河北沿海海侵灾害初探

文中以包含海进、海岸侵蚀和海水入侵的广义“海侵”概念,论述河北沿海地区海侵现状及其危害,探讨海侵产生的自然原因和人为活动的影响,在此基础上,评估海侵发展趋势。     

Development of gullies and sediment production in the black soil region of northeastern China

Gully erosion is an important environmental hazard in the black soil region of northeastern China. It is a primary sediment source in the region which needs appropriate soil conservation practices. Gully incision in rolling hills typical of this region was monitored using real-time kinematic GPS to assess the rates of gully development and the resultant sediment production. From 2002 to 2005, gully heads in the study area retreated between 15.4 and 33.5 m, giving an average retreat rate of 8.4 m yr^− 1. Field measurements showed that total sediment production due to gully erosion during the three years ranged between 257 and 1854 m³ yr^− 1, which is equivalent to 326 to 2355 t yr^− 1, with gully-head retreat accounting for 0 to 21.7% (4.4% in average). The sediment delivery ratio was especially high during the summer rainy season (56% in average). Sediment production by ephemeral gullies and permanent gullies was 1.5 times greater than that from surface erosion. Gully heads retreated faster in the spring freeze–thaw period than in the summer. The stage of gully development could be identified based on short-term changes in the gully erosion rate.     

面向未来的海面变化研究

长期以来以地质时期海面变化过程等理论性研究为主要方向的海面变化研究经过７０年代在观念、方法和资料积累方面的突破，自８０年代初期以来进入了以“面向未来”为基调的成熟发展的新阶段，出现了一大批关于未来海面变化幅度及其影响和对策的研究成果，形成了较为完整的研究体系。９０年代初以来的几年间，世界海面研究的活跃领域是地质历史时期（例如ＬＧＭ，５ｅ等阶段）的海面实况、极地冰原对气候变化的反应、海面控制原理、海面模型以及绝对海面的航天测量技术与应用等方面。这一情况在一定程度上体现了“预测热”之后的“冷思考”。中国海面变化研究近年来取得了令世人瞩目的迅速发展，今后应注意引进先进技术方法，加强学科间的交叉合作，发掘自身的优势，向纵深发展     

GPS卫星运动状态算法及其软件实现

确定卫星的位置和速度是GPS定位导航的基础,以二体问题为基础,介绍了卫星运动状态的计算方法,建立了计算卫星实时位置、速度的数学模型,并运用C 语言实现了算法,证实了算法的正确性。     

利用决策级融合进行遥感影像分类

提出了一种基于决策级融合的遥感影像分类方法。该方法对遥感影像特征以最大似然分类器进行预分类,应用Adaboost算法将分类的结果进行决策级融合,实现影像的分类。实验结果表明,该方法的分类精度较传统分类方法有明显的提高。     

RTK技术在老挝甘蒙省钾盐矿勘查区地形图修测中的应用

以老挝人民民主共和国甘蒙省钾盐矿勘查区1∶50000地形图修测项目实例,介绍GPS RTK技术的基本原理和工作流程,总结出这种技术的优势所在以及实践操作中应该注意到的问题。     

青藏高原古人类的艺术创作——基于中更新世手脚印形态分析

在第二次青藏科考过程中,作者在西藏自治区拉萨市邱桑村的古泉华沉积上新发现了由5个手印和5个脚印组成 “岩面艺术” （parietal art）。对这一“岩面艺术”进行解剖学测量、3D 模型模拟、铀系测年和手脚印形态分析后,得到以下认识：① “岩面艺术”是在泉华没有成岩之前由古人类有意压上去的;② “岩面艺术”所在岩层的U/Th年代为226~169 ka B.P.,这其中包含一个手指印岩层的表面直接年龄（207~188 ka B.P.）;③ 这一发现是迄今为止发表的古人类在青藏高原上活动的最早记录之一,也为古人类适应高寒、低氧环境提供了新的证据;④ 此岩面艺术是目前世界上已知的最古老的艺术,上面的手印也是古人类留下的最早的手印;⑤ 这一原始的岩面艺术表明,创作它的古老人种可能具有一定的认知和空间感知能力,此岩面艺术的发现也将有可能改写人类艺术史,并且加深我们对已消失的古人类认知水平的认识。     

Exploring the sensitivity of coastal inundation modelling to DEM vertical error

As sea level is projected to rise throughout the twenty-first century due to climate change, there is a need to ensure that sea level rise (SLR) models accurately and defensibly represent future flood inundation levels to allow for effective coastal zone management. Digital elevation models (DEMs) are integral to SLR modelling, but are subject to error, including in their vertical resolution. Error in DEMs leads to uncertainty in the output of SLR inundation models, which if not considered, may result in poor coastal management decisions. However, DEM error is not usually described in detail by DEM suppliers; commonly only the RMSE is reported. This research explores the impact of stated vertical error in delineating zones of inundation in two locations along the Devon, United Kingdom, coastline (Exe and Otter Estuaries). We explore the consequences of needing to make assumptions about the distribution of error in the absence of detailed error data using a 1 m, publically available composite DEM with a maximum RMSE of 0.15 m, typical of recent LiDAR-derived DEMs. We compare uncertainty using two methods (i) the NOAA inundation uncertainty mapping method which assumes a normal distribution of error and (ii) a hydrologically correct bathtub method where the DEM is uniformly perturbed between the upper and lower bounds of a 95% linear error in 500 Monte Carlo Simulations (HBM+MCS). The NOAA method produced a broader zone of uncertainty (an increase of 134.9% on the HBM+MCS method), which is particularly evident in the flatter topography of the upper estuaries. The HBM+MCS method generates a narrower band of uncertainty for these flatter areas, but very similar extents where shorelines are steeper. The differences in inundation extents produced by the methods relate to a number of underpinning assumptions, and particularly, how the stated RMSE is interpreted and used to represent error in a practical sense. Unlike the NOAA method, the HBM+MCS model is computationally intensive, depending on the areas under consideration and the number of iterations. We therefore used the HBM+ MCS method to derive a regression relationship between elevation and inundation probability for the Exe Estuary. We then apply this to the adjacent Otter Estuary and show that it can defensibly reproduce zones of inundation uncertainty, avoiding the computationally intensive step of the HBM+MCS. The equation-derived zone of uncertainty was 112.1% larger than the HBM+MCS method, compared to the NOAA method which produced an uncertain area 423.9% larger. Each approach has advantages and disadvantages and requires value judgements to be made. Their use underscores the need for transparency in assumptions and communications of outputs. We urge DEM publishers to move beyond provision of a generalised RMSE and provide more detailed estimates of spatial error and complete metadata, including locations of ground control points and associated land cover.     

GPS automatic monitoring system for outside deformation of Geheyan Dam on the Qingjiang River

In this paper, the background of developing GPS Automatic Monitoring System for outside deformation of Geheyan Dam is described concisely. The framework, precision and features of the system are stated in detail. Finally, the prospective application of the system is introduced.