Satellite-derived rainfall thresholds for landslide early warning in Bogowonto Catchment,Central Java,Indonesia     

《International Journal of Applied Earth Observation and Geoinformation》2020

Satellite rainfall products for landslide early warning prediction have been spotlighted by several researchers, in the last couple of decades. This study investigates the use of TRMM and ERA-Interim data, for the determination of rainfall thresholds and the prediction of precipitation, respectively, to be used for landslide early warning purposes at the Bogowonto catchment, Central Java, Indonesia. A landslide inventory of 218 landslides for the period of 2003–2016 was compiled, and rainfall data were retrieved for the landslide locations, as given by 6 ground stations, TRMM, and ERA-Interim data. First, rainfall data from the three different sources was compared in terms of correlation and extreme precipitation indices. Second, a procedure for the calculation of rainfall thresholds for landslide occurrence was followed consisting of four steps: i) the TRMM-based rainfall data was reconstructed for selected dates and locations characterized by landslide occurrence and non-occurrence; ii) the antecedent daily rainfall was calculated for 3, 5, 10, 15, 20 and 30 days for the selected dates and locations; iii) two-parameter daily rainfall-antecedent rainfall thresholds were calculated for the aforementioned dates; after analysis of the curves the optimum number of antecedent rainfall days was selected; and (iv) empirical rainfall thresholds for landslide occurrence were determined. The procedure was repeated for the entire landslide dataset, differentiating between forested and built-up areas, and between landslide occurrence in four temporal periods, in relation to the monsoon. The results indicated that TRMM performs well for the detection of very heavy precipitation and can be used to indicate the extreme rainfall events that trigger landslides. On the contrary, as ERA-Interim failed to detect those events, its applicability for LEWS remains limited. The 15-day antecedent rainfall was indicated to mostly affect the landslide occurrence in the area. The rainfall thresholds vary for forested and built-up areas, as well as for the beginning, middle and end of the rainy season.  相似文献   

基于高分遥感影像的建筑物侧面信息提取及其高度计算     

宋旭东  曹文峰  冯德俊  张星星 《北京测绘》2020,(3):296-300

本文选取成都市某一区域建筑物A、B为研究对象,采用分辨率为0.61 m的Quick bird影像,运用图像分割法和LVQ神经网络算法,提取建筑物侧面信息,根据假设法原理,构建高度计算物理模型,求取建筑物高度。对比实测数据,结合可能影响实验结果的实地因素、遥感影像因素进行精度分析与评价,探讨基于高分遥感影像的建筑物侧面信息提取和高度计算的方法。结果表明,LVQ神经网络算法在建筑物侧面提取和高度计算中有更好的应用价值,精度高达94%。  相似文献   

顾及水陆差异的高分五号影像条带去除     

皮原征  储栋  管小彬  沈焕锋 《遥感学报》2020,24(4):360-367

高分五号搭载的可见光短波红外高光谱相机,能获取精细的地物光谱信息,具有十分广泛的应用前景。但高光谱卫星遥感数据往往无法避免条带噪声的干扰,进行条带去除是数据预处理中不可缺少的步骤。传统方法往往对地物的异质性与丰富的细节纹理考虑不足,导致条带不能被彻底地消除。为此,本文提出了一种顾及水陆差异的影像条带去除方法,采用水体与陆地区别统计的策略,解决条带噪声在异质区域的统计特征差异问题,并结合优化统计和一维变分滤波技术实现水陆区域参考统计特征的精确估计,最终基于矩匹配方法分别实现条带去除。实验结果表明:无论是真实实验还是模拟实验,本文提出的算法相较于传统条带去除算法,能更加稳健地去除数据条带噪声,还原地表真实辐射信息;在模拟实验中,本文算法处理结果的峰值信噪比(PSNR)达到46.58,且平均绝对误差(MAE)仅有11.56,均明显优于用于比较的3种传统算法,且算法执行效率也具备优势,能够更好地适用于高分五号大数据量的处理需求。  相似文献   

基于小波变换的射频干扰消除方法的研究          下载免费PDF全文

林天琪  吴亚军  朱人杰  徐志骏 《天文学报》2021,62(3):29

在射电天文观测中,射频干扰(Radio Frequency Interference, RFI)会以多种形式混入望远镜接收系统,给观测带来误判或者降低观测信噪比.近年来国内国际射电天文快速发展,国内国际大型射电望远镜和阵列先后建设,观测灵敏度大为提高,射频干扰的影响尤为突出.随着科技发展和人类活动的加剧,射频干扰日益严重且不可逆转.提出利用2维离散小波变换的方法分析射电天文观测的数据,对望远镜系统输出的时间频率序列进行小波变换,根据小波系数分离出原始信号中各分量,每个分量统计得到相应的阈值,将各分量与阈值相比较识别干扰成分并标记去除.利用该方法对实际观测数据进行了处理,结果表明该方法能够很好地标记并消减干扰信号,且提高了观测的信噪比.  相似文献   

无人机大比例尺测图像控点布设方案设计     

袁德宝  张新新  周振青  任兴达 《北京测绘》2020,(4):523-527

随着无人机技术的快速发展,无人机航空摄影测量的精度也大大改善,以无人机为平台低空摄影测量大比例尺地图成为可能。本文以旋翼无人机搭载非测量型相机,通过布设不同数量像控点进行分析和研究,得到无人机摄影测量在农村地区像控点布设规律。结果证明在合理像控点布设的情况下,无人机测图数字成果空中三角测量、平面和高程精度均可满足1∶500、1∶1000、1∶2000大比例尺地形测图的精度要求。  相似文献   

Satellite image analysis using crowdsourcing data for collaborative mapping: current and opportunities     

Wei Su  Xiaodong Zhang 《International Journal of Digital Earth》2020,13(6):645-660

ABSTRACT

Researchers are continually finding new applications of satellite images because of the growing number of high-resolution images with wide spatial coverage. However, the cost of these images is sometimes high, and their temporal resolution is relatively coarse. Crowdsourcing is an increasingly common source of data that takes advantage of local stakeholder knowledge and that provides a higher frequency of data. The complementarity of these two data sources suggests there is great potential for mutually beneficial integration. Unfortunately, there are still important gaps in crowdsourced satellite image analysis by means of crowdsourcing in areas such as land cover classification and emergency management. In this paper, we summarize recent efforts, and discuss the challenges and prospects of satellite image analysis for geospatial applications using crowdsourcing. Crowdsourcing can be used to improve satellite image analysis and satellite images can be used to organize crowdsourced efforts for collaborative mapping.  相似文献   

一种卫星重力梯度数据的ARMA最优滤波模型构建方法          下载免费PDF全文

朱广彬  常晓涛  付兴科  瞿庆亮 《地球物理学报》2018,61(12):4729-4736

由于卫星重力梯度观测的有色噪声特性和海量观测特征，在利用直接法进行重力场模型的最小二乘求解时，观测值的协方差阵为超大型的非对角阵，这给数值求解带来了极大困难.本文提出了一种基于先验误差功率谱密度的最优ARMA滤波模型构建方法，结合法方程的分块求解策略，可实现对卫星重力梯度观测值的高效滤波处理.数值仿真结果表明，利用最优ARMA滤波器进行时域滤波后，法方程的态性得到了明显改善，重力梯度观测值中的有色噪声得到了有效的"白化"处理，大地水准面精度得到了显著提升.  相似文献   

临汾地震台垂直摆倾斜观测资料阶变异常分析     

张红秀  罗振东  邰垣东  郭国祥 《地震地磁观测与研究》2018,39(4):154-157

对临汾地震台垂直摆倾斜观测资料中记录到的阶变型异常图像进行分析，对异常成因进行探讨，希望对观测数据异常判断、数据预处理及地震预测预报的应用研究，提供一定参考。  相似文献   

Reservoir architecture and heterogeneity distribution in floodplain sandstones: Key features in outcrop,core and wireline logs     

Luis Miguel Yeste  Augusto N. Varela  César Viseras  Neil D. Mcdougall  Fernando García-García 《Sedimentology》2020,67(7):3355-3388

  相似文献   

冻土CT图像中环形伪影和射线束硬化伪影的成因及校正方法     

陈世杰  马巍  李国玉 《冰川冻土》2020,42(4):1407-1416

冻土CT图像中不可避免地会出现环形伪影和射线束硬化伪影。为解决这些问题， 分析了两类伪影的特征和形成机理， 提出了降低伪影的硬件优化方案。首先， 通过改变X射线管电压， 以此改变X射线光通量来降低冻土CT图像的环形伪影。其次， 利用不同厚度的滤过材料， 将X射线中的低能射线预先过滤， 使得穿过冻土试样的X射线能谱范围变窄， 以此来降低射线束硬化伪影对试样的影响。对比分析结果表明： 将扫描电压提高到120 kV既能有效降低同类型冻土试样CT图像中的环形伪影， 又能保证图像的质量； 选用材质为2A12、 厚度为18 mm的航空铝材， 在扫描电压为120 kV、 扫描电流为230 mA的条件下可以有效抑制射线束硬化所造成的伪影。  相似文献