基于“北斗一号”导航卫星通讯的滑坡实时监测系统研究

介绍了基于中国北斗一号导航通信卫星技术建立的滑坡实时监测系统。该系统由“野外信息采集监测站”、“数字化滑坡自动监测点”、“北斗导航卫星通信系统”和“地质灾害监测分析中心”四大组成部分。在我国有线和GPRS等通讯设施不发达地区,采用基于北斗卫星通讯技术进行滑坡等野外监测数据传输是一种有效的方式。     

基于GPS卫星测量的远距离滑坡监测应用研究

利用GPS进行远距监控滑坡区并做适用性的评估研究,整合系统中含供电系统(室内及室外电源设置)、无线传输(利用GSM传输)、GPS资料后处理软件及监控软件等。所组合的系统将应用在某滑坡区,进行长时间持续监测。试验方式包含现场模拟试验、滑坡模拟测试,同时以远近两不同距离的主控站来评估此监测系统因基线长短不同所造成的精度影响,以期能通过此研究提出GPS监测系统设置的经验。根据研究成果指出,GPS监测系统应用在滑坡监测上可行,利用无线传输(GSM)可成功将现场的资料传给远程的操作者。试验结果显示,利用近基站观测可提高观测的精度及解算的成功率,但不论在远基线或近基线的试验,GPS监测系统的精度均可达到公分等级。     

基于SLOPE／W的汾离高速公路靳家庄1^#滑坡研究

汾(阳)-离(石)高速公路是青岛至银川国道主干线在山西境内的重要路段。文章以汾离高速公路靳家庄1#滑坡为研究对象,从岩性条件、地质构造及地下水等方面详细分析了滑坡的成因。应用基于刚体极限平衡理论的SLOPE/W程序,对滑坡的稳定性进行分析与计算。结果表明:该滑坡在天然状态下,整体处于稳定状态;在工程状态下,受水动力条件的变化以及人为活动的影响,易发生复活。为设计人员提供了参考。     

广州禽流感流行的气象条件分析

2003年底到2004年初在中国及其周边国家和地区爆发了高致病性禽流感,它使得这些地区几百万的家禽生病,甚至出现了人体感染死亡的现象,其危害巨大。运用对比分析的方法,对广州地区禽流感流行期间的天气形势和气温、空气湿度、风速等气象要素变化情况进行了分析,发现在2004年1月中旬至2月上旬禽流感高发期,广州地区呈现出低温高湿的气候特点,得出低温高湿的气象条件对该地区禽流感的发生和传播非常有利的结论,而2004年2月中旬以后该地区气温回升、光照充足的气象条件则抑制了禽流感的传播。     

四川省宣汉县天台乡特大型滑坡分析

2004-09-05四川省宣汉县天台乡发生一处特大型暴雨滑坡。滑坡体积约3 000×104m3,造成严重灾害,堵河形成堰塞湖,使上游集镇被淹没。对滑坡特征、形成机理及发展趋势进行了分析,提出了防治措施。     

上海地区高温过程中局地气候区尺度城市热岛特征分析

本文以超大城市上海为研究对象,选取2017年7月为夏季代表月,利用自动气象站网观测得到的逐小时气温和风速数据,基于局地气候分区方法分析了上海市各局地气候区(Local Climate Zone,LCZ)在不同天气条件下的气温和城市热岛强度(Urban Heat Island Intensity,UHII)时空特征及其成因。结果表明:由于城市几何形态、建筑材料、表面不透水面占比以及人类活动的不同,上海市夏季典型月各LCZ的气温和UHII表现出明显差异,在高温日,UHII日变化曲线可以分为"W "型、浅" U"型、"V"型、日间型和平稳型这五类。城市建筑形态对城市风、热环境具有较为复杂的影响,UHII与天空可视因子(Sky View Factor,SVF)的相关系数在00时(北京时,下同)为负,而在12、16时为正,这是由于建筑物对城市冠层内的辐射传输的影响和建筑物的热量储存导致的;城乡风速之比与SVF在00、12和16时都为正相关,说明了高大密集的建筑物对风速有衰减作用,同时风速通过影响大气的平流输送进一步影响UHII。     

Effects of Time-dependent Moisture Content of Surface Sediments on Aeolian Transport Rates Across a Beach,Wildwood, New Jersey,U.S.A.

A one-day field investigation on an unvegetated backbeach documents the importance of surface sediment drying to aeolian transport. Surface sediments were well sorted fine sand. Moisture content of samples taken in the moist areas on the backbeach varied from 2·9 to 9·2 per cent. Lack of dry sediment inhibited transport prior to 08:50. By 09:10 conspicuous streamers of dry sand moved across the moist surface. Barchan-shaped bedforms, 30 to 40 mm high and composed of dry sand (moisture content <0·10 per cent), formed where sand streamers converged. The surface composed of dry sand increased from 5 per cent of the area of the backbeach at 09:50 to 90 per cent by 12:50 Mean wind speeds were beetween 5·6 and 8·6 m s⁻¹ at 6 m above the backbeach. Corresponding shear velocities were always above the entrainment threshold for dry sand and below the threshold for the moist sand on the backbeach. Measured rates of sand trapped (by vertical cylindrical traps) increased during the day relative to calculated rates. The measured rate of sand trapped on the moist foreshore was higher than the rate trapped on the backbeach during the same interval, indicating that the moist foreshore (moisture content 18 per cent) was an efficient transport surface for sediment delivered from the dry portion of the beach upwind. Measured rates of sand trapped show no clear relationship to shear velocities unless time-dependent surface moisture content is considered. Results document conditions that describe transport across moist surfaces in terms of four stages including: (1) entrainment of moist sediment from a moist surface; (2) in situ drying of surface grains from a moist surface followed by transport across the surface; (3) entrainment and transport of dry sediment from bedforms that have accumulated on the moist surface; and (4) entrainment of sand from a dry upwind source and transport across a moist downwind surface. © 1997 John Wiley & Sons, Ltd.     

机载激光雷达在汶川地震应急响应中的若干关键问题探讨

就机载激光雷达在"5·12"四川地震灾区快速获取数据的若干关键问题进行了探讨.介绍了机载激光雷达的一般技术以及数据处理基本流程,对影响数据获取和最后成果精度的几个普遍问题进行了讨论,根据这次四川灾区的实际情况,比较详细介绍了数据获取和处理的一些关键技术问题.这些问题的探讨,对于机载激光雷达在中国广大西南地区的推广应用以及激光雷达在应急响应中的应用,有较好的参考价值.     

Quaternary lacustrine deposits in a high-energy semi-arid mountain environment,Karakoram Mountains,northern Pakistan

Impressive Quaternary lacustrine deposits are present as terrace remnants throughout the Karakoram Mountains, northern Pakistan. They are mainly the result of damming of drainage systems during glacial advances or by catastrophic mass movement deposits. The longevity of most lakes is relatively short, in the order of years to tens of years, but sedimentation rates are extremely high as a consequence of the high sediment loads within the rivers. This results in deposits that frequently exceed 10 m in thickness. The sediments comprise dominantly planar bedded, massive and, less commonly, planar laminated, silts, comprising detrital quartz, feldspar, mica, calcite, chlorite and illite. A facies model for lacustrine sedimentation in a high-energy semi-arid high mountain region is presented, using case studies from a glacially dammed palaeolake (Glacial Lake Gilgit) and a debris-flow dammed palaeolake (Lake Serat). The rapid deposition and absence of organic material restricts the usefulness of these lacustrine sediments as proxies for palaeoenvironmental reconstruction, but they are helpful in reconstructing the former extent of glaciers and illustrating the importance of high-magnitude–low-frequency events, such as landsliding, as formative processes contributing to the evolution of the Karakoram landscape.     

三峡库区坡地地貌过程的速率

在重庆奉节至湖北巴东一带三峡库区,存在两类坡地,分别是深层风化坡地与崩积—残坡积坡地。这两类坡地上,堆积物的稳定性差,表现为剥蚀、堆积的速率大。堆积物的累积速率可粗略地依据热释光年龄来估计。据此我们推测深层风化坡地的浅层滑坡周期大约是1.5ka,对应的堆积速率大约是33cm/ka。崩积—残坡积坡地上主要的陡崖崩塌发生周期是40ka⁶0ka,坡地中部的累积速率大约是4cm/ka。在崩积—残坡积坡地上常见生长的树木因堆积物蠕滑而变形,树木变形程度反映了蠕滑速率,据此估算的蠕滑速率是非常可观的,这既是坡地中部的剥蚀速率,可能也在一定程度上反映了坡地下部堆积物的物质供应速率。这些认识可能对滑坡与水土流失的治理有参考价值。