SURF算法在无人机倾斜摄影测量三维建模中的应用

针对无人机倾斜摄影测量影像的特点,采用一种影像特征点自动提取匹配算法,解决影像之间的比例尺不一致、分辨率不一致等问题,实现影像的自动精确匹配,最终构建具有精确地理信息的三维模型。实验结果表明构建的三维模型满足数字城市建设的需求,可为城市基础设施建设提供一种科学可靠的依据。     

基于电子水准仪的矿区独立高程系统优化设计

矿区多采用独立高程系统,是建立时间早、长周期运行的水准控制网,期间会经历水准点严重沉降、破坏、新测量技术发展和新应用需求等的影响,需要优化设计。某矿严格按照二等水准测量规范,结合矿区及周边实际情况和道路设施变迁等,合理设计水准路线,利用高精度的SDL1X型水准仪施测,优化升级高程控制网。按照间接平差原理解算所得最弱点精度较高,全网在精度、稳定性和可靠性方面均有提升。分析可得,该优化方案切实有效。     

PLANETARY BOUNDARY LAYER HEIGHT MEASURED BY A WIND PROFILER BASED ON THE WAVELET TRANSFORM

Planetary boundary layer height (PBLH) is an important input parameter for any boundary layer study or model, either climate or atmospheric. The variation of the PBLH is also of great significance to the physical processes of numerical prediction, diagnosis of weather forecasting and monitoring urban pollutants. However, effective ways to monitor the PBLH continuously are lack. Wind profilers are commonly used in monitoring PBLH continuously because of its high temporal and spatial resolution, coupled with capability of continuous detection. In this paper, the covariance wavelet transform (CWT) is used to analyze the range-corrected signal-to-noise ratio (SNR) of the wind profiler to determine the PBLH, which is then compared with the results measured by the gradient method and the radiosonde. The conclusions are as follows: (1) The scaling parameter a and translation parameter b of the wavelet are critical in determination of the PBLH by applying the CWT as different values may get completely different results, which requires to select appropriate values in the calculation carefully. (2) Quality control is crucial in determining the PBLH because good quality control can help remove mutation points, which makes the determined PBLH more consistent with the actual situation. (3) In clear-air, the gradient method is not applicable if the boundary layer turbulence is inhomogeneous and the impact of noise is large for that it is easy to be impacted by the mutation of SNR caused by the atmosphere turbulence instability and other factors, which will cause large errors, while the CWT method as an improvement of the gradient method can determine the PBLH quite well. (4) Through quality control, the PBLHs determined by the CWT are consistent with those of radiosonde, and the correlation coefficient between them is 0.87.     

兰州市城市热岛效应与地表指数定量分析

针对现有兰州市城市热岛效应研究多以地面气象站的观测资料为数据源,以遥感影像为数据源较少的现状,该文利用Landsat 8影像,研究了兰州市城市热岛效应与修改后的土壤调节植被指数(MSAVI)、增强型水体指数(EWI)、土壤亮度指数(NDSI)、土壤湿度指数(NDMI)之间的关系。结果表明,兰州城市热岛效应较为严重,城市热岛效应与土壤湿度指数、增强型水体指数、土壤亮度指数呈正相关,与修改后的土壤调节植被指数呈负相关。     

数值模式对强台风“菲特”登陆期间预报能力评述

基于自动站观测和ECMWF再分析资料,针对中国气象局上海台风研究所区域高分辨率台风模式(Shanghai Tropical Cyclone High Resolution Analysis and Prediction System,STI-THRAPS)和业务常用的4个数值模式,即欧洲中期天气预报中心(European Centre for Medium-range Weather Forecasts,EC)全球模式,美国全球预报系统(The Global Forecast System,GFS),日本气象厅(Japan Meteorological Agency,JMA)全球模式和我国T639(T639L60)全球模式,对1323号台风"菲特"登陆过程的预报性能进行了综合检验评估。结果显示:对暴雨以上的强降水预报STI-THRAPS有明显优势。仅有该模式对超过500 mm的极端降水做出预报,且各项评分均好于全球模式,漏报率也明显优于其他模式。对暴雨以下的降水预报各个模式差距不大。美国GFS和STI-THRAPS较好地预报了大风区,STI-THRAPS预报的风场与实况的空间相关程度最高。从漏报率上来看,STI-THRAPS模式的风场预报具有明显优势。虽然预报最大风速偏大,但是STI-THRAPS在24 h后的路径预报有较大优势。     

山东省农村居民点转型的空间特征及其经济梯度分异

为探究农村居民点转型的空间结构及其与经济发展的关联性,以山东省为例,基于农村宅基地转型的理论假设与测度方法,运用空间关联分析方法研究农村居民点转型的空间布局和集聚特征,并以人均GDP作为特征指标划分各县级行政区的经济发展梯度,从省级全域层面和“点、线、面”特征单元综合的角度,揭示农村居民点转型与经济发展的相关性及其耦合关系。结果显示,在空间分布上,2005-2014年山东省农村居民点转型指数呈现西高东低和南高北低的态势;在全局趋势上,Moran's I指数达到0.6317,说明农村居民点转型存在显著的空间集聚现象;在局部趋势上,农村居民点转型的热点区和次热点区集中分布在鲁西黄泛平原、鲁西南淮河平原以及鲁中沂蒙山区,次冷点区分布在次热点区外围,冷点区分布在胶东丘陵地区和鲁北黄河三角洲地带;在相关性分析上,农村居民点转型与经济发展水平具有明显的数理统计相关性和空间耦合性,无论是全域层面还是特征单元,农村居民点转型均表现出从低级到高级经济梯度的递减规律、且乘幂变化趋势显著。本文探索了农村居民点转型的空间特征,弥补了土地利用转型空间性分析的不足;同时研究结果也较好地验证了前人提出的理论假设。     

民族文化资源的类型特征及成因分析——以格萨尔（果洛）文化生态保护实验区为例

由人类非物质文化遗产《格萨（斯）尔》史诗派生出的格萨尔文化是青藏高原地区独特的区域文化形态。文化资源是文化的载体和展示形式,具有价值性和不可替代性。研究格萨尔文化资源的分类、空间分布及成因对于探讨青藏高原地区人地关系,保护人类非物质遗产有非常重要的意义。果洛藏族自治州是格萨尔文化资源最为富集的区域,并于2014年被授予格萨尔文化生态保护实验区。本文首先对格萨尔文化资源进行界定和分类,并以果洛为例,探讨格萨尔文化资源的空间分布特征及与自然地理条件（高程、水源、坡度、坡向、可达性）的关系,并分析影响文化资源分布的原因,得出以下结论：① 格萨尔文化资源可以分为4大类,11个亚类和60个子类,果洛的格萨尔文化资源覆盖全部类型,共1189个;② 果洛格萨尔文化资源空间分布具有聚集性,其中A类文化人（团体）类集聚程度最高,并通过最近邻分析和密度分析对各类文化资源的集聚空间进行识别;③ 格萨尔文化资源的空间分布与自然地理条件有关,多位于海拔相对较低、距水源地较近的位置,不同类型的文化资源分布对坡度、坡向和可达性的关系不同。     

云南省食用菌产业物流网络研究

构建合理高效的农产品物流网络,是实现农产品流通与增值并促进区域农业发展的重要基础。为构建云南省食用菌物流网络,分析了2004—2015年食用菌产业数据,揭示了食用菌产业的分散化、边缘化、不均衡的空间分布特征。从资源状况、社会经济、交通区位3个方面提出了物流节点等级的评价指标体系。依据货运联系强度模型确定轴心城市辐射范围,构建了以昆明市、曲靖市、楚雄州为中心城市圈,辐射带动滇东北、滇南的滇中食用菌物流圈和以大理州为物流核心、辐射带动滇西北地区的滇西食用菌物流圈。并以此形成云南省食用菌轴辐式物流网络。     

Analysis of the Spatio-temporal Changes in Acid Rain and Their Causes in China (1998-2018)

With the rapid development of the economy, acid rain has become one of the major environmental problems that endanger human health. Being the largest developing country, the environmental problems caused by acid rain are of increasing concern with the rapid industrialization and urbanization in China. Recently, many researchers have focused on acid rain. To better understand the temporal and spatial dynamics of acid rain in China, the monitoring data on acid rain from 1998 to 2018 were studied using ArcGIS 10.2. The results show that the proportion of acid rain cities, the frequency, and the area of acid rain were decreasing, however, the situation still remains serious. Overall, the chemical type of acid rain was mainly sulfuric acid rain. However, the concentration ratio of SO₄ ^2-/NO₃ ^- decreased by 81.90% in 2018 compared with 1998, and presented a decreasing trend, which indicates that the contribution of nitrate to precipitation acidity has been increasing year by year. This research will help us to understand the distribution characteristics and causes of acid rain in China, and it may provide an effective reference for the prevention and control of acid rain in China.     

Effects of Enclosure on Plant and Soil Restoration in the Junggar Desert

Enclosure is commonly used in the restoration of degraded grasslands. However, the effects of enclosure on grassland plant and soil restoration remain controversial, particularly in deserts. To assess the effects of enclosure on desert plants and soil properties, using high throughput sequencing, the differences between plants and soil were systematically analyzed before and after enclosure construction. The soil organic carbon, total nitrogen and total phosphorus contents of the three desert flora increased and decreased, but the difference was not significant; enclosure increased plant height, coverage, aboveground biomass, and species richness by 58.99%, 59.35%, 33.29%, and 51.21%, respectively, in a Seriphidium transiliense formation; by 15.49%, 33.52%, 20.85%, and 5.13%, respectively, in a Haloxylon persicum formation; and by 83.80%, 31.51%, 76.66% and 33.33%, respectively, in an Anabasis salsa formation. For soil bacteria, enclosure significantly increased the average number of operational taxonomic units and Shannon-Wiener index by 12.74% and 2.92%, respectively, under S. transiliense formation and by 17.08% and 3.17%, respectively, under H. persicum formation. However, enclosure had no significant effect on the average number of operational taxonomic units or Shannon-Wiener index under A. salsa formation. Enclosure significantly increased desert plants, soil bacterial diversity, and desert plant community productivity; however, the increase in soil nutrient content was not significant. These results demonstrate that enclosure is effective for restoring desert ecosystems but may have little effect on the soil nutrient content.