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151.
应用地质地球化学方法对胶东东部昆嵛山复式花岗岩的研究结果表明,该花岗岩体为壳源型花岗岩,是由胶东群、荆山群变质岩系经原地、半原地混合交代作用以及局部重熔作用形成。依据岩体中包体岩石类型的空间组合分带规律,将昆嵛山岩体划分为JDγ型花岗岩和JSγ型花岗岩;并通过研究该两类型花岗岩的岩石化学成份及微量元素特征证明:JDγ型花岗岩的源岩为胶东群,而JSγ型花岗岩的源岩为荆山群。  相似文献   
152.
纹理特征辅助的S AR影像冰川识别   总被引:1,自引:1,他引:0  
范宇宾  郭唯娜  柯长青 《冰川冻土》2019,41(6):1326-1334
青藏高原的冰川监测对气候变化研究有着重要的意义,通过遥感图像可以大范围长时间的监测冰川的变化,识别冰川边界是研究的重点。为了研究SAR影像纹理特征在冰川识别中的作用,以喀喇昆仑山地区的克勒青河上游为研究区,利用2018年Sentinel-1A数据进行干涉处理得到相干系数,然后基于相干系数提取了均值、方差、同质性、反差、相异性、熵、相关性共7种纹理特征,并对不同纹理特征组合之间的提取效果进行了比较。结果表明VV极化方式下均值、方差、同质性、相异性的特征组合冰川识别效果最好。据此提取了克勒青河上游区域的冰川边界,最高精度达到91.36%,该方法明显优于基于相干系数图的阈值分割法和基于光学影像的波段比值法,冰川识别精度提高了约2%。  相似文献   
153.
154.
基于InVEST模型的陕北黄土高原水源涵养功能时空变化   总被引:13,自引:2,他引:11  
以陕北黄土高原为研究区,基于InVEST水源涵养功能评价模块,定量评价退耕还林还草工程背景下土地利用/覆被变化对研究区水源涵养的影响,在此基础上开展水源涵养空间分区。结果表明:① 2000-2010年,陕北黄土高原草地、灌丛和林地的面积分别增加了3204 km2、285.3 km2和122.7 km2,城镇面积增加了450.4 km2;农田、荒漠、湿地的面积分别面积减少了3984.5 km2、72.7 km2和5.2 km2。② 2000-2010年,陕北黄土高原水源涵养量整体以减少为主,中部减少最为显著,减少量在25 m3/hm2~40 m3/hm2,局部区域在40 m3/hm2以上;其他大部分区域均有0~25 m3/hm2不等的减少。③ 陕北黄土高原水源涵养功能高度重要区和极重要区的总面积为32255.1 km2,所占比例为40.5%。④ 通过陕北黄土高原水源涵养功能评价和重要性分区为生态系统的科学管理提供参考。  相似文献   
155.
潞安矿区属黄土丘陵地貌,浅层地震地质条件较好,但由于矿区内村庄、工业矿区等地面建筑较多,严重影响数据采集质量。目前潞安矿区三维地震勘探存在的主要问题为:小构造遗漏较多,特别是5m以下的断层和20m以下的陷落柱;陷落柱的解释误差较大,影响巷道及工作面布置;时深转换不准确,煤层底板等高线出入较大;第四系厚度不准。虽然受测区地震地质条件和技术限制存在多解性和误差,但就潞安矿区已开展的三维地震勘探来看,采区三维地震勘探是潞安矿区精细化地质勘查的必要手段,其在煤矿生产的合理设计、采区的合理划分及巷道、工作面的合理布置等方面发挥了重要作用。  相似文献   
156.
利用WRF(Weather Research and Forecasting)模式,在理想岛屿地形条件下设计了云的微物理冰相过程中水凝物中有霰和无霰的两个对比试验,考察了台风登陆时复杂冰相和简单冰相对台风移动路径、强度和降水增幅的影响。结果表明:1)云微物理过程中有霰的复杂冰相过程时,具有更强烈的云“播撒”效应,因而对台风降水具有明显增幅作用。2)当台风受到理想地形作用时,地形对云“播撒”效应引起的增幅作用具有放大作用,此时台风眼墙非绝热加热量形成明显增强中心,使得台风降水增幅明显。3)当台风登陆时,云微物理冰相过程使得台风越山时存在向西北指向的涡度变化倾向。  相似文献   
157.
The hydrographic and bio-optical properties of the Bering Sea shelf were analyzed based on in-situ measurements obtained during four cruises from 2007 to 2009. According to the temperature and salinity of the seawater, the spring water masses on the Bering Sea shelf were classified as the Alaskan Coast Water, Bering Sea Shelf Water, Anadyr Water, Spring Mixed Layer Water, Remnant Winter Water, and Winter Water, each of which had varying chlorophyll a concentrations. Among them, the highest chlorophyll a concentration occurred in the nutrient-rich Anadyr Water ((7.57±6.16) mg/m3 in spring). The spectrum-dependent diffuse attenuation coefficient (Kd(λ)) of the water column for downwelling irradiance was also calculated, exhibiting a decrease at 412–555 nm and then an increase within the range of 0.17–0.48 m–1 in spring. Furthermore, a strong correlation between the chlorophyll a concentration and the attenuation coefficient was found at visible wavelengths on the Bering Sea shelf. Spatially, the chlorophyll a concentration was higher on the northern shelf ((5.18±3.78) mg/m3) than on the southern shelf ((3.64±2.51) mg/m3), which was consistent with the distribution of the attenuation coefficient. Seasonally, the consumption of nutrients by blooms resulted in minimum chlorophyll a concentration ((0.78±0.51) mg/m3) and attenuation coefficient values in summer. In terms of the vertical structure, both the attenuation coefficient and the chlorophyll a concentration tended to reach maximum values at the same depth, and the depth of the maximum values increased as the surface temperature increased in summer. Moreover, an empirical model was fitted with a power function based on the correlation between the chlorophyll a concentration and the attenuation coefficient at 412–555 nm. In addition, a spectral model was constructed according to the relationship between the attenuation coefficients at 490 nm and at other wavelengths, which provides a method for estimating the bio-optical properties of the Bering Sea shelf.  相似文献   
158.
2018年5月7日厦门岛遭遇了超百年一遇的强降水,对岸滩造成了严重影响。文章采用现场测量、无人机航拍等方法,通过对冲毁岸滩进行现场调查与测量,发现厦门岛东南部10.78km的滨海沙滩岸段,共有10个岸段的沙滩发生明显冲刷,受损岸线总长度为6.1km(占比57%),形成了28条冲刷沟,沙滩遭受的侵蚀面积为20286m2,冲刷量超过4万m3。分析其原因,主要是海岸带开发利用时,不透水面增多且具有一定的坡度,加之后方陆域地下排洪管涵排水,当短期强降水发生时,局部地形集中汇水后急速冲向海岸,导致海岸侵蚀垮塌和后退,沙滩冲刷成沟而流失大量海砂。针对不同沙滩的冲刷程度与影响机制,提出了相应的整治修复方案,可为今后沙滩维护保养提供参考。  相似文献   
159.
Characterization of the hydraulic property of a specific geomaterial is of fundamental importance in engineering design and application. This paper reports an experimental investigation to the hydraulic conductivity of a typical marine sand, i.e., calcareous sand, which becomes increasingly popular as sea-filling material for land reclamation or construction of artificial islands. A series of permeability tests have been performed using the calcareous sand collected from Nansha islands in South China Sea. Using the home-made permeability test apparatus (so-called velocity-controlled pressure-differential acquisition flow apparatus), the relationship between flow velocity and hydraulic gradient was obtained and the hydraulic conductivity of calcareous sand was then determined accordingly. The effects of important parameters, including particle shape and particle size distribution on the hydraulic conductivity of calcareous sand, were assessed. To investigate the effect of particle size distribution on the hydraulic conductivity of calcareous sand, two often-used parameters, i.e., nonuniformity coefficient and curvature coefficient were considered in this study. To quantitatively evaluate the irregularity of soil particle, a particle-shape parameter was introduced and it was able to consider sphericity and circularity of highly irregular particle. Two materials, namely, Fujian quartz sand and glass beads consisting of particles of characteristic shape, were also used in the permeability tests, and they were used to compare with calcareous sand. Through the comparison, the effect of particle shape of calcareous sand on its hydraulic conductivity was examined based on the newly introduced particle shape parameter. The test results indicate that the particle size distribution has a significant influence on the hydraulic conductivity of calcareous sand. The quite irregular particle shape is able to reduce the hydraulic conductivity of the calcareous sand. A comparative study of hydraulic conductivity between the theoretical prediction and experimental measurement was performed, and it is concluded that an improvement of theoretical model for prediction of the hydraulic conductivity of the porous media consisting of particles with highly irregular shapes, such as the calcareous sand, is still required.  相似文献   
160.
辽宁省大气污染对人体健康的危害及研究展望   总被引:10,自引:7,他引:3       下载免费PDF全文
概述了大气污染对人体健康产生的严重危害,分析了辽宁省大气污染特征及居民健康水平的变化趋势,针对大气污染对人体健康影响的研究现状,提出了辽宁省大气污染与人体健康的研究展望。  相似文献   
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