轻型机载LiDAR在农村宅基地房屋测量中的应用

选择新疆焉耆县北大渠乡北大渠村房屋密集区作为研究区,通过三角翼搭载轻型机载LiDAR进行了低空（170m）交叉航线高密度点云数据采集,对点云数据进行拼接、校正、纹理信息增强,在点云上对房屋进行矢量化,并对结果进行精度检查。点云数据房角点采集率为83.3%,中误差为4.8cm。采用机载LiDAR测量房角点能够大大减少外业房角点测量的工作量。机载LiDAR的应用鲜有纹理信息的提取,本次测试通过对高密度点云数据进行有效的处理,提取了点云数据纹理信息,为机载LiDAR数据纹理信息的应用提供了参考,并对其精度有了明确的认识,可为后期相关工作的开展提供借鉴。     

中国陆地背景和土壤光谱反射特性的地理分区的初步研究

通过对土壤光谱反射特性与土壤理化性状关系的研究,并根据我国土壤的分布规律,提出了以植被覆盖度和土壤光谱反射特性为基础的我国陆地背景地理分区的初步方案。该方案把我国划分为6个区和23个亚区。     

土壤激光诱导荧光遥感研究初探

对我国不同土壤的激光诱导荧光光谱的研究表明,在可见光波段的荧光峰一般在450nm左右,其相对荧光强度与土壤有机质含量、粘粒含量、水分含量以及土壤的化学组成密切相关。还表明.测试环境的差异,并不改变土壤的荧光光谱特征,仅影响它的相对荧光强度;不同的植被覆盖度会明显引起土壤荧光光谱的相应变化。这些结果展示出了激光荧光遥感技术应用于土壤类型和某些性状探测的可能性。应用红光波段是识别植被和土壤的最佳荧光波段。     

不同养分供应状况对水稻荧光光谱特征的影响及其在遥感应用上的意义

在不同的养分供应状况下,对水稻在几个生育期的荧光光谱特征的研究表明:氮素供应的减少会引起水稻叶片荧光光谱中蓝绿波段峰的强度在有效分蘖期时降低,无效分蘖期始升高,并使红波段峰的强度和特征峰之间的强度比值(如440nm/550nm)在各生育期均有所降低;利用水稻叶片荧光光谱特征的变化监测其养分供应状况是可能的;监测波段以400—800nm为宜,监测时期应为分蘖盛期一孕穗期。     

An Integrated Multi-Level Early Warning Method for Rainfall-Induced Shallow Landslides

Rainfall-induced landslides have occurred frequently in Southwestern China since the Wenchuan earthquake,resulting in massive loss of people''s life and property. Fortunately,landslide early-warning is one of the most important tools for landslide hazard prevention and mitigation. However, the accumulation of historical data of the landslides induced by rainfall is limited in many remote mountain areas and the stability of the slope is easily affected by human engineering activities and environmental changes, leading to difficulties to accurately realize early warning of landslide hazards by statistical methods. The proposed warning method is divided into rainfall warning component and deformation warning component because the deformation induced by rainfall has the characteristic of hysteretic nature. Rainfall, tilted angle and crack width are chosen as monitoring indexes. Rainfall grade level that contains rainfall intensity and duration information is graded according to the variation of the safety factor calculated by 3-D finite difference numerical simulation method, and then is applied using the strength reduction method and unascertained information theory to obtain the deformation grade level of several monitored points. Finally, based on the system reliability theory, we establish a comprehensive landslide warning level method that provides four early warning levels to reflect the safety factor reductions during and post rainfall events. The application of this method at a landslide site yield generally satisfactory results and provide a new method for performing multi-index and multi-level landslide early warnings.     

模拟酸雨对水稻叶片反射光谱特性影响的初步研究

本文研究了模拟酸雨对水稻叶片反射光谱特性的影响。结果表明：模拟酸雨会引起水稻叶片反射光谱的可见光区和中红外区的反射率升高，近红外区的反射率降低，相应的反射率比值也随之变化，一阶和二阶微分光谱蓝移，且上述变化的程度与酸雨的酸度、水稻的品种和生育期有关。这一结果也表明遥感技术监测酸雨污染作物是可行的。     

Estimation of Lightning-Generated NOx in the Mainland of China Based on Cloud-to-Ground Lightning Location Data

Lightning-generated nitrogen oxides(LNO_x) have a major influence on the atmosphere and global climate change.Therefore, it is of great importance to obtain a more accurate estimation of LNO_x. The aim of this study is to provide a reference for the accurate estimation of the total LNO_x in the mainland of China based on cloud-to-ground lightning(CG)location data from 2014 to 2018. The energy of each CG flash was based on the number of return strokes per CG flash, t...     

福建省古田试验区云系回波特征与人工增雨作业条件分析

利用2008—2012年4—6月古田试验区的新一代天气雷达、探空及地面雨量观测等资料,结合天气形势分析,研究古田试验区云系的回波特征与人工增雨作业条件,结果表明:影响古田试验区的主要天气系统分别为低涡切变、暖区辐合、高空槽和大陆高压。降水云系以积层混合云为主,其次为积状云。天气系统所对应的云系回波类型及降水情况有明显差异,积层混合云的结构有利降水;积层混合云大于25 d Bz的回波面积明显比积状云大,且平均回波顶高和最大回波顶高均比积状云低;积状云的垂直积分液态水含量明显比积层混合云大;积状云和积层混合云的负温层厚度超2 km;积层混合云的最大回波强度、大于25 d Bz的回波面积和负温层厚度与区域平均日雨量有着明显的对应关系。古田试验区积层混合云的作业指标为回波强度大于25 d Bz,大于25d Bz的回波面积S25 d Bz要大于400 km~2,回波顶高大于5.5 km,负温层厚度大于1.5km,垂直积分液态水含量大于1 kg/m~2。     

村庄地籍调查中轮台1∶1000真正射影像生产及其应用评估

以轮台县境内具有村庄地籍调查代表性的哈尔巴格乡喀什贝西村和吾夏克铁热克村为研究区,基于数字表面模型(DSM),完成真正射纠正,生成真正射影像(TDOM)。生成的真正射影像平面精度可达到0.1 m,优于1∶1000数字线划图点位中误差(0.4 m)的要求;TDOM能够克服遮挡和倾斜问题,建立完全垂直视角的地表景观,使建筑物保持垂直视角,避免房屋对其他地表信息的遮挡,恢复地物的正确方位;将TDOM作为村庄地籍调查的工作底图,直接对其进行地物矢量化,可快速准确地完成数字线划图(DLG)的绘制,省去立体测图的过程,大大降低制图成本,提高工作效率,在村庄地籍调查中具有较高的应用价值。     

库布齐沙漠南缘抛物线形沙丘表面风沙流结构变异

对库布齐沙漠南缘抛物线形沙丘表面气流和输沙率的野外观测和分析结果表明,沙丘表面约90%的风沙输移集中在距沙面0.10 m高度范围内,输沙率随高度递减的形式在沙丘各部位因风速、下垫面状况和坡面形态不同而发生变异。沙丘迎风坡坡脚因出露坚硬、含砾石地表,颗粒跃移高度大,风沙流上层相对输沙率大;迎风坡沙粒沿坡向上运动,颗粒跃移高度减小,风沙流中近地表相对输沙率大;沙丘背风坡沙粒沿坡向下运动,加之来自丘顶变型跃移物质的影响,风沙流上层相对输沙率较大;脊线受迎风坡各个断面地形差异的影响,各观测点间风沙流结构差异显著。风沙流结构在迎风坡和丘顶均遵循指数递减规律(Q=aexp(-z/b)),其中,指数函数拟合中系数a与输沙率具有良好的幂函数关系,随风速增加而增加,但二者关系较弱;b与二者无相关性。背风坡风沙流结构具有明显的分段现象,以0.10 m高度为界,下层符合指数函数,上层符合幂函数。