latitude. Supported by the National High Technology Research and Development Program of China (863 Program, No. 2003AA607030); National Key Technology Research and Development Program (No. 2006BAD09A05)  相似文献   

10.
The relationships between the neon flying squid, Ommastrephes bartrami, and the relative ocean environmental factors are analyzed. The environmental factors collected are sea surface temperature (SST), chlorophyll concentration (Chl-a) and sea surface height (SSH) from NASA, as well as the yields of neon flying squid in the North Pacific Ocean. The results show that the favorable temperature for neon flying squid living is 10℃-22℃ and the favorite temperature is between 15℃-17℃. The Chl-a concentration is 0.1-0.6 mg/m3. When Chl-a concentration changes to 0.12-0.14 mg/m3, the probability of forming fishing ground becomes very high. In most fishing grounds,the SSH is higher than the mean SSH. The generalized additive model (GAM) was applied to analyze the correlations between neon flying squid and ocean environmental factors. Every year, squids migrate northward from June to August and return southward during October-November, and the characteristics of the both migrations are very different. When squids migrate to the north, most relationships between the yields and SST are positive. The relationships are negative when squids move to southward. The relationships between the yields and Chl-a concentrations are negative from June to October, and insignificant in November. There is no obvious correlation between the catches of squid and longitude, but good with latitude.  相似文献   

11.
The relatively rapid recession of glaciers in the Himalayas and formation of moraine dammed glacial lakes(MDGLs) in the recent past have increased the risk of glacier lake outburst floods(GLOF) in the countries of Nepal and Bhutan and in the mountainous territory of Sikkim in India. As a product of climate change and global warming, such a risk has not only raised the level of threats to the habitation and infrastructure of the region, but has also contributed to the worsening of the balance of the unique ecosystem that exists in this domain that sustains several of the highest mountain peaks of the world. This study attempts to present an up to date mapping of the MDGLs in the central and eastern Himalayan regions using remote sensing data, with an objective to analyse their surface area variations with time from 1990 through 2015, disaggregated over six episodes. The study also includes the evaluation for susceptibility of MDGLs to GLOF with the least criteria decision analysis(LCDA). Forty two major MDGLs, each having a lake surface area greater than 0.2 km2, that were identified in the Himalayan ranges of Nepal, Bhutan, and Sikkim, have been categorized according to their surface area expansion rates in space and time. The lakes have been identified as located within the elevation range of 3800 m and6800 m above mean sea level(a msl). With a total surface area of 37.9 km2, these MDGLs as a whole were observed to have expanded by an astonishing 43.6% in area over the 25 year period of this study. A factor is introduced to numerically sort the lakes in terms of their relative yearly expansion rates, based on their interpretation of their surface area extents from satellite imageries. Verification of predicted GLOF events in the past using this factor with the limited field data as reported in literature indicates that the present analysis may be considered a sufficiently reliable and rapid technique for assessing the potential bursting susceptibility of the MDGLs. The analysis also indicates that, as of now, there are eight MDGLs in the region which appear to be in highly vulnerable states and have high chances in causing potential GLOF events anytime in the recent future.  相似文献   

12.
We sampled the sediments of the East China Sea during 2005 and 2006, and analysed the contents of the biogenic mat-ters: biogenic silica, organic carbon, and organic nitrogen. From the surface distribu...  相似文献   

13.
21世纪高校GIS本科人才培养方案的研究   总被引:17,自引:3,他引:17  
地理信息系统专业是一个新办专业,就目前而言,从教学计划、教学大纲、课程设置、教材的系统建设等方面都还存在问题。主要从GIS本科的培养目标计划、课程体系建设、实践教学及教与学的关系等方面阐述了思想,以与大家探讨如何建设一个规范、成熟的地理信息系统专业。  相似文献   

14.
The monthly mean suspended sediment concentration in the upper layer of the East China Seas was derived from theretrieval of the monthly binned SeaWiFS Level 3 data during 1998 to 2006.The seasonal variation and spatial distribution of thesuspended sediment concentration in the study area were investigated.It was found that the suspended sediment distribution presentsapparent spatial characteristics and seasonal variations,which are mainly affected by the resuspension and transportation of the sus-pended sediment in the study area.The concentration of suspended sediment is high inshore and low offshore,and river mouths aregenerally high concentration areas.The suspended sediment covers a much wider area in winter than in summer,and for the samesite the concentration is generally higher in winter.In the Yellow and East China Seas the suspended sediment spreads farther to theopen sea in winter than in summer,and May and October are the transitional periods of the extension.Winds,waves,currents,ther-mocline,halocline,pycnocline as well as bottom sediment feature and distribution in the study area are important influencing factorsfor the distribution pattern.If the 10mg L-1 contour line is taken as an indicator,it appears that the transportation of suspended sedi-ment can hardly reach 124°00'E in summer or 126°00'E in winter,which is due to the obstruction of the Taiwan Warm Current andthe Kuroshio Current in the southern Yellow Sea and the East China Sea.  相似文献   

15.
近年来,有机质与金属成矿关系研究备受关注.扬子板块北缘马元矿床铅锌矿体分布与古油藏、沥青在空间上叠置,是探索有机质与铅锌成矿关系的理想地区.矿区发育分散有机质、沥青、气态烃类等不同赋存形式的有机质,生物标志化合物特征明显,以低碳数正构烷烃为主,具浅海环境藻类来源特征,均处于过成熟演化程度.沥青206Pb/204Pb值为...  相似文献   

16.
青藏高原北缘公格尔山地区地形梯度的剖析   总被引:2,自引:0,他引:2  
本文以青藏高原北缘西昆仑山脉的公格尔山地区为试验区域,基于SRTM-DEM数据,采用线状地形剖面和带状地形剖面的研究方法,对试验区从公格尔山顶到塔里木盆地的地形梯度进行了研究,并探讨了地形梯度与隆升过程之间的关系。研究结果表明:(1)线状地形剖面清晰直观,操作简单;带状剖面法能较好地反映区域的地形起伏状况。若将两种方法联合起来共同进行区域地形研究,则会获得更好效果。(2)从塔里木盆地到公格尔山顶,地形抬升共分3个梯度:分别是从海拔高度2 000m左右上升到约4 500m,从约4 500m上升到将近6 000m,从将近6000m上升到约7500m。地形抬升的不同梯度可能对应着公格尔山晚新生代地貌形成过程的不同隆升过程;而每个抬升梯度的拐点,则对应着不同隆升过程形成海拔高度的分界点。  相似文献   

17.
充分认识山东省土地资源利用所面临的形势,是保障经济社会新旧动能有序转换的基本问题。土地资源与新旧动能转换存在着相互渗透、相互促进的关系,土地资源以宏观调控的方式,促进新旧动能的有序转换,是保障新旧动能有序转换的有效手段;新旧动能转换又是土地资源管理、利用和保护的内在需求。该文从新旧动能转换基本概念出发,深入剖析了二者之间的相互关系,从土地利用方式、土地利用结构和布局、土地质量和土地生态环境四个方面,分析了新旧动能转换对土地保障能力的要求,探究了土地资源利用管理中的旧动能和新动能,总结归纳土地资源管理、利用和保护对经济发展的新旧动能转换的作用,提出了保障新旧动能有序转换的措施。  相似文献   

18.
北宋文化吸纳了前此数千年的历史积淀 ,而皮毛落尽 ,精神独存 ,不仅各个文化领域、各类文化形式、各种雅俗文化百花齐放 ,更以独树一帜的北宋文化精神卓然自立。苏轼的诗歌正是在北宋这一特定历史时期的文化背景下孕育成长起来的。作为中国传统文化最具典型性的“文人”代表 ,苏轼通过其二千七百余首包赡丰富、变化万状的诗作 ,展现出了一幅北宋文化绚丽多彩的历时性的“清明上河图”。尤其引起我们注意的是 ,北宋文化精神中最为突出的两个方面———议论精神和淡雅精神 ,对苏轼诗歌产生了更为直接、更为深刻的影响 ,而苏诗的议论化和崇雅尚淡倾向又更为突出、更为集中、更为典型地代表了北宋文化的议论精神和淡雅精神  相似文献   

19.
Road network is a critical component of public infrastructure,and the supporting system of social and economic development.Based on a modified kernel density estimate(KDE)algorithm,this study evaluated the road service capacity provided by a road network composed of multi-level roads(i.e.national,provincial,county and rural roads),by taking account of the differences of effect extent and intensity for roads of different levels.Summarized at town scale,the population burden and the annual rural economic income of unit road service capacity were used as the surrogates of social and economic demands for road service.This method was applied to the road network of the Three Parallel River Region,the northwestern Yunnan Province,China to evaluate the development of road network in this region.In results,the total road length of this region in 2005 was 3.70×104km,and the length ratio between national,provincial,county and rural roads was 1∶2∶8∶47.From 1989 to 2005,the regional road service capacity increased by 13.1%,of which the contributions from the national,provincial,county and rural roads were 11.1%,19.4%,22.6%,and 67.8%,respectively,revealing the effect of′All Village Accessible′policy of road development in the mountainous regions in the last decade.The spatial patterns of population burden and economic requirement of unit road service suggested that the areas farther away from the national and provincial roads have higher road development priority(RDP).Based on the modified KDE model and the framework of RDP evaluation,this study provided a useful approach for developing an optimal plan of road development at regional scale.  相似文献   

20.
“一带一路”倡议是新时期中国为加强对外开放提出的全球化合作倡议,资源环境的优化配置对全球化发展意义重大。气温作为重要的基础数据和输入要素,对其进行空间化处理是实现大尺度区域资源环境优化配置的前提。本文基于地理信息技术(GIS),运用距离平方反比法(IDS)、协同克里格法(CK)、回归距离平方反比法(RIDS)和回归协同克里格法(RCK),对“一带一路”地区1980—2017年的2679个气象站点的月平均气温和年平均气温数据进行插值,获得了“一带一路”地区10 km分辨率的气温空间分布数据。交叉验证结果表明:① IDS、CK、RIDS和RCK插值法在整体上均较好地展示了“一带一路”地区气温的地理空间分布规律,4种插值方法的月均气温的均方根误差分别在1.93~2.43、1.78~2.14、1.31~2.23和1.23~1.92 ℃之间;年均气温的均方根误差分别为1.94、1.83、1.37和1.27 ℃;② 在“一带一路”地区,加入协变量分析的CK插值精度整体优于IDS,并且削弱了IDS的极值现象;③ RIDS和RCK对年均气温的插值精度分别较IDS和CK提高了29.4%和30.6%,表明加入地理要素并进行残差修正的插值精度得到了进一步提高。总体来看,RCK插值法对气温数据的插值精度最高,可以考虑将此方法作为“一带一路”地区温度等气象要素的插值方法。  相似文献   

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