地图数据缩编更新中的道路自动选取研究

总结道路选取的研究现状,分析在道路的缩编更新过程中,道路要素选取需要考虑的要素指标.介绍一种道路选取方法,综合考虑道路的等级、长度、网眼面积、区域道路密度、是否是悬挂链等几何、语义和拓扑信息,模拟人类在缩编更新时的思维过程,实现道路的自动选取,并进行试验,验证方法的有效性.     

基于KML的三维专题图表示方法

近几年来,虚拟地理环境系统得到广泛应用.专题图制作在制图学上有着悠久的历史.但是在虚拟地理环境浏览系统中(如Google Earth)对专题要素的表达没有得到足够的重视.文中研究如何利用KML制作专题符号,并在三维虚拟地理环境浏览系统中利用基于KML的专题符号实现定点符号法、分区图表法、质别底色法等专题图表示方法.通过实验说明KML在专题图的制作中具有巨大潜力,但同时也有一些重点问题需要解决.     

参数控制的地图符号编辑器设计

设计了一种实现参数控制的地图符号编辑器,可以对地图符号的每个图元、每个参数进行精确控制,而且点线面符号均采用基本图元组合而成,与具体的绘制语言无关,可以支持不同平台、不同环境的地图显示与输出。     

Assessment of changes in the area of the water conservation forest in the Qilian Mountains of China’s Gansu province, and the effects on water conservation

The Qilian Mountains water conservation forest in Gansu province is an important ecological barrier surrounding the oasis in China’s Hexi Corridor. The water they provide is the basis for the existence and sustainable socioeconomic development of those oases. As a result of unsustainable use of the water conservation forest until the 1980s, the oasis ecosystems of the Hexi region were seriously damaged, and the oasis areas experienced deterioration of their ecological environment. In this paper, Landsat images were used to monitor the temporal and spatial changes in area of water conservation in Qilian Mountains of China’s Gansu province and to assess the effect on water conservation by analyzed relationship between water conservation forest area, climatic data and hydrological data. The results showed that the forest covered 15.1% of the study area in 2007 and has followed different trends during the study period. From 1978 to 1990, the forest area decreased; however, from 1990 to 2007, the forest area increased, with a faster rate of increase from 1990 to 2000, and the rate of increase averaged 2,733.89 ha per year since 1990. The water conservation forest appears to play an important role in flood control, runoff regulation, the prevention of soil erosion, and water conservation; and these benefits increase with an increasing area of forest.     

风电场风速降尺度预报方法对比分析

使用中尺度数值天气预报业务模式9 km和3 km分辨率的模式输出产品,分别应用小尺度模式CALMET模式和双线性插值(BLI)方法将预报风速进行降尺度处理,并对比预报风速和风塔观测资料。结果表明：WRF模式9 km分辨率的模式输出经过CALMET模式降尺度以后得到的风速预报效果比3 km分辨率的模式输出略好。同时,由于中尺度数值预报模式分辨率本身较高,使用BLI也可以得到较好的风速预报。将风速分为0 m·s^-1≤风速<5 m·s^-1,5 m·s^-1≤风速<10 m·s^-1和风速≥10 m·s^-1共3个等级,检验3个风速等级的预报偏差百分比得出,CALMET模式和BLI方法对10 m·s^-1以上的大风的预报效果相对较差;如何对大风预报进行订正对风速预报准确率的提高具有重要的意义。     

Foraminifera as indicators of marine pollutant contamination on the inner continental shelf of southern Brazil

Analyses of living foraminiferal and environmental parameters near an outfall at Mar Grosso Beach (Laguna, SC, Brazil) demonstrate its usefulness as indicators of domestic sewage pollution. The low species diversity may be due to sand accumulation in the central part. Higher diversity was noted closer to the mouth of Laguna estuarine system where reduced salinity and higher temperatures indicate freshwater influence, suggesting a relationship between increased diversity and greater availability of terrestrial food. On the basis of foraminiferal diversity and average coliform count the higher values are closer to the mouth of the estuarine system and under the influence of the outfall. Due to the effect of local hydrodynamics, the particulate organic waste derived from the outfall does not settle down locally, and thus, do not accumulate nearby. Our hypothesis is that the fine material derived from the outfall is accumulating on the southwestern and northwestern parts of the beach.     

利用Lg波Q值反双台层析成像方法研究青藏高原南部地区的地壳衰减

首次基于2017—2019年西藏自治区区域台网27个宽频带固定台站记录的757次地震的波形资料,利用反双台法开展了青藏高原南部地区1 Hz的Lg波Q值层析成像研究.研究中采用3.5—2.4 km/s的速度窗截取了1981条Lg波,计算得到13543条路径上的Q值,测试了1°×1°和0.5°×0.5°网格下的棋盘格恢复情...     

新疆地区夏季平流层低层风场特征分析及数值模拟

利用2017年6—8月的FNL再分析资料分析了新疆地区夏季平流层低层风场的时空演变特征，开展了平流层低层风场的高分辨率数值模拟和检验。结果表明：新疆地区夏季平流层纬向风随时间的变化存在经向差异，同时准零风层开始和结束的时间也存在经向差异，准零风层开始时间南部地区早于北部地区，而准零风层结束时间则相反。整个夏季新疆地区上空的准零风层处于70～40 hPa之间，其高度随时间呈先降低而后升高的变化趋势。准零风层数值模拟结果表明，模拟的准零风层参数与探空资料分析结果相比二者存在一致的变化趋势，准零风层起始高度的平均绝对误差为467 m，该高度对应的风速均方根误差为1.75 m/s。     

天空光遮挡法水体光谱测量便携版漂浮式光学浮标研发与应用

离水辐亮度Lw(Water-leaving radiance)是水色遥感现场观测中的关键物理量之一,由其计算获得的遥感反射率Rrs(Remote sensing reflectance)是水色遥感参数反演的最基本参数.天空光遮挡法SBA(Skylight-blocked approach)可以直接测量水体离水辐亮度,作...