Extracting photogrammetric ground control from lidar DEMs for change detection   总被引：2，自引：0，他引：2  

Timothy D.  James  Tavi  Murray  Nicholas E.  Barrand  Stuart L.  Barr 《The Photogrammetric Record》2006,21(116):312-328

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Cloud-base distribution and cirrus properties based on micropulse lidar measurements at a site in southeastern China     

Jianjun Liu  Zhanqing Li  Youfei Zheng  Maureen Cribb 《大气科学进展》2015,32(7):991-1004

The cloud fraction(CF) and cloud-base heights(CBHs), and cirrus properties, over a site in southeastern China from June 2008 to May 2009, are examined by a ground-based lidar. Results show that clouds occupied the sky 41% of the time.Significant seasonal variations in CF were found with a maximum/minimum during winter/summer and similar magnitudes of CF in spring and autumn. A distinct diurnal cycle in the overall mean CF was seen. Total, daytime, and nighttime annual mean CBHs were 3.05 ± 2.73 km, 2.46 ± 2.08 km, and 3.51 ± 3.07 km, respectively. The lowest/highest CBH occurred around noon/midnight. Cirrus clouds were present ～36.2% of the time at night with the percentage increased in summer and decreased in spring. Annual mean values for cirrus geometrical properties were 8.89 ± 1.65 km, 9.80 ± 1.70 km, 10.73 ± 1.86 km and 1.83 ± 0.91 km for the base, mid-cloud, top height, and the thickness, respectively. Seasonal variations in cirrus geometrical properties show a maximum/minimum in summer/winter for all cirrus geometrical parameters. The mean cirrus lidar ratio for all cirrus cases in our study was ～ 25 ± 17 sr, with a smooth seasonal trend. The cirrus optical depth ranged from 0.001 to 2.475, with a mean of 0.34 ± 0.33. Sub-visual, thin, and dense cirrus were observed in ～12%, 43%, and 45%of the cases, respectively. More frequent, thicker cirrus clouds occurred in summer than in any other season. The properties of cirrus cloud over the site are compared with other lidar-based retrievals of midlatitude cirrus cloud properties.  相似文献   

Preparing The National Map for the 3D Elevation Program – products,process and research     

S.T. Arundel  L.A. Phillips  A.J. Lowe  J. Bobinmyer  K.S. Mantey  C.A. Dunn 《制图学和地理信息科学》2015,42(4):40-53

The 3D Elevation Program (3DEP) is a collaborative effort among government entities, academia, and the private sector to collect high-resolution 3-dimensional data over the United States. The United States Geological Survey (USGS) is making preparations for managing, processing, and delivering petabytes of 3DEP elevation products for the Nation. In addition to the existing 1/3, 1, and 2 arc-second seamless elevation data layers of The National Map, new 3DEP products include lidar point cloud data; a standard 1-meter DEM layer; additional source datasets; and, in Alaska, 5-meter digital elevation models. A new product generation system improves the construction and publication of the seamless elevation datasets, prepares the additional 3DEP products for distribution, and automates the data management functions required to accommodate the high-volume 3DEP data collection. Major changes in geospatial data acquisition, such as high resolution lidar data, volunteered geographic information, data processing using parallel and grid computer systems, and user needs for semantic access to geospatial data and products, are driving USGS research associated with the 3DEP. To address the research requirements, a set of inter-related projects including spatiotemporal data models, data integration, geospatial semantics and ontology, high performance computing, multi-scale representation, and hydrological modeling using lidar and other 3DEP data has been developed.  相似文献   

A comparison of lidar and echosounder measurements of fish schools in the Gulf of Mexico     

Churnside  James H.; Demer  David A.; Mahmoudi  Behzad 《ICES Journal of Marine Science》2003,60(1):147-154

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固体激光测风雷达扫描镜旋转控制系统     

张博  刘智深  张凯临  黄海龙 《中国海洋大学学报(自然科学版)》2003,33(4):621-626

多普勒激光测风雷达是近年来方兴未艾的 1种全新的大气风场探测手段。但是激光测风雷达直接测量的是视线方向上的激光反射光的频移 (视线风速 )。在这个基础上 ,激光雷达还必须能够获得多方位的风速数据才能够反演出风场。这就需要相应的光学扫描系统 ,它在保证发射、接收视场重叠的前提下 ,控制激光束投射到指定的方向 ,使激光雷达获得不同视线角度的风速数据。本文介绍的激光雷达测风系统中的光学扫描部分实现了上述要求 ,在水平旋转和俯仰控制上的精度都达到了<0 .5°。完全能够满足激光测风系统的实用需要。  相似文献   

机载海洋激光荧光雷达测量海表层叶绿素a浓度的算法研究     

魏志强  张凯临  吴东 《中国海洋大学学报(自然科学版)》2007,37(1):157-162

基于中国海洋大学研制的我国首台机载海洋激光荧光雷达系统及其测量海水中叶绿素a浓度的方法;对该系统在烟台至荣成沿岸海域进行实验的情况作一回顾,并对实验数据进行了处理,采用拉曼校正归一方法,反演了海表层的叶绿素a浓度,同时利用激光雷达方程反演出了海水的衰减系数;另外,提出了最小二乘拟合提取信号峰值的新反演算法。反演结果与往年同时期采集数据较为吻合,使用最小二乘拟合提取信号峰值的算法反演的叶绿素a浓度更接近于近期实地测得的结果。  相似文献   

基于小波分层原理的机载激光雷达数据滤波     

王刃  徐青  朱新慧 《海洋测绘》2007,27(6):52-54

分析了小波变换的基本原理并把小波变换引入到了机载激光雷达数据滤波中,实现了DSM数据的快速、高精度的滤波。在文章的最后,利用英国Birmingham地区的实验数据对基于小波分层原理的数据滤波方法进行了验证,结果表明基于小波分层原理的数据滤波方法的正确率优于94%,精度优于±0.71m。  相似文献   

Photogrammetric and lidar data integration using the centroid of a rectangular roof as a control point     

Edson  Mitishita  Ayman  Habib  Jorge  Centeno  Alvaro  Machado  Jennifer  Lay  Carmen  Wong 《The Photogrammetric Record》2008,23(121):19-35

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激光雷达数据质量控制研究     

朱毅  许波  费松  孙新会 《气象科学》2018,38(5):692-698

气溶胶激光雷达是大气气溶胶探测的有效技术手段,是对常规地面监测技术有力的支撑和补充,数据质量控制是业务推广与深入研究的根本保障。为构建激光雷达业务观测网,必须深入探讨气溶胶激光雷达的数据质量控制方法。本文从气溶胶激光雷达基本原理出发,分别针对数据质量控制的核心指标距离精度标校、通道增益比、单脉冲能量、几何重叠因子、背景基线、数据反演方法进行了详细讨论,为建立米散射气溶胶激光雷达的数据质控方法提供了有效参考依据。  相似文献   

华北香河站一次霾污染事件的综合观测研究     

夏俊荣  吴丹  齐冰 《气象与环境科学》2016,39(2):10-17

利用激光雷达、太阳光度计、系留气艇低空探测数据及MODIS卫星数据等多源资料,对2007年2月初发生在我国中东部地区的一次大范围霾污染事件进行了综合分析,重点分析了华北香河站垂直向气溶胶光学特性的变化特征,并初步讨论了气溶胶区域输送。分析结果表明:霾污染中心位于大城市、城市群或者盆地等污染物源排放强度大或者地形不利于污染物扩散的地区,形成了6个污染中心;2日霾最严重时,近地面气溶胶消光系数(355nm)达到1.8 km~(-1),是霾发生前的3倍;霾最严重时气溶胶光学厚度(340 nm)为1.4,较前后日的高;随着边界层高度的下降,底层气溶胶快速积累;香河站气溶胶在垂直向存在明显的分层现象,上层600—1000 m高度气溶胶受区域输送的影响,其光学厚度占整层气溶胶的比值能达到43.6%,甚至更高;本次霾过程以细粒子为主;弱高压系统、低至100 m左右的逆温层高度及低风速等气象条件对此次霾的形成起到了重要的作用;而3日出现的大风则很可能是驱散霾的重要因子。  相似文献