中国遥感技术在考古中的应用与发展   总被引：4，自引：0，他引：4  

聂跃平  杨林 《遥感学报》2009,13(5):952-970

遥感技术的日新月异以及考古学的新目标、新需要不断出现, 利用遥感技术进行田野考古研究的工作已经取得长足进展。回顾了遥感考古的历史, 介绍了遥感技术在大遗址探测中的优势与作用, 以当前遥感考古与虚拟考古研究为例, 对遥感考古发展中面临的问题进行了概述。  相似文献   

徒步穿越考察世界第一大峡谷最新成果   总被引：4，自引：0，他引：4  

杨逸畴 《山地学报》1999,17(3)

介绍了人类首次徒步穿越和科学考察雅鲁藏布大峡谷的最新成果。  相似文献   

白鹤滩水电站峡谷地形区的风特征研究     

尹晔  白爱娟  刘炙明  张敏  白锦丰 《热带气象学报》2024,(2):178-188

位居世界第二大的白鹤滩水电站地处金沙江下游峡谷区,频繁的大风给水电站建设和运行带来了严重影响。掌握水电站坝区大风变化规律,评估峡谷地形对风速的作用,有利于基于周围风场监测和预警峡谷区大风。根据水电站及周边观测资料,对坝区风的变化特征和峡谷地形作用进行了分析。(1)峡谷区最高频率的风向和最大平均风速的风向均为顺着峡谷的偏南风或偏北风,且偏北风频率达55%以上,峡谷锁定了流经气流。(2)坝区大风多发生在干季11月—次年5月,且夜间至清晨大风频率比日间高。干季峡谷风效应强,尤其在19时—次日08时。雨季峡谷风效应降低,局地山谷风增强,表现为山风比谷风持续时间长,08时和18时是山风和谷风交替时间。对应干季和夜晚大风频繁,说明峡谷风效应是影响大风的关键因子。(3)通过狭管效应分析马脖子和葫芦口大桥两个站之间的风速关系,表明峡谷地形使马脖子站风速加强为葫芦口大桥站的1.27倍。利用多种拟合方法建立的两站风速关系表明,当葫芦口大桥站为5m·s-1以下低风速,各方法都难以拟合峡谷区的风速,当风速在5.0～11.5m·s-1时,狭管效应对风速拟合最优,准确率超过70%,对11.5m·s-1以上强风速,多项式拟合效果较优,准确率接近65%。  相似文献   

Megabenthic diversity patterns and community structure of the Blanes submarine canyon and adjacent slope in the Northwestern Mediterranean: a human overprint?     

Eva Ramirez-Llodra  Joan Baptista Company  Francisco Sardà  & Guiomar Rotllant 《Marine Ecology》2010,31(1):167-182

The composition and structure of megabenthic communities in the Blanes canyon and adjacent open margin (Northwestern Mediterranean) were studied. The aim was to assess the effect of the canyon and commercial fishing intensity on the community composition and structure of benthic megafauna by (i) describing the megabenthic community composition, (ii) quantifying faunal abundance and biomass and (iii) describing community structure with MDS analyses and biodiversity indices. The results are compared between three sites (canyon head, canyon wall and open margin) located between 435 m and 700 m. Samples were collected using a commercial bottom trawl between April 2003 and March 2004. These sites are exploited by the local fishing fleet that targets the rose shrimp Aristeus antennatus . A total of 131 megabenthic species were identified from the three sites, with fishes and decapod crustaceans being the most speciose, most abundant and of higher biomass. The species richness, abundance and biomass of non-crustacean invertebrates were low. There were no significant differences in total abundance and biomass between the three sites. However, community structure analysis suggests that the open margin community is significantly different from the canyon head and canyon wall, with a lower species richness, lower diversity and lower evenness. The open margin community also reflects a higher degree of disturbance compared to the two canyon habitats. The results indicate that there is a canyon effect on the community structure of benthic megafauna, but this may be modulated by differing fishing pressure, which adds an additional factor to margin heterogeneity.  相似文献   

Numerical and experimental studies on flow and pollutant dispersion in urban street canyons   总被引：1，自引：0，他引：1  

姜瑜君  姜瑜君  桑建国  张伯寅 《大气科学进展》2007,24(1):111-125

In this study numerical simulations and water tank experiments were used to investigate the flow and pollutant dispersion in an urban street canyon. Two types of canyon geometry were tested. The studies indicate that in a step-up notch canyon （higher buildings on the downstream side of the canyon）, the height and shape of the upstream lower buildings plays an important role in flow pattern and pollutant dispersion, while in a step-down notch canyon （lower buildings on the downstream side）, the downstream lower buildings have little influence. The studies also show that the substitution of tall towers for parailelepiped buildings on one side of the canyon may enhance the street ventilation and decrease the pollutant concentration emitted by motor vehicles.  相似文献   

基于水下自主航行器(AUV)的神狐峡谷谷底块体搬运沉积特征及其对深水峡谷物质输运过程的指示   总被引：2，自引：0，他引：2  

刘铮  陈端新  朱友生  张广旭  董冬冬 《海洋地质与第四纪地质》2021,41(2):13-21

海底峡谷是陆源物质向深海运移的重要通道.对于远离陆地的海底峡谷,通常认为浊流是物质搬运的主要营力.受限于探测精度和复杂作业环境影响,使用常规地球物理资料对深水海底峡谷尤其是对谷底沉积体的形态和结构特征的刻画不够精细.基于水下自主航行器(AUV,Autonomous Underwater Vehicle)采集的高分辨率多...  相似文献   

基于百度街景的SVF计算及其在城市热岛研究中的应用     

冯叶涵  陈亮  贺晓冬 《地球信息科学学报》2021,23(11):1998-2012

SVF（Sky View Factor）是描述城市辐射和城市热环境的有效指标之一,是研究城市热岛的重要几何参数,如何快速准确地计算大规模的SVF对城市形态和城市气候研究具有重要意义。已有研究发现,SVF与热岛强度具有强烈关系,但以往研究存在争论和局限性。本研究采用百度全景静态图,基于深度学习,使用Deeplabv3+模型对天空范围进行探测,提出一种SVF自动计算方法,并用该方法计算上海市中心城区的SVF分布。本研究引入局地气候分区（Local Climate Zones, LCZ）,将大规模、精确的SVF结合每个地块具体的土地利用和建筑情况进一步用于SVF与热岛强度的关系研究。实验结果表明,在不同场景下,Deeplabv3+模型都能对天空范围进行有效探测（MIOU=91.64%）;本文方法计算的SVF与鱼眼照片计算的SVF具有令人满意的一致性（R²=0.8869）;在不同区域,SVF与热岛强度的关系不同,对于LCZ5开敞中层建筑,最高相关系数为0.68,对于LCZ1紧凑高层建筑,最高相关系数为-0.79。本文SVF计算方法在上海市中心城区的成功应用,验证了在中国高密度和复杂的城市环境中使用街景图像计算大规模SVF的可行性,此外本文基于区域化研究思想进一步研究了SVF与城市热岛的关系,弥补了以往此类研究的不足。  相似文献   

The proximal part of the giant submarine Wailau landslide, Molokai, Hawaii     

David A. Clague  James G. Moore 《Journal of Volcanology and Geothermal Research》2002,113(1-2)

The main break-in-slope on the northern submarine flank of Molokai at −1500 to −1250 m is a shoreline feature that has been only modestly modified by the Wailau landslide. Submarine canyons above the break-in-slope, including one meandering stream, were subaerially carved. Where such canyons cross the break-in-slope, plunge pools may form by erosion from bedload sediment carried down the canyons. West Molokai Volcano continued infrequent volcanic activity that formed a series of small coastal sea cliffs, now submerged, as the island subsided. Lavas exposed at the break-in-slope are subaerially erupted and emplaced tholeiitic shield lavas. Submarine rejuvenated-stage volcanic cones formed after the landslide took place and following at least 400–500 m of subsidence after the main break-in-slope had formed. The sea cliff on east Molokai is not the headwall of the landslide, nor did it form entirely by erosion. It may mark the location of a listric fault similar to the Hilina faults on present-day Kilauea Volcano. The Wailau landslide occurred about 1.5 Ma and the Kalaupapa Peninsula most likely formed 330±5 ka. Molokai is presently stable relative to sea level and has subsided no more than 30 m in the last 330 ka. At their peak, West and East Molokai stood 1.6 and 3 km above sea level. High rainfall causes high surface runoff and formation of canyons, and increases groundwater pressure that during dike intrusions may lead to flank failure. Active shield or postshield volcanism (with dikes injected along rift zones) and high rainfall appear to be two components needed to trigger the deep-seated giant Hawaiian landslides.  相似文献   

First in situ observations of the deep-sea carnivorous ascidian Dicopia antirrhinum Monniot C., 1972 in the Western Mediterranean Sea     

《Deep Sea Research Part I: Oceanographic Research Papers》2014

Dicopia antirrhinum C. Monniot, 1972 is a rare species of deep-sea ascidian belonging to the Family Octacnemidae, reported at depths of 1000–2500 m in European Atlantic waters. Adult individuals have never been reported before in the Mediterranean Sea, where only seven juvenile specimens were found in 1975 at 500 m water depth in the Central basin (Malta). The affinities of these specimens with D. antirrhinum were noted, but lack of some typical characters of the species in juveniles prevented a definite taxonomical identification. No other member of the Octacnemidae has ever been found in the Mediterranean. In this study we describe the sampling of an adult specimen of D. antirrhinum at around 1100 m water depth on the flank of the La Fonera (Palamós) canyon, Northwestern Mediterranean, confirming their presence in the Mediterranean Sea. We also observed 5 individuals of this species on their natural habitat with a Remotely Operated Vehicle (ROV). Our results highlight the potential occurrence of Octacnemidae, the presence of which has been largely overlooked, in several deep-sea canyon areas within the Western Mediterranean basin. These observations are important because they indicate the need for increased sampling effort with new technologies, such as ROVs, in ecologically relevant habitats such as canyons, in order to obtain a more accurate picture of deep-sea biodiversity in the Mediterranean Sea.  相似文献   

中国西南深切峡谷岸坡地应力场基本特征     

李华  李崇标  刘云鹏  韩刚  赵其华 《岩土力学》2016,37(Z1):482-488

基于西南地区10个大型水电工程95点空间应力测试数据与50点硐壁应力恢复法测试数据,统计分析了边坡地应力场随垂向、水平向深度变化规律,根据主应力量级、倾角变化规律分析边坡浅表部地应力场特征,探讨了西南深切峡谷地区边坡地应力场分布规律。研究表明,（1）边坡应力场在宏观上可划分为浅表部区(0～300 m)与深部区(>300 m);（2）浅表部区主应力量级、倾角波动较为剧烈,而深部区主应力量级、倾角较为稳定,其最大主应力介于15～30 MPa,中间主应力介于10～20 MPa,最小主应力介于5～12 MPa,最大、最小主应力倾角介于0°～30°,最大主应力约为最小主应力的1.5～3.5倍;（3）浅表部区地应力场具有由主应力较小、最大主应力倾角与坡角近平行转变为主应力急剧增高、最大主应力倾角变化不明显,继而转变为主应力量级、最大主应力倾角剧烈波动,最后逐渐转变与深部应力场近于一致的特征。  相似文献