宝鸡某场地污染土的分析评价   总被引：5，自引：0，他引：5  

徐永利  王雪莉 《陕西地质》1996,(2)

宝鸡某场地由于长期堆放食盐，造成地基上污染、通过勘察，查明了污染土层，进行了腐蚀性测试和评价，对场地污染区与非污染区土的物理力学性质指标进行了对比，并分析了土的污染机理，提出了防护措施。  相似文献   

Aerosol polarized phase function and single-scattering albedo retrieved from ground-based measurements     

Zhengqiang Li  Philippe Goloub  Claude Devaux  Xingfa Gu  Yanli Qiao  Fengsheng Zhao  Hongbin Chen 《Atmospheric Research》2004,71(4):233-241

Aerosol optical parameters, polarized phase function and single-scattering albdeo, have been retrieved from ground-based sun photometer measurements in Beijing 2003. The measured aerosol optical thickness varies from 0.12 to 0.77 with an average value of 0.39. The measured Ångström coefficient ranges from 0.75 to 1.47 with an average value of 1.21. The retrieved single-scattering albedo at 870 nm is within the 0.76–0.94 range and the average value is 0.85, suggests there are considerable aerosol absorptions in Beijing. The maximum value of retrieved polarized phase function at 870 nm ranges from 0.068 to 0.225 with an average value of 0.16, and it illustrates good correlations with the Ångström coefficient, i.e. the relative size of aerosol particles. Analyses of measurements and theoretical calculations show the polarized phase function is sensitive to aerosol size distribution and complex refractive index, especially the imaginary part of the refractive index which denotes aerosol light absorbing effects. These results suggest that the polarized phase function is an effective and unique aerosol optical parameter and is able to improve the retrieval of aerosol physical properties.  相似文献   

Leaf area index retrieval based on canopy reflectance and vegetation index in eastern China     

JIANG Jianjun  CHEN Suozhong  CAO Shunxian  WU Hongan  ZHANG Li  ZHANG Hailong 《地理学报》2005,15(2):247-254

The aim of this paper is to investigate the feasibility of using Landsat TM data to retrieve leaf area index (LAI). To get a LAI retrieval model based ground reflectance and vegetation index, detailed field data were collected in the study area of eastern China, dominated by bamboo, tea plant and greengage. Plant canopy reflectance of Landsat TM wavelength bands has been inversed using software of 6S. LAI is an important ecological parameter. In this paper, atmospheric corrected Landsat TM imagery was utilized to calculate different vegetation indices (VI), such as simple ratio vegetation index (SR), shortwave infrared modified simple ratio (MSR), and normalized difference vegetation index (NDVI). Data of 53 samples of LAI were measured by LAI-2000 (LI-COR) in the study area. LAI was modeled based on different reflectances of bands and different vegetation indices from Landsat TM and LAI samples data. There are certainly correlations between LAI and the reflectance of Tm3, TM4, TM5 and TM7. The best model through analyzing the results is LAI = 1.2097*MSR + 0.4741 using the method of regression analysis. The result shows that the correlation coefficient R2 is 0.5157, and average accuracy is 85.75%. However, whether the model of this paper is suitable for application in subtropics needs to be verified in the future.  相似文献   

基于长时间序列遥感数据的阿伯德尔国家公园 生态环境质量评价     

王法溧  何晓宇  方泽兴  魏显虎  叶虎平  施令飞 《地球信息科学学报》2019,21(9):1479-1479

阿伯德尔国家公园位于号称肯尼亚“水塔”的阿伯德尔山脉上,是肯尼亚重要的旅游景区和珍稀动植物保护区,开展该地生态环境质量评价对肯尼亚水资源保护与可持续发展具有重要的意义。本研究基于1987-2018年的Landsat系列遥感数据,通过计算综合遥感生态指数RSEI,结合趋势线分析法对阿伯德尔国家公园近32年间生态环境质量变化进行客观定量分析。研究结果显示：① 1987-2018年研究区RSEI均值从0.62下降到0.51,生态环境质量退化的区域面积为551.52 km ²,占总面积的71.85%,表明在气候变化和人类活动影响下,1987-2018年研究区的环境状况呈恶化趋势;②环境质量显著恶化的区域主要分布于亚高山植被区和东部低海拔森林覆盖区,亚高山地区植被生态系统结构单一,稳定性差,对气候变化和人类活动更为敏感;而东部区域存在过度开发,非法砍伐森林等现象,且旅游开发强度大,环境恶化与人类活动密切相关。  相似文献   

The tectono‐metamorphic evolution of the very low‐grade hangingwall constrains two‐stage gneiss dome formation in the Montagne Noire (Southern France)          下载免费PDF全文

M. P. Doublier  S. Potel  K. Wemmer 《Journal of Metamorphic Geology》2015,33(1):71-89

The Montagne Noire in the southernmost French Massif Central is made of an ENE‐elongated gneiss dome flanked by Palaeozoic sedimentary rocks. The tectonic evolution of the gneiss dome has generated controversy for more than half a century. As a result, a multitude of models have been proposed that invoke various tectonic regimes and exhumation mechanisms. Most of these models are based on data from the gneiss dome itself. Here, new constraints on the dome evolution are provided based on a combination of very low‐grade petrology, K–Ar geochronology, field mapping and structural analysis of the Palaeozoic western Mont Peyroux and Faugères units, which constitute part of the southern hangingwall of the dome. It is shown that southward‐directed Variscan nappe‐thrusting (D₁) and a related medium‐P metamorphism (M₁) are only preserved in the area furthest away from the gneiss dome. The regionally dominant pervasive tectono‐metamorphic event D₂/M₂ largely transposes D₁ structures, comprises a higher metamorphic thermal gradient than M₁ (transition low‐P and medium‐P metamorphic facies series) and affected the rocks between c. 309 and 300 Ma, post‐dating D₁/M₁ by more than 20 Ma. D₂‐related fabrics are refolded by D₃, which in its turn, is followed by dextral‐normal shearing along the basal shear zone of both units at c. 297 Ma. In the western Mont Peyroux and Faugères units, D₂/M₂ is largely synchronous with shearing along the southern dome margin between c. 311 and 303 Ma, facilitating the emplacement of the gneiss dome into the upper crust. D₂/M₂ also overlaps in time with granitic magmatism and migmatization in the Zone Axiale between c. 314 and 306 Ma, and a related low‐P/high‐T metamorphism at c. 308 Ma. The shearing that accompanied the exhumation of the dome therefore was synchronous with a peak in temperature expressed by migmatization and intrusion of melts within the dome, and also with the peak of metamorphism in the hangingwall. Both, the intensity of D₂ fabrics and the M₂ metamorphic grade within the hangingwall, decrease away from the gneiss dome, with grades ranging from the anchizone–epizone boundary to the diagenetic zone. The related zonation of the pre‐D₃ metamorphic field gradients paralleled the dome. These observations indicate that D₂/M₂ is controlled by the exhumation of the Zone Axiale, and suggest a coherent kinematic between the different crustal levels at some time during D₂/M₂. Based on integration of these findings with regional geological constraints, a two‐stage exhumation of the gneiss dome is proposed: during a first stage between c. 316 and 300 Ma dome emplacement into the upper crust was controlled by dextral shear zones arranged in a pull‐apart‐like geometry. The second stage from 300 Ma onwards was characterized by northeast to northward extension, with exhumation accommodated by north‐dipping detachments and hangingwall basin formation along the northeastern dome margin.  相似文献   

中国区域MuSyQ叶面积指数产品验证与分析     

马培培  李静  柳钦火  何彬彬  赵静 《遥感学报》2019,23(6):1232-1252

对多源遥感数据协同生产的2010年—2015年中国区域1 km空间分辨率5天合成的MuSyQ（Multi-source data Synergized Quantitative remote sensing production system）叶面积指数LAI产品进行验证。参考现有的LAI产品（MODIS c5，GLASS LAI）和中国生态系统研究网络部分农田和森林站点可用的LAI地面测量数据，从时空连续性、时空一致性、精度和准确性等方面对中国区域的MuSyQ LAI产品进行定性和定量分析与评价。结果表明：（1） MuSyQ LAI产品在保证精度优于MODIS产品的情况下，时间分辨率和时空连续性均有提高。MuSyQ LAI与其他LAI产品（MODIS c5，GLASS LAI）在整体上有很好的一致性（RMSE=1.0，RMSE=0.81），但对常绿阔叶林高值处的描述不稳定；（2） 与LAI地面测量数据相比，MuSyQ LAI产品与地面参考图对比结果较好（最高相关性（R²=0.54）和较低总体误差（RMSE=0.96）），其在阔叶作物生长季高值处有些许低估且在某些阔叶林站点有些高估。整体上，MuSyQ LAI产品呈现出较高的精度，可靠的空间分布和连续稳定的时间分布，且对森林LAI的描述具有更可靠的动态范围。  相似文献   

基于温度植被干旱指数的电网输电线路走廊干旱分析     

孙洋杰  唐华林 《测绘与空间地理信息》2016,(10):94-97

以湖北省输电线路走廊地区作为研究区,利用2013年1~9月MODIS卫星影像数据,处理得到月尺度的归一化植被指数(Normalized Differential Vegetation Index,NDVI)与地表温度(Land Surface Temperature,LST)数据,构建NDVI-Ts特征空间,计算得到温度植被干旱指数(Temperature Vegetation Dryness Index,TVDI),用TVDI监测结果分析湖北省输电线路走廊区域2013年干旱时空分布情况。结果表明,湖北省输电线路走廊地区TVDI和土壤含水量之间存在显著的负相关,相关系数达到0.525(p0.05),由MODIS卫星影像计算得到TVDI影像可以有效表明湖北省输电线路走廊地区的土壤含水情况。  相似文献   

承德初霜冻预报指标分析及其预报方法     

彭九慧  李树丛  陆倩  杨庆红 《沙漠与绿洲气象(新疆气象)》2016,10(3):15-20

应用常规观测资料与ncep1°×1°再分析资料,对承德市各县区初霜的时空分布特征及南北县区初霜出现时间的稳定性进行了分析,在对117个初霜环流形势分析的基础上,建立了初霜预报的天气概念模型;筛选因子,分县区确立了预报指标;采用概率、指标、数值预报产品相结合的方法及概率区间取值法建立了分县区初霜预报模型;检验表明,该模型对于中重度初霜冻预报准确率可达95%以上,对轻度初霜的预报准确率可达68%以上,无漏报出现。  相似文献   

基于Arcgis的地质灾害易发性和危险性分区评价——以宿松县为例     

解会存  金志 《地质灾害与环境保护》2016,(3):86-91

在了解地质环境和灾害特征的基础上,依据综合指数法,确定因子权重,通过Arcgis空间分析软件,作出宿松县斜坡单元网格并进行相应的模拟运算,得出每一个评价单元内所有影响因子的加权和。最后,依据分区标准对易发程度指数图层进行插值处理,便得到宿松县地质灾害的易发性分区。将区域的受威胁对象和易发性叠加计算,将得出各个区域的危险性等级,最后结合地质灾害易发性分区得出危险性分区。分区结果反应出野外调查实际情况。  相似文献   

酉阳河流域典型年汛期的基流分割研究   总被引：2，自引：0，他引：2  

雷宇宽 《水文》2021,41(1):35-41

基流分割是水文学研究中的重难点问题之一,目前基流分割也存在许多方法。基于酉阳河典型年汛期实测日平均流量资料,分别采用Chapman-Maxwell改进方程数字滤波法一次滤波(参数N=1)以及二次滤波(参数N=2)、BFI(f)法、HYSEP固定步长法、HYSEP滑动步长法、HYSEP局部最小值法进行基流分割并对其结果进行分析对比。研究结果表明:不同方法下得到的基流分割线各不相同,各年份基流指数的统计特征也存在一定差异,采用Chapman-Maxwell改进方程数字滤波法二次滤波得到的基流成果更符合基流的一般特征以及酉阳河流域的降水径流关系特点。  相似文献