基于随机森林的第三次国土调查可行性分析——以水体为例     

蔡宗磊  刘明松  苗正红  常雪  刘艳慧 《测绘与空间地理信息》2021,44(3):33-35

全国第三次国土调查的一个重要步骤为内业勾绘图斑,需要大量的人力、物力及财力来支撑.利用目视解译的方法进行内业图斑的勾绘,不仅费时费力,而且需要作业人员具有一定的遥感图像解译经验从而满足图斑勾绘的进度及精度.因而,针对全国第三次国土调查,本文基于随机森林的分类方法探讨遥感图像分类的精度是否可以满足全国第三次国土调查图斑勾绘的精度,主要以水体为例.通过利用目视解译的成果来验证随机森林分类的精度,结果表明,随机森林分类的总体精度为91.45％,Kappa系数为0.66,因而,利用随机森林的分类方法可以满足全国第三次国土调查的精度,并且可以精度较高地提取遥感图像中的水体.  相似文献   

2010年玉树7.1级地震诱发滑坡特征及其地震地质意义   总被引：3，自引：0，他引：3  

蒋瑶  吴中海  李家存  马丹  周春景  李跃华  刘艳辉 《地质学报》2014,88(6):1157-1176

2010年玉树7.1级地震造成了一系列次生地质灾害。笔者在玉树灾区地震地质灾害调查基础上,结合Quickbird高分辨率遥感影像数据和航片影像数据,以目视解译为主,共提取了542处地震滑坡,并首次发现了11处古地震滑坡。调查研究结果显示,玉树地震滑坡主要包括崩塌、狭义的滑坡和土溜等三种类型。其中地震崩塌占到了90%以上,按其物质成分可进一步划分为碎屑型崩塌、碎屑流型崩塌和岩崩等三类。地震滑坡的空间展布特征显示,该区80%以上的地震滑坡集中分布在以玉树活动断层为轴的长约95km、两侧宽2km的廊带区内,并与发震断层距离和宏观震中有很好的相关性,其高密度区与同震地表破裂的空间分段性也有很好的对应关系,体现出典型的走滑型发震断层的控灾特点。同时,还进一步分析了山体坡度、坡体形态、临空面高度和地层岩石与岩体完整度等因素对地震滑坡总体分布的影响。对古地震滑坡的初步研究发现,古地震滑坡的规模、期次和分布特征间接地反映出玉树断裂带在全新世期间曾发生过多次震级强度明显大于本次玉树7.1级地震的古地震事件,这为更深入探索玉树断裂带古地震事件提供了另一种重要的研究途径。此外,地震滑坡分布与地表破裂和极震区破坏程度之间的密切空间关系指示,地震滑坡也可以成为快速圈定宏观震中以及开展极震区地震烈度评价等方面的重要指标。  相似文献   

The impact of surface energy exchange on the thawing process of active layer over the northern Qinghai–Xizang Plateau,China     

Ren Li  Lin Zhao  Tonghua Wu  Yongjian Ding  Yao Xiao  Guojie Hu  Defu Zou  Wangping Li  Wenjun Yu  Yongliang Jiao  Yanhui Qin 《Environmental Earth Sciences》2014,72(6):2091-2099

In this study, we collected radiation and active layer temperature data observed in the northern Qinghai–Xizang Plateau during the period 2006–2008 in order to analyze the impact of surface energy balance on the thawing process of the active layer. Results show that surface energy exhibits an obvious seasonal variation. The largest values of energy variables including global radiation, net radiation, soil heat flux and surface heat source intensity occur during June and July, while the smallest values occur in November and December. The active layer is generally dominated by an endothermic process. During the freeze–thaw period, the variation process of the active layer temperature is similar to that of surface energy. The seasonal thawing depth is closely related to the process of surface energy exchange. During the thawing period, seasonal thawing depth gradually increases as more solar energy enters the surface. When the surface energy accumulation is 0.0 MJ m^?2 d^?1, the seasonal thawing depth is the smallest. The seasonal thawing depth gradually increases with further accumulation of surface energy. Thus, the variation processes between the surface energy and seasonal thawing depth can be expressed by a power relation. The values of seasonal thawing depth calculated with the empirical relationship provided in this study agree well with the observed values. The relative error between calculated and observed values is less than 12 %. These results show that this empirical relationship can be successfully used to describe the behavior of active layers.  相似文献   

Removal of bisphenol A from aqueous solution using cetylpyridinium bromide (CPB)-modified natural zeolites as adsorbents     

Jia Li  Yanhui Zhan  Jianwei Lin  Ai Jiang  Wang Xi 《Environmental Earth Sciences》2014,72(10):3969-3980

Surfactant-modified natural zeolites (SMNZs) with different coverage types were prepared by loading cetylpyridinium bromide onto the surface of natural zeolites. The resulting SMNZs were characterized and used as adsorbents to remove bisphenol A (BPA) from aqueous solution. The monolayer and bilayer SMNZs were effective for removing BPA from aqueous solution. The BPA adsorption capacity for the monolayer SMNZ increased slightly with increasing pH from 4 to 9, but decreased significantly with increasing pH from 9 to 11. The BPA adsorption capacity for the bilayer SMNZ was relatively high at pH 9–10, but decreased with decreasing pH from 9 to 4 or increasing pH from 10 to 11. The equilibrium adsorption data of BPA on the monolayer and bilayer SMNZs under the experimental condition could be well described by the Langmuir and Freundlich isotherm models. The adsorption kinetics of BPA on the monolayer and bilayer SMNZs followed a pseudo-second-order model. The adsorption of BPA on the monolayer and bilayer SMNZs took place in three different stages: a fast external surface adsorption, a gradual adsorption controlled by both the external mass transfer and the intra-particle diffusion, and a final equilibrium stage. The adsorption of BPA on the monolayer and bilayer SMNZs is spontaneous and exothermic. The mechanisms for BPA adsorption onto the monolayer SMNZ at pH 4–11 include the hydrophobic interaction and hydrogen bonding. The mechanisms for BPA adsorption onto the bilayer SMNZ at pH 4–8 include the organic partitioning and hydrogen bonding. The mechanisms for BPA adsorption onto the bilayer SMNZ at pH 8–11 include the organic partitioning, hydrogen bonding and electrostatic attraction.  相似文献   

基于离散裂隙网络模型的核素粒子迁移数值模拟研究   总被引：1，自引：1，他引：0       下载免费PDF全文

魏亚强  董艳辉  周鹏鹏  王礼恒  宋凡 《水文地质工程地质》2017,(1):123-130

高放废物地质处置过程中涉及的核素在围岩裂隙地下水中的迁移问题已引起广泛关注,数值模拟是研究核素粒子运移的重要方法。目前裂隙介质中渗流模型主要是等效连续介质模型、双重介质模型和离散裂隙网络模型。对于岩体尺度裂隙地下水的流动,离散裂隙网络模型能充分表现裂隙介质的各向异性、不连续性等特征。因此,针对裂隙介质准确概化及核素迁移模拟等难点,文章结合Monte Carlo随机生成裂隙方法、裂隙渗流有限元算法和高放射性核素衰变方程等方法,依据花岗岩深钻孔裂隙统计数据,采用离散裂隙网络模型对内蒙古阿拉善高放废物地质处置预选区展开了核素粒子迁移数值模拟研究,并讨论了实例预测分析结果。结果显示:针对设定的地质模型,核素粒子从中心运移到边界的迁移路径长度平均为1293.35 m,粒子运移到边界耗费的时间平均为1.70E+11 d。  相似文献   

Mantle source heterogeneity and magmatic evolution at Carlsberg Ridge (3.7°N): constrains from elemental and isotopic (Sr,Nd, Pb) data     

Ling Chen  Limei Tang  Xing Yu  Yanhui Dong 《Marine Geophysical Researches》2017,38(1-2):47-60

We present new major element, ICP-MS trace element, and Sr–Nd–Pb isotope data of basalts from four locations along the Carlsberg Ridge (CR), northern Indian Ocean. The basalts are low-K tholeiites with 7.52–9.51 wt% MgO, 49.40–50.60 wt% SiO₂, 0.09–0.27 wt% K₂O, 2.55–2.90 wt% Na₂O, and 0.60–0.68 Mg^#. Trace element contents of the basalts show characteristics similar to those of average normal MORB, such as LREE depleted patterns with (La/Sm)_N ratio of 0.55–0.69; however, some samples are enriched in large-ion lithophile elements such as K and Rb, suggesting probable modification of the mantle source. Poor correlations between the compatible elements [e.g. Ni, Cr, and Sr (related to olivine, clinopyroxene and plagioclase, respectively)] and the incompatible elements (e.g. Zr and Y), and positive correlations in the Zr versus Zr/Y and Nb versus Nb/Y plots suggest a magmatic evolution controlled mainly by mantle melting rather than fractional crystallization. Our results extend the CR basalt range to higher radiogenic Pb isotopes and lower ¹⁴³Nd/¹⁴⁴Nd. These basalts and basalts from the northern Indian Ocean Ridge show lower ¹⁴³Nd/¹⁴⁴Nd and higher ⁸⁷Sr/⁸⁶Sr values than those of the depleted mantle (DM), defining a trend towards pelagic sediment composition. The Pb isotopic ratios of basalts from CR 3–4°N lie along the compositional mixing lines between the DM and the upper continental crust. However, the low radiogenic Pb of basalts from CR 9–10°N lie on the mixing line between the DM and lower continental crust. Since the Pb isotopic ratio of MORB would decrease if the source mantle was contaminated by continental lithospheric mantle, we suggest that CR contains continental lithospheric material, resulting in heterogeneous mantle beneath different ridge segments. The continental lithospheric material was introduced into the asthenosphere before or during the breakup of the Gondwana. These results support the long-term preservation of continental material in the oceanic mantle which would significantly influence the isotopic anomaly of the Indian Ocean MORB.  相似文献   

Using fuzzy theory and variable weights for water quality evaluation in Poyang Lake,China   总被引：1，自引：0，他引：1  

Bing Li  Guishan Yang  Rongrong Wan  Lu Zhang  Yanhui Zhang  Xue Dai 《中国地理科学(英文版)》2017,27(1):39-51

Achieving water purity in Poyang Lake has become a major concern in recent years, thus appropriate evaluation of spatial and temporal water quality variations has become essential. Variations in 11 water quality parameters from 15 sampling sites in Poyang Lake were investigated from 2009 to 2012. An integrative fuzzy variable evaluation(IFVE) model based on fuzzy theory and variable weights was developed to measure variations in water quality. Results showed that: 1) only chlorophyll-a concentration and Secchi depth differed significantly among the 15 sampling sites(P 0.01), whereas the 11 water quality parameters under investigation differed significantly throughout the seasons(P 0.01). The annual variations of all water quality variables except for temperature, electrical conductivity, suspended solids and total phosphorus were considerable(P 0.05). 2) The IFVE model was reasonable and flexible in evaluating water quality status and any possible ′bucket effect′. The model fully considered the influences of extremely poor indices on overall water quality. 3) A spatial analysis indicated that anthropogenic activities(particularly industrial sewage and dredging) and lake bed topography might directly affect water quality in Poyang Lake. Meanwhile, hydrological status and sewage discharged into the lake might be responsible for seasonal water quality variations.  相似文献   

多层次多粒度OSM路网目标数据质量综合评估方法研究     

朱富晓  王艳慧 《地球信息科学学报》2017,19(11):1422-1432

针对以往OpenStreetMap（OSM）数据质量评价中只考虑片面评价指标或只考虑单一层次评估对象的不足,本文选取典型研究区,以来自政府规划机构的权威数据集作为参照数据,基于模糊综合评价法,设计了质量评价指标与空间层次相结合的多层次多粒度OSM路网目标数据质量评估模型,从单一目标、群组目标和整体目标3个粒度,集成构建集个体数量控制与群体结构控制于一体的数据质量评估指标体系,并解决评估模型中隶属度确定与最优组合权重赋权的关键技术问题,实现了宏观与微观相结合、全局与局部相结合的OSM数据质量的多维度多层次综合度量。实验结果表明,该方法具有可行性和实用性,可为基于VGI数据源实现相关行业应用提供实证依据和可靠的数据质量评估方法。  相似文献   

微板块构造理论：全球洋内与陆缘微地块研究的启示（附对该文的审稿意见）     

李三忠  索艳慧  刘博  刘永江  李玺瑶  赵淑娟  朱俊江  王光增  张国伟 《地学前缘》2018,25(5):323-356

任何板块都存在一个由小长大的过程。微地块(微板块)有时是大板块的前身,微地块的起源、生长、夭折、消亡和残留过程对研究板块构造具有重要意义。据其组成,微地块可划分为微陆块、微洋块、微幔块。本文以太平洋、印度洋和大西洋中的微地块为例,系统总结了洋脊增生系统、俯冲消减系统、深海板内系统、伸展裂解系统、碰撞造山系统5种构造环境下的微地块特征,并据此首次进行了成因分类,提出拆离微地块、裂生微地块、转换微地块、延生微地块、跃生微地块、残生微地块、增生微地块、碰生微地块和拆沉微幔块9种类型。对不同类型微地块边界进行了系统界定,并对其成因进行了系统讨论。这些微地块边界类型,包括活动的或死亡的拆离断层、俯冲带、洋中脊、转换断层、破碎带、切割岩石圈的断裂、假断层、洋内汇聚带、叠接扩张中心、非叠接扩张中心、洋脊断错等,其成因的关键研究在于对三节点稳定性进行分析。洋内或洋缘微地块研究,不仅为开展深海大洋精细化构造分析和板块重建工作提供参考,而且对解释大陆内部一些微地块成因具有启发性,可丰富大陆造山带、陆内、板内、幔内和陆缘构造的研究内容,使得造山带演化、板内变形和地幔过程研究更为精细化,甚至推广到早前寒武纪的前板块构造机制研究。  相似文献   

塔克拉玛干沙漠腹地晴天与沙尘暴天气大气边界层对比分析     

张建涛  王敏仲  何清  王延慧  潘红林  张志新 《沙漠与绿洲气象(新疆气象)》2024,18(1):50-58

根据2017、2019年7月塔克拉玛干沙漠腹地GPS探空和地面观测数据,利用位温廓线法等方法,对比分析了沙漠腹地夏季晴天和沙尘暴天气大气边界层结构变化特征。结果表明：晴天和沙尘暴天气大气边界层结构特征显著不同。晴天大气边界层各气象要素垂直分布较为均一,白天对流边界层深厚,高度接近5 km,夜间稳定边界层一般在500 m左右。沙尘暴天气边界层内位温和比湿垂直变化较小,风速较大,可达24.0 m/s,其白天对流边界层在1.5 km左右,夜间稳定边界层在1 km左右。晴天辐射强烈,地表升温迅速,湍流旺盛,是形成晴天深厚对流边界层的主要因素。大尺度天气系统冷平流的动力条件,以及云和沙尘减弱了到达地表的辐射强度是形成沙尘暴天气独特的大气边界层结构的主要因素。  相似文献