风暴潮沿珠江河道上溯运动的数值模拟

采用动力学数值模式对风暴潮沿珠江河道上溯的个例进行了模拟,并就有关机制进行讨论.结果显示,风暴潮位是否沿珠江河道向北逐渐递增,和风暴强度有很大的关系,也和风暴登陆的路径有关;南海的热带气旋多数是西行的,这样就使本文研究的对象像是“过路”的风暴,伶仃洋的聚水面积不算大,加上蛛网般河网的分散作用,都使珠江一线的风暴增水很少超过2.5m.但即使这样规模的增水,也对河口平坦地区造成很大威胁.由于天文潮的耦合,以及浅水效应,风暴潮常有不同程度的变形.本文的模拟中,模式、参数和计算对象等早已选好,计算时只作了少许调整,就能得到较好的结果,说明模式是合理和可靠的.     

Towards a process-based biogeography of reindeer—scaling space,time, and organizational levels of space use

Due to increasing anthropogenic habitat alteration, fragmentation, and loss, the analysis of how, when, and why animals select particular habitats has become a central issue in ecology and biogeography. Animals adapt to spatiotemporal variability in resources either by tracking these resources or by plasticity in behavior to cover their needs, leading to three important implications: movement, temporal variation, and individual trade-offs leading to intra-species variability, all of which are directly linked to the use of space by animals. Based on GPS-tracking of domesticated reindeer in southern Norway, the authors addressed these issues by analyzing movement patterns and space use simultaneously across different temporal and organizational scales. Emerging information about the space use by reindeer was found explicitly linked to scaling relations, reflecting the matter of scale as having important functional implications rather than solely being a technical question of extent and resolution. Adding movement into the analysis of space use further advances the necessary functional perspective on space use. The authors conclude that scaling not only space but also time and the organizational level, in combination with accounting for different behavioral states, brings biogeography closer to a process-based view, rather than solely pattern-based view.     

基于高速摄像技术的推移质运动特征试验

在明渠中开展不同水流条件下低强度均匀沙平衡输沙试验,基于灰度相减方法分析整个床面推移质运动特征,以探寻紊流结构与推移质运动之间的作用机理。结果表明:①受水槽横向方向水流强度分布特征影响,推移质运动概率从水槽中线到两侧壁逐渐变小,且基本呈对称分布;②在紊流相干结构作用下,推移质床面在紊流低速条带区形成凸槽,高速条带区形成凹槽,推移质运动概率沿水槽横向方向存在高低相间的带状分区;③随摩阻雷诺数增大,相邻两推移质运动高概率区域的间距值变化范围为0.13~0.24倍水槽宽度,其值随摩阻雷诺数增大而增大;④不同水流条件下,推移质运动高概率区域间距值约为水深的2倍,这与流向涡模型吻合,表明流向涡是诱导床面出现凹凸相间形态的重要因素。     

江苏盐城大丰港西洋深槽冲淤变化特征

西洋深槽是大丰港赖以生存的重要航道。在野外地质调查实测资料的基础上,结合以往的地形资料,从典型断面、等深线、区域等不同角度综合分析了近年来西洋深槽的地形冲淤变化特征,发现西洋深槽近期整体处于基本稳定状态。调查成果已转化应用,为大丰港区港航规划和可持续开发建设提供了基础数据。     

基于数字剖面的河流阶地与新构造运动研究——以内蒙古西拉木伦河河流阶地为例

野外调查发现在内蒙古东部西拉木伦河流域存在12级阶地序列。利用数字剖面野外系统对该河流阶地剖面的记录完成全程数字化采集,并进行数字剖面桌面系统厚度自动计算和剖面图、柱状图自动生成,发现该阶地序列中T7、T8、T9保存完好,而时代最为古老的T12 根据基座玄武岩形成于上新世—早更新世的年龄,其形成时代应为上新世—早更新世。通过计算新构造运动抬升速率,将其形成、演化过程划分为6个阶段。数据表明,自中新世以来,该地区新构造运动存在一定的周期性,在总体上新构造运动的强度逐渐趋于缓和。     

Field investigation of surface sand and dust movement over different sandy grasslands in the Otindag Sandy Land,China

The characteristics of sand and dust movement over different sandy grasslands in China’s Otindag Sandy Land were explored based on field observations and laboratory analyses. Threshold wind speeds (the speed required to initiate sand movement) at a height of 2 m above the ground were estimated in the field for different surface types. Threshold wind speed above shifting dunes in the study area is about 4.6 m s⁻¹ at this height. This value was smaller than values observed above other surfaces, resulting in a greater risk of blowing sand above these dunes. Differences in sand transport rates (STR) as a function of the severity of desertification resulted primarily from differences in surface vegetation cover and secondarily from the soil’s grain-size distribution. STR increased exponentially with increasing near-bed wind velocity. Under the same wind conditions, STR increased with increasing severity of desertification: from 0.08 g cm⁻² min⁻¹ above semi-fixed dunes to 8 g cm⁻² min⁻¹ above semi-shifting dunes and 25 g cm⁻² min⁻¹ above shifting dunes. Vegetation’s affect on STR was clearly large. Different components of sand and dust were trapped over different lands: mostly sand grains but little dust were trapped above shifting dunes, but much dust was collected over semi-shifting and semi-fixed dunes. Human disturbance is likely to produce dust even from fixed dunes as a result of trampling by animals and vehicle travel. In addition, spring rainfall decreased the risk of sand and dust movement by accelerating germination of plants and the formation of a soil crust.     

基于数字剖面的河流阶地与新构造运动研究 ——以内蒙古西拉木伦河河流阶地为例

野外调查发现在内蒙古东部西拉木伦河流域存在12级阶地序列。利用数字剖面野外系统对该河流阶地剖面的记录完成全程数字化采集,并进行数字剖面桌面系统厚度自动计算和剖面图、柱状图自动生成,发现该阶地序列中T7、T8、T9保存完好,而时代最为古老的T12 根据基座玄武岩形成于上新世—早更新世的年龄,其形成时代应为上新世—早更新世。通过计算新构造运动抬升速率,将其形成、演化过程划分为6个阶段。数据表明,自中新世以来,该地区新构造运动存在一定的周期性,在总体上新构造运动的强度逐渐趋于缓和。     

地壳运动速度场的数据融合研究

针对速度场融合中公共点的筛选对求解参数的影响、转换参数随公共点个数的变化,以及六参数转换和七参数转换对结果精度的影响等问题进行了较为深入的研究.针对东亚地区的地壳运动问题,给出了合理的速度场融合方案,并对1997～2005年间的GPS观测结果进行了速度场融合,获得了东北亚地区现今地壳运动的统一速度场.     

新疆阿尔泰山东段冰碛物光释光测年研究

冰川是塑造地表形态最积极的外营力之一,对冰川地貌的年代学研究是重建古冰川发展史的关键,也是研究气候变化的重要途径。冰碛物是冰川作用的直接产物,代表过去发生的冰川事件,对冰碛物进行准确测年能够为重建古冰川的进退、理解区域古气候变化提供年代学支撑。本文在新疆阿尔泰山东段采集了8个冰碛物样品以进行光释光测年,利用单片再生剂量法对90~125 μm的石英颗粒进行等效剂量的测定。通过等效剂量值频率分布特征及De（t）坪区图分析得出大部分冰碛物的光释光信号晒退不彻底,所以利用一阶动力学公式对持续激发的光释光信号晒退曲线（CW-OSL）进行多组分拟合拆分,得到快速、中速、慢速3种组分,依据分离出的快速组分确定等效剂量值。研究结果显示,距今32 ka以来阿尔泰山东段区域在MIS3阶段、MIS2阶段、8.2 ka左右、全新世大暖期及新冰期等5个时段有冰川发育,冰川发育与气候变化密切相关。     

PIR传感网数据的几何代数建模与行为分析

现有基于PIR（Passive InfraRed）传感器数据的人体行为研究主要局限于运动时空分布、聚类等,对行为轨迹的重建和语义特征的解析相对较少,亟需发展新的建模与行为分析方法。本文尝试利用室内区域PIR传感器监测数据进行时空轨迹重构及其所揭示的运动语义特征研究。本文引入几何代数理论方法,构建传感器场景网络,实现了几何代数空间下动态网络的表达与路径计算,分析了人体运动特征及语义特征,建立最小语义单元,实现了空间数据到语义特征的转化,并可对个人和群体运动的空间区域特征和拓扑特征分析提供支撑。论文将传统PIR传感器网络分析从以几何、统计等为主的信号提取,转变为基于几何代数系统中不同类型代数结构的生成与转化问题,为诸如PIR传感网数据分析一类的非确定问题的求解提供了新的思路和数学基础,可为物联网GIS的构建提供借鉴。