Using an airborne laser scanner for the identification of shallow landslides and susceptibility assessment in an area of ignimbrite overlain by permeable pyroclastics

An airborne laser scanner can identify shallow landslides even when they are only several meters in diameter and are hidden by vegetation, if the vegetation is coniferous or deciduous trees in a season with fewer leaves. We used an airborne laser scanner to survey an area of the 1998 Fukushima disaster, during which more than 1,000 shallow landslides occurred on slopes of vapor-phase crystallized ignimbrite overlain by permeable pyroclastics. We identified landslides that have occurred at the 1998 event and also previous landslides that were hidden by vegetation. The landslide density of slopes steeper than 20° was 117 landslides/km² before the 1998 disaster. This event increased the density by 233 landslides/km² indicating that this area is highly susceptible to shallow landsliding.     

基于二维激光观测的溢油及其乳化过程散射模式研究进展

合成孔径雷达(SAR)以其高分辨率、能不受雨云影响实施全天时全天候全方位监测,在海面溢油灾害应急监测过程中发挥着越来越重要的作用。溢油是因为海面油膜抑制了毛细波和重力波,在SAR图像上呈暗斑而被识别。然而,海面溢油的乳化过程直接影响SAR对海面溢油后向散射截面的观测精度。本研究以物理海洋学和激光原理以及海面电磁散射理论为基础,通过实验利用激光扫描仪观测海面溢油粗糙度,分别与溢油特征参数、后向散射系数建立对应关系;耦合海面溢油参数与后向散射截面的关系,利用电磁散射数值建模方法,建立海面溢油散射模型,研究海面溢油乳化过程对微波后向散射截面的影响。本项目的研究将为SAR监测海面溢油量、溢油厚度及油品分布格局提供了可能;将进一步揭示海面溢油的散射机制,提高SAR海面监测溢油的精度和能力。     

Surveying and modeling of rock discontinuities by terrestrial laser scanning and photogrammetry: Semi-automatic approaches for linear outcrop inspection

Rock face diagnosis is a monitoring operation that is used to optimize rock-risk treatment works in terms of ensuring that safety requirements are met at the lowest cost. Diagnoses require measuring the location and orientation of rock discontinuities at the surface of the rock mass. These measurements are then entered into a structural model that extrapolates the data collected at the surface to the inner part of the rock mass. Currently, most surveys are empirical and are carried out manually using a compass-clinometer. In addition, they tend to examine only the most highly fractured area of a rock face, even though safety considerations demand an exhaustive study of the whole face. These deficiencies can be overcome by using dense 3D measurement techniques such as terrestrial laser scanning and optical imaging to obtain a more complete 3D model and structural statement. Hence, we have developed a semi-automatic process that allows 3D models to be combined with the results of field surveys in order to provide more precise analyses of rock faces, for example, by classifying rock discontinuities into subsets according to their orientation. Further research is being carried out in order to combine 3D data and 2D digital images as a support for structural survey. Trials carried out in a limestone quarry in the French Alps allowed us to compare data sets obtained using manual surveying methods, the well-known laser scanning method and the lower-cost photogrammetric survey method.     

基于多源数据的天山乌鲁木齐河源1号冰川变化研究

基于2012年RTK-GPS、2015年三维激光扫描和2018年无人机航测数据,以天山乌鲁木齐河源1号冰川为研究区,分别从物质平衡、面积、末端等方面分析近期冰川变化.结果表明:乌鲁木齐河源1号冰川近年来呈快速消融趋势.2012—2018年冰川面积减少0.07 km2,年平均面积变化率为-0.01 km2·a-1;同期,...     

天宝TX8三维激光扫描仪在卧式金属罐容积计量中的应用

基于加油站对卧式金属罐容积内部交接的应用需要,本文采用天宝TX8三维激光扫描仪进行容积测量标定,并与传统的容积比较法及激光点阵法对某加油站20 m³卧式金属罐进行数据比较及建模分析。测试数据表明,天宝TX8在卧式金属罐容积标定方面较激光点阵法符合性更高,建模更加全面、直观、高效,为其在其他测量领域及力学建模方面的拓展应用提供了可能。     

基于PR和VIRS融合资料的东亚台风和非台风降水结构分析

借助JAXA/EORC热带台风数据集资料,实现了台风区和非台风区的分离,在此基础上,利用热带测雨卫星搭载的测雨雷达和可见光/红外扫描仪的融合观测资料,对1998~2007年东亚雨季台风及非台风降水的气候特征和降水云红外信号特征进行了分析。结果表明:1)东亚台风降水强度谱较非台风降水谱更宽,特别是对流降水主要分布在5~20 mm/h之间;强降水更多,主要分布在东亚洋面。2)雨季东亚降水的主要形式是非台风层云降水,但台风降水对局地降水量的贡献也不容忽视,例如台湾以东附近洋面可达20%。3)台风降水云亮温海陆分布差异显著;其雨顶高度在4~9 km(层云)和4.5~12.5 km(对流)之间均有分布,较非台风降水雨顶高度谱更宽。4)不同等级的台风在降水强度、覆盖区域和云顶10.8μm亮温分布上差异大。     

无人机及三维激光扫描仪技术在沙滩剖面动态监测中的应用及测量精度分析

沙滩剖面动态监测是沙滩整治修复工程效果评价的基础性工作,同时也是工程实践中及时发现问题并提出解决方案的关键步骤.由于常规测量手段存在工作效率低、周期长、难以全面覆盖测区等局限性,新型技术在沙滩剖面动态监测中的应用研究显得尤为重要.本研究以厦门天泉湾沙滩养护工程为案例,通过无人机航拍技术和三维激光扫描仪获取沙滩数字正射影...     

HY-1卫星水色扫描仪的辐射定标与真实性检验

主要阐述HY－1卫星10波段水色扫描仪辐射定标与真实性检验的基本原理和关键参数的测量方法，简要介绍已开展的工作，并对2类水体测量方法提出几点建议。