Raman激光雷达探测对流层中上部大气温度分布   总被引：9，自引：0，他引：9       下载免费PDF全文

吴永华  李陶  周军  胡欢陵  岳古明  戚福弟  金传佳 《大气科学》2002,26(5):702-708

介绍了一台氮分子(N2)Raman激光雷达系统.利用N2分子Raman散射和气溶胶及分子的Mie-Rayleigh散射信号,通过同时订正分子、气溶胶和臭氧的衰减,反演出对流层中上部大气密度和温度的垂直分布,其结果与常规球载无线电探空仪探测资料对比,在8～18 km范围内表现了较好的一致性.其中,二者测量的温度在9～15 km高度内相对差别小于4 K.  相似文献   

Physical State and Composition of Polar Stratospheric Clouds Inferred from Airborne Lidar Measurements During SESAME     

C. DAVID  S. GODIN  G. MEGIE  Y. EMERY  C. FLESIA 《Journal of Atmospheric Chemistry》1997,27(1):1-16

The airborne lidar LEANDRE was deployed from Kiruna (Sweden) in January1995, during Phase III of the Second European Stratospheric Arctic andMid-latitude Experiment (SESAME). Polar Stratospheric Clouds (PSC) weredetected on several flights. Four lidar retrievals, on two different days, arepresented together with the thermal history of air masses, derived from 5-daybackward trajectories calculated from the TOPCAT model, using ECMWF analyses.The first PSC case was observed at the synoptic scale and at a temperatureclose to the ice frost point, with no significant depolarization, suggestingthat particles were in the liquid phase, probably liquid ternaryH₂SO₄/HNO₃/H₂Osolution forming a Type 1b cloud. Locally, on the same day, a Type II PSC (icecloud) was detected above the Scandinavian Mountains and was related tomesoscale processes. On another day, the third lidar retrieval only showedbackground aerosols signature, whereas the last one was performed at the NATequilibrium temperature and its measured depolarization ratio was consistentwith few solid state Type Ia particles, probably composed of NAT. From thethermal histories, the different behaviour of the two Type I clouds isexplained in terms of cooling rates and compositional hysteresis, driven bytemperature.  相似文献   

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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