查询词典 vegetation

Based on AIEM and MIMICS models, the co-relation among radar backscatter, vegetation backscatter and surface backscatter were analyzed, and the linear relation between cross polarization data and vegetation backscatter component was found. Then a simplified vegetation model was constructed after solving the problem of the vegetation backscatter component.

在裸露地表理论模型AIEM和植被散射模型MIMICS模拟分析雷达后向散射与植被散射、地表散射之间相互关系的基础上，分析发现了交叉极化数据与植被体散射量存在的线性关系，从而解决了雷达总后向散射中植被体散射量的问题，进而建立了简化的植被模型。

A three- dimensional turbulence model in non-orthogonal curvilinear coordinates is proposed to investigate the impacts of vegetation on channel morphology. The model includes vegetation-induced drag force and vegetation density in the control equations to describe the effects of vegetation on flow structure, and solves sediment continuity equation to compute channel geometry.

本文建立曲线坐标系下的三维湍流模型研究水生植物对河道形态的影响，在水流控制方程中加入植物阻力项和植物密度项来描述水生植物对水动力特性的贡献，通过泥沙质量守恒方程求解河道变形，在适体网格中求解模型的控制方程。

The water resources change is a leading factor in the vegetation degeneration there; The swamp vegetation was based on the background of large-scale lakes and rivers; the halophyte meadow was based on the background of dry lakes and riverside, and desert vegetation was based on the background of desert; desert vegetation was based on the background of desert at present.

水资源的变化是决定当地植被退化的主导因子，在大面积湖泊、河流背景上是沼泽植被，在干涸湖泊、河床背景上的是盐生草甸植被，在沙质荒漠背景上的是荒漠植被。

As a result of case study in Haidian district, Beijing, the accuracy rate of vegetation fraction estimation by using "dense vegetation model" and "nondense vegetation model" synchronously based on land cove classification is obtained about 75.4%, which is 5.8% higher than that of using "dense vegetation model" only.

根据TM像元为非均一混合像元的特点，提出了基于土地覆盖分类的综合运用"等密度模型"和"非密度模型"计算植被覆盖率的方法，通过对北京市海淀市区的植被覆盖率计算表明，该方法的估算精度可达75.4%，比单纯使用等密度亚像元模型在估算精度上可提高5.8%。

Secondly, According to the sub-pixel structure characteristic, the potential of deriving vegetation fraction from normalized difference vegetation index using the TM data and resorting to "Dense Vegetation Model" and "Nondense Vegetation Model", is studied in an area in the south of Yichang.

本文首先对TM影像进行了几何纠正、辐射校正、大气校正；然后根据混合像元的结构特征，利用TM数据从植被指数中采用"等密度模型"和"非密度模型"提取了宜昌南部地区的植被覆盖度。

Some researchers believe that the latter area possesses savanna vegetation. Savannas are closely associated with seasonal drought, and they may be defined by climatic climax vegetation in tropical and subtropical areas. Based on the ecoclimatic analyses as well as the surviving vegetation in Taiwan, we inferred that the potential natural vegetations of these 2 semi-arid regions were not savanna but forest with some drought-deciduous trees. In conclusion, the physiognomic type of grassland dotted with trees may occur in small areas at present, but Taiwan lacks climate-shaped savanna climax vegetation.

本研究将疏林定义为分布於热带及亚热带之气候形塑的极相植群，气候分析结果表明台湾半乾旱区域之缺水逆境并不严重，再配合现生残存植群之观察，发现台湾有形相为疏林的现生局部性植群，但其潜在自然植群应为参杂有乾旱落叶之阔叶树种的森林，并不存在较大面积之潜在的气候型极相疏林。

The main study areas are as follows: 1 The landscape classification system of the urban-rural ecotone is set up based on the studying on land-use type of urban area and rural area, and then it is used to establish a regional landscape data warehouse for deposition, modification and management; 2 A group of landscape structure and pattern indices and patch area spectrum analysis methods are used to describe the structural and heterogeneous characters of all the landscape elements from different aspects; 3 The temporal and spatial difference of the landscape pattern of main road belts of the research area are also analyzed with the same method. Their basic process and regularity of urban axial expanding of the southwestward of Shanghai City are initially knewn well; 4 According to the traits of the ecotone, the principles and basis of vegetation classification, the ecotone vegetation classification system is set up, its species constitute, community patch characters, the relationship between vegetation types and landscape categories are analyzed, meanwhile, the vegetation sample maps are made; 5 Based on above studies, some landscape ecological stratedies within the research area were discussed. The following are the results of this study

城乡交错带地区的景观分类，在对城市地区和农村地区的土地利用类型研究的基础上建立了城乡交错带的分类体系，并在此基础上用ARC＼INFO软件分时段、分区、分要素建立研究区的景观图形数据库，对数据进行存储、修改和管理；2）利用多种景观结构、格局指数和斑块面积谱分析方法，从不同的侧面对各种景观组分的结构以及区域的景观格局特征进行了分析，并对其成因进行了探讨；3）利用相同的分析方法，分析了城乡交错带中的城市干道两侧的景观格局特征的空间和时间分异情况，初步掌握上海城市西南轴向扩张的基本过程和规律；4）对城乡交错带中非独立的景观要素-植被，研究其遥感图象信息的基本特征，建立适合区域特点的植被分类体系，并在样区中建立了植被图形数据库和计算机制图，分析了植被景观种类组成、斑块等级等特征以及与不同景观的相互关系；5）在上述研究的基础上，对研究区内的景观生态对策进行了研究。

Based on the meteorological observation data and the vegetation index data in Yulin,synchronousness relationship of vegetation index and sandstorm activities were analyzed,the results indicates that,Intra-annual changes of vegetation covers and sandstorm activities are evidently inverse synchronous,which may conduce to reducing the wind-break and sand-fixing function of vegetation.

以榆林市为例，利用气象观测和植被指数数据，对植被覆盖与沙尘暴活动发生的时间同步性关系进行了分析，结果显示：植被覆盖与沙尘暴活动存在着年内的时间不同步性，严重制约植被防风固沙生态功能的发挥；沙尘暴日数与植被指数的年际变化呈现出反相关系证明了植被覆盖对沙尘暴活动具有很强的防护作用。

The following results are made from this research: Assessing data quality and band combination of different bands in line with geo-target features in desertification areas, and determining basic bands for desertification monitoring. And understanding and studying the spectral features and variation rules of geo-targets in the experimental area, raising that it is the basis of geo-targets information collection with imaging spectrometer data to understand spectral features and variation rules of geo-targets, realizing that in a great extent spectral-integrated-form-based classification method can remove the phenomenon of "different spectrum with same objects" resulted from reflection ratio curve translation because of the angle change among sensor, targets and observation direction, and the average and variance images can be introduced to solve the problem of two kinds of geo-target with similar spectral forms and much different values of whole reflectionratio. It is suggested that "red edge" range bands of vegetation, which has close relationship with vegetation cover and biomass, is the main characteristic bands and important basis for careful vegetation classification and quantitative retrieval, and pixel-based derivative spectral analysis is very useful for removing the effects of soil background values and quantitatively retrieving vegetation biomass and cover. The remote sense quantitative retrieval model is developed for main appraisable factors of desertification monitoring assessment with imaging spectrometer data and then the applicability of model is analyzed.

研究结果如下：首先针对荒漠化地区的地物特征，对高光谱数据不同波段的数据质量、波段组合进行了评价，提出了适用于荒漠化监测的基本波段选择集；初步了解和掌握了研究地区的地物光谱特性及变异规律，进一步明确了掌握地物光谱特征和变异规律是用成像光谱仪数据提取地物信息的基础；发现了基于光谱整体形状的分类方法在很大程度上能够消除由于传感器、地物目标观测方向之间的角度变化引起的反射率曲线整体平移的"同物异谱"现象，对于谱形相似而整体反射率的值相差较大的两类地物，通过引入均值和方差图像参与分类得到解决；研究还表明在植被"红边"范围内的波段是进行荒漠化监测的主要特征波段，这些波段与植被生物量和盖度都有密切的关系，是开展精细植被分类研究和植被定量反演的重要基础；像元的导数光谱分析可以消除土壤背景的影响，是进行植被生物量和盖度定量反演的有力工具；建立了荒漠化监测主要评价因子的定量反演模型，并分析了模型的适用性。

The following results are made from this research: Assessing data quality and band combination of different bands in line with geo-target features in desertification areas, and determining basic bands for desertification monitoring. And understanding and studying the spectral features and variation rules of geo-targets in the experimental area, raising that it is the basis of geo-targets information collection with imaging spectrometer data to understand spectral features and variation rules of geo-targets, realizing that in a great extent spectral-integrated-form-based classification method can remove the phenomenon of "different spectrum with same objects" resulted from reflection ratio curve translation because of the angle change among sensor, targets and observation direction, and the average and variance images can be introduced to solve the problem of two kinds of geo-target with similar spectral forms and much different values of whole reflectionratio. It is suggested that "red edge" range bands of vegetation, which has close relationship with vegetation cover and biomass, is the main characteristic bands and important basis for careful vegetation classification and quantitative retrieval, and pixel-based derivative spectral analysis is very useful for removing the effects of soil background values and quantitatively retrieving vegetation biomass and cover. The remote sense quantitative retrieval model is developed for main appraisable factors of desertification monitoring assessment with imaging spectrometer data and then the applicability of model is analyzed.

研究结果如下：首先针对荒漠化地区的地物特征，对高光谱数据不同波段的数据质量、波段组合进行了评价，提出了适用于荒漠化监测的基本波段选择集；初步了解和掌握了研究地区的地物光谱特性及变异规律，进一步明确了掌握地物光谱特征和变异规律是用成像光谱仪数据提取地物信息的基础；发现了基于光谱整体形状的分类方法在很大程度上能够消除由于传感器、地物目标观测方向之间的角度变化引起的反射率曲线整体平移的&同物异谱&现象，对于谱形相似而整体反射率的值相差较大的两类地物，通过引入均值和方差图像参与分类得到解决；研究还表明在植被&红边&范围内的波段是进行荒漠化监测的主要特征波段，这些波段与植被生物量和盖度都有密切的关系，是开展精细植被分类研究和植被定量反演的重要基础；像元的导数光谱分析可以消除土壤背景的影响，是进行植被生物量和盖度定量反演的有力工具；建立了荒漠化监测主要评价因子的定量反演模型，并分析了模型的适用性。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐