盐城海岸带湿地景观格局变化研究   总被引：3，自引：0，他引：3  

王夫强  柯长青 《海洋湖沼通报》2008,(4)

利用4个时相的陆地卫星遥感影像及相关资料,在遥感和地理信息系统技术支持下,对盐城国家级自然保护区的核心区和缓冲区进行了景观格局分析。结果表明,从1988~2002年,淤泥质滩涂面积增长了13.33%;分形维数从1.0991上升到1.1166,蔓延度指数从76.4426下降到53.1142,表明研究区形状趋于规则,人为干扰程度增大,景观有破碎有上升的趋势,该边缘生境异质性在逐步增强;人类对滩涂的影响增加,逐渐成为影响该生态系统的主要力量。  相似文献   

Decomposition analysis on direct material input and dematerialization of mining cities in Northeast China     

Fangdao Qiu  Lianjun Tong  Huimin Zhang  Na Zhang 《中国地理科学(英文版)》2009,19(2):104-112

Material dematerialization is a basic approach to reduce the pressure on the resources and environment and to realize the sustainable development. The material flow analysis and decomposition method are used to calculate the direct material input (DMI) of 14 typical mining cities in Northeast China in 1995-2004 and to analyze the demateri-alization and its driving factors in the different types of mining cities oriented by coal, petroleum, metallurgy and multi-resources. The results are as follows: 1) from 1995 to 2006, the increase rates of the DMI and the material input intensity of mining cities declined following the order of multi-resources, metallurgy, coal, and petroleum cities, and the material utilizing efficiency did following the order of petroleum, coal, metallurgy, and multi-resources cities; 2) during the research period, all the kinds of mining cities were in the situation of weak sustainable development in most years; 3) the pressure on resources and environment in the multi-resources cities was the most serious; 4) the petro-leum cities showed the strong trend of sustainable development; and 5) in recent years, the driving function of eco-nomic development for material consuming has continuously strengthened and the controlling function of material utilizing efficiency for it has weakened. The key approaches to promote the development of circular economy of min-ing cities in Northeast China are put forward in the following aspects: 1) to strengthen the research and development of the technique of resources' cycling utilization, 2) to improve the utilizing efficiency of resources, and 3) to carry out the auditing system of resources utilization.  相似文献   

颗粒流沉积边程中的同沉积冲刷变形构造     

王新征 《地球科学与环境学报》2004,26(3):13-16

济阳拗陷坨147井沙三段岩心的颗粒流沉积中．存在一系列特殊的同沉积期变形构造。包括：颗粒流向下侵蚀。并沿纹层面挤入到下伏油页岩层中．形成伸长状的小砂体；砂楔上部的泥页岩薄层在后续流体的冲刷下向后翻卷变形；翻卷片被撕裂、断开混入到颗粒流中。并被流体拖曳变形；变形体被继续拖曳形成脉状分叉的拖曳痕。上述几种现象可以构成一个连续的变化序列，与油页岩的薄互层和颗粒流的流体是形成上述连续变形构造的重要条件。对这种现象的研究．有助于进一步了解重力流的冲刷、沉积过程。  相似文献   

The effects of rock fragments on hydrologic and hydraulic responses along a slope     

Kou‐Chan Hung  Ken'ichirou Kosugi  Tim Hau Lee  Takahisa Misuyama 《水文研究》2007,21(10):1354-1362

A model describing the three‐dimensional matrix flow along a slope with rock fragments or impermeable blocks was developed. The model was combined with modified Picard's iteration to ensure mass conservation in the unsaturated flow. We found that rock fragments obstruct water flow along the slope. The groundwater table must be raised to provide a sufficient pore water pressure gradient to facilitate water flow, but higher pore water pressure may induce slope failure. We also conducted a bench‐scale laboratory flume experiment to examine the effects of impermeable blocks on downstream seepage flow. In addition, a numerical experiment was conducted to examine how different arrangements of impermeable blocks affect downstream seepage flow and pore water pressure. This research demonstrated that the hydraulic phenomena were affected when impermeable blocks were present, and pore water pressure increased as the position of impermeable blocks was lowered. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

船行波对H-ADCP 影响分析研究     

《海洋技术学报》2024,(1)

作为当今世界上最先进的测流仪器，水平式声学多普勒流速剖面仪（Horizontal Acoustic Doppler Current Profiler，H-ADCP） 因其精度高、速度快等突出优势在河流中的应用越来越广泛，但在航运业发达地区，由于受船行波的影响，很难得到稳定可靠的流速数据，阻碍了H-ADCP在平原河网地区的应用和推广。目前技术上很难做到完全消除船行波的影响，本文将H-ADCP应用在平原河网地区对流速进行测量，并分析了船行波对测量精度的影响。从H-ADCP设备选型、测量和安装方式、测量预处理、数据后处理等多方面入手，可以有效消减船行波对H-ADCP 的影响，从而提高测流精度。同时，通过实验测量断面一天内平均流速变化情况，得到受船行波影响后的流速波形，然后采用数据处理手段，验证了所提方法的可行性。  相似文献   

Lateral flow thresholds for aspen forested hillslopes on the Western Boreal Plain,Alberta, Canada     

T. E. Redding  K. J. Devito 《水文研究》2008,22(21):4287-4300

To predict the long‐term sustainability of water resources on the Boreal Plain region of northern Alberta, it is critical to understand when hillslopes generate runoff and connect with surface waters. The sub‐humid climate (P ≤ ET) and deep glacial sediments of this region result in large available soil storage capacity relative to moisture surpluses or deficits, leading to threshold‐dependent rainfall‐runoff relationships. Rainfall simulation experiments were conducted using large magnitude and high intensity applications to examine the thresholds in precipitation and soil moisture that are necessary to generate lateral flow from hillslope runoff plots representative of Luvisolic soils and an aspen canopy. Two adjacent plots (areas of 2·95 and 3·4 m²) of contrasting antecedent moisture conditions were examined; one had tree root uptake excluded for two months to increase soil moisture content, while the second plot allowed tree uptake over the growing season resulting in drier soils. Vertical flow as drainage and soil moisture storage dominated the water balances of both plots. Greater lateral flow occurred from the plot with higher antecedent moisture content. Results indicate that a minimum of 15–20 mm of rainfall is required to generate lateral flow, and only after the soils have been wetted to a depth of 0·75 m (C‐horizon). The depth and intensity of rainfall events that generated runoff > 1 mm have return periods of 25 years or greater and, when combined with the need for wet antecendent conditions, indicate that lateral flow generation on these hillslopes will occur infrequently. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Regional hydrologic mapping of flows in stream networks     

Bahram Saghafian   《International Journal of Applied Earth Observation and Geoinformation》2009,11(5):317-323

River low flow (LF) is an important hydrological characteristic used in management of the quantity and quality of water resources. A common way to transpose at-station low flow quantiles to ungaged locations involves development of regional multivariate regression models. In site selection studies of water control facilities, need arises to automate the mapping of LF characteristics onto the stream network in a continuous manner. This would allow estimation of LF at any desired ungaged location. A mapping algorithm is introduced that determines the value of regression model's independent variables (input components) over the drainage area of each stream pixel and calculates the flow (output). The mapping algorithm relies mainly on the digital elevation model (DEM) and its derivatives, such as flow direction and flow accumulation. Furthermore, the contribution of each independent variable of the regional model to the total flow may be plotted to represent the flow profiles along the streams. A case study involving LF mapping in rivers of Gilan province, Iran, where LF quantiles are required for issuing water withdrawal permits as well as maintaining water quality standards, is also described in the paper. Overall, the maps and profiles of flow statistics in the region of interest provide convenient visualization and assessment tools for water resource and environmental engineers. The transposition algorithm may also be applied in regional mapping of other flow characteristics such as flood or average flows.  相似文献   

The generation and redistribution of overland flow on a massive oxic soil in a eucalypt woodland within the semi-arid tropics of North Australia     

Mike Bonell  John Williams 《水文研究》1986,1(1):31-46

There is a dearth of knowledge on the runoff processes of eucalypt woodland communities in the semi-arid tropics of Australia. The work was undertaken on a 100 m transect of a 0·8 degree hillslope typical of the ‘smooth plainlands’ of central-north Queensland. This paper introduces a new experimental design for measuring overland flow in such areas by way of a cascade system of unbounded runoff plots which allow the inputs and outputs between troughs to be calculated. Most storms generate overland flow. Time to overland flow ranges between 1 and 18 min where rain intensities are above 10mm hr⁻¹ and when the average detention storage of 3·6 mm is exceeded. The bare soil surfaces within the scattered grass understory control the runoff generation process through the temporal variability of field saturated hydraulic conductivity. The study demonstrated that overland flow is mainly redistributed over the freely-draining oxic soil. Some areas export more overland flow than they gain from upslope (runoff), others gain more overland flow than they export (runon). Over the study period only 2 per cent of total rain is transferred out of this 100 m transect as overland flow due to the short duration of storms, the relatively high soil permeability, and the low slope angle. The remainder adds to the large soil water store or deep drainage. The variability of runoff–runon over these ‘smooth plainlands’ highlights how results from bounded plots would be misleading in such areas.  相似文献   

井下双向流动阀防漏失技术在埕岛油田的应用     

秦豫海 《海洋地质译丛》2008,(3):78-80

埕岛油田位于渤海西南部极浅一浅海地区，是一个大型潜山披覆构造油田。随着埕岛油田开采力度加强，地层亏空十分严重，作业过程中的地层漏失是困绕埕岛油田油层保护的一大难题。据此介绍了胜利油田海上埕岛油田油层保护的一项新技术——井下双向流动阀防漏失技术的应用情况，阐述了井下双向流动阀的结构、原理以及应用后对油层保护所起到的作用。  相似文献   

A predictive numerical model for potential mapping of the gas hydrate stability zone in the Gulf of Cadiz     

R. Len  L. Somoza  C.J. Gimnez-Moreno  C.J. Dabrio  G. Ercilla  D. Praeg  V. Díaz-del-Río  M. Gmez-Delgado 《Marine and Petroleum Geology》2009,26(8):1564-1579

This paper presents a computational model for mapping the regional 3D distribution in which seafloor gas hydrates would be stable, that is carried out in a Geographical Information System (GIS) environment. The construction of the model is comprised of three primary steps, namely: (1) the construction of surfaces for the various variables based on available 3D data (seafloor temperature, geothermal gradient and depth-pressure); (2) the calculation of the gas function equilibrium functions for the various hydrocarbon compositions reported from hydrate and sediment samples; and (3) the calculation of the thickness of the hydrate stability zone. The solution is based on a transcendental function, which is solved iteratively in a GIS environment.The model has been applied in the northernmost continental slope of the Gulf of Cadiz, an area where an abundant supply for hydrate formation, such as extensive hydrocarbon seeps, diapirs and fault structures, is combined with deep undercurrents and a complex seafloor morphology. In the Gulf of Cadiz, the model depicts the distribution of the base of the gas hydrate stability zone for both biogenic and thermogenic gas compositions, and explains the geometry and distribution of geological structures derived from gas venting in the Tasyo Field (Gulf of Cadiz) and the generation of BSR levels on the upper continental slope.  相似文献