金属矿山坑道重力及微动测量技术应用研究     

王建超  赵毅  曾友强  曾晖 《地质论评》2024,70(S1):137-138

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Analysis of the contributions of topographic,soil, and vegetation features on the spatial distributions of surface soil moisture in a steep natural forested headwater catchment          下载免费PDF全文

Wei‐Li Liang  Sheng‐Lun Li  Feng‐Xu Hung 《水文研究》2017,31(22):3796-3809

Surface soil moisture has been extensively studied for various land uses and landforms. Although many studies have reported potential factors that control surface soil moisture over space or time, the findings have not always been consistent, indicating a need for identification of the main factors. This study focused on the static controls of topographic, soil, and vegetation features on surface soil moisture in a steep natural forested headwater catchment consisting of three hillslope units of a gully area, side slope, and valley‐head slope. Using a simple correlation analysis to investigate the effects of the static factors on surface soil moisture at depths of 0–20 cm at 470 points in 13 surveys, we addressed the characteristics of surface soil moisture and its main controlling factors. The results indicated that the mean of surface soil moisture was in the decreasing order of gully area > valley‐head slope > side slope. The relationship between the mean and standard deviation of surface soil moisture showed a convex‐upward shape in the headwater catchment, a negative curvilinear shape in the gully area, and positive curvilinear shapes at the side and valley‐head slopes. At the headwater catchment and valley‐head slope, positive contributions of soil porosity and negative contributions of slope gradient and saturated hydraulic conductivity were the main controlling factors of surface soil moisture under wetter conditions, whereas positive contributions of topographic wetness index and negative contributions of vegetation density were the main controlling factors of surface soil moisture under drier conditions. At the side slope underlain by fractured bedrocks, only saturated hydraulic conductivity and vegetation density were observed to be the controlling factors. Surface soil moisture in the gully area was mainly affected by runoff rather than were static features. Thus, using hillslope units is effective for approximately estimating the hydrological behaviours of surface moisture on a larger scale, whereas dependency between the main static factors and moisture conditions is helpful for estimating the spatial distributions of surface moisture on a smaller scale.  相似文献   

ADCP比测试验的统计分析   总被引：1，自引：0，他引：1       下载免费PDF全文

吴炳昭  李占桥  孙辉 《海洋测绘》2010,30(6):74-76

比测试验是一种常用的海洋调查仪器综合检测方法,通过对移动载体ADCP的一次比测数据的统计与分析,指出可以用标准差和超差点合格比例来评价ADCP观测数据的合理性。  相似文献   

哈拉哈塘地区东河砂岩段-角砾岩段沉积模式探讨     

徐正华  马青  徐大宝  邬兰  徐智  杨春梅 《海洋地质译丛》2010,(1):26-30

塔北的哈拉哈塘地区是东河砂岩油气勘探的重点地区，该地区目前已发现并探明了东河塘和哈得4两个东河砂岩油气藏，油气储量丰富，显示出良好的勘探前景。基于哈拉哈塘地区东河砂岩段和角砾岩段的岩性段穿时沉积现象异常明显，根据层序地层学原理和方法对哈拉哈塘地区东河砂岩段一角砾岩段进行了重新分层和对比，在层序分层等时地层框架的基础上重新进行了东河砂岩段一角砾岩段沉积模式研究，弄清该地区地层分布规律、演化规律、砂体分布及储层分布规律对该地区的油气勘探具有重要指导意义。  相似文献   

Sensitivity of streamflow from a Himalayan catchment to plausible changes in land cover and climate     

Xing Ma  Jianchu Xu  Meine van Noordwijk 《水文研究》2010,24(11):1379-1390

Global climate change will likely increase temperature and variation in precipitation in the Himalayas, modifying both supply of and demand for water. This study assesses combined impacts of land‐cover and climate changes on hydrological processes and a rainfall‐to‐streamflow buffer indicator of watershed function using the Soil Water Assessment Tool (SWAT) in Kejie watershed in the eastern Himalayas. The Hadley Centre Coupled Model Version 3 (HadCM3) was used for two Intergovernmental Panel on Climate Change (IPCC) emission scenarios (A2 and B2), for 2010–2099. Four land‐cover change scenarios increase forest, grassland, crops, or urban land use, respectively, reducing degraded land. The SWAT model predicted that downstream water resources will decrease in the short term but increase in the long term. Afforestation and expansion in cropland will probably increase actual evapotranspiration (ET) and reduce annual streamflow but will also, through increased infiltration, reduce the overland flow component of streamflow and increase groundwater release. An expansion in grassland will decrease actual ET, increase annual streamflow and groundwater release, while decreasing overland flow. Urbanization will result in increases in streamflow and overland flow and reductions in groundwater release and actual ET. Land‐cover change dominated over effects on streamflow of climate change in the short and middle terms. The predicted changes in buffer indicator for land‐use plus climate‐change scenarios reach up to 50% of the current (and future) range of inter‐annual variability. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Effect of land‐use changes on nonpoint source pollution in the Xizhi River watershed,Guangdong, China     

Kai Xu  Yunpeng Wang  Hua Su  Jingxue Yang  Lili Li  Cang Liu 《水文研究》2013,27(18):2557-2566

The Annualized Agricultural Non‐point Source (AnnAGNPS) pollution model has been widely used to assess and predict runoff, soil erosion, sediment and nutrient loading with a geographic information system. This article presents a case study of the effect of land‐use changes on nonpoint source (NPS) pollution using the AnnAGNPS model in the Xizhi River watershed, eastern Pearl River Delta of Guangdong province, China. The land‐use changes in the Xizhi River watershed between 1998 and 2003 were examined using the multitemporal remote sensing data. The runoff, soil erosion, sediment transport and nutrient loading 1998 and 2003 were assessed using AnnAGNPS. The effects of land‐use changes on NPS were studied by comparing the simulation results of each year. Our results showed that (i) the NPS loadings increased when forest and grass land converted into paddy, orchard and farmland land, and population size and gross domestic product size as well as the usage amounts of fertilizer and pesticide in the entire watershed were firmly correlated with the NPS loadings; (ii) the land‐use change during fast urbanization in particular when other land types were converted into the development land and buildup land led to increasing of NPS pollution; and (iii) urban land expansion showed more important effects on total organic carbon (TOC) loading compared with nitrogen and phosphorus loadings. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Coupled finite‐element simulation of injection well testing in unconsolidated oil sands reservoir     

Bin Xu  Ron C.K. Wong 《国际地质力学数值与分析法杂志》2013,37(18):3131-3149

This paper presents a finite‐element (FE) model for simulating injection well testing in unconsolidated oil sands reservoir. In injection well testing, the bottom‐hole pressure (BHP) is monitored during the injection and shut‐in period. The flow characteristics of a reservoir can be determined from transient BHP data using conventional reservoir or well‐testing analysis. However, conventional reservoir or well‐testing analysis does not consider geomechanics coupling effects. This simplified assumption has limitations when applied to unconsolidated (uncemented) oil sands reservoirs because oil sands deform and dilate subjected to pressure variation. In addition, hydraulic fracturing may occur in unconsolidated oil sands when high water injection rate is used. This research is motivated in numerical modeling of injection well testing in unconsolidated oil sands reservoir considering the geomechanics coupling effects including hydraulic fracturing. To simulate the strong anisotropy in mechanical and hydraulic behaviour of unconsolidated oil sands induced by fluid injection in injection well testing, a nonlinear stress‐dependent poro‐elasto‐plastic constitutive model together with a strain‐induced anisotropic permeability model are formulated and implemented into a 3D FE simulator. The 3D FE model is used to history match the BHP response measured from an injection well in an oil sands reservoir. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

海产鱼类中异尖线虫酶消化检测技术的研究与应用     

许旭  黄维义  隋建新  林洪  鲜均章  励建荣  曹立民 《中国海洋大学学报(自然科学版)》2010,40(3)

以3种海鱼(牙鲆、狭鳕、鲱鱼)为样本,针对海产品中主要的致病性寄生虫-异尖线虫,开展了酶消化检测技术的研究.根据鱼肉消化前后干物质的质量变化设计了胃蛋白酶消化效率的计算方法,并按照鱼肉:消化液＝1:10 (g/mL)的反应比例,分别确定了酶水解鱼肉的最佳条件为:初始pH值为1.1,温度为37 ℃,酶活力为8 U/mL左右;消化后所得的虫体采用多重PCR方法替代传统的形态学观察进行种属鉴定,从而初步建立了基于酶水解-多重PCR的异尖线虫的酶消化检测体系.实际样本检测表明,该技术可以较为准确、快速地用于海产鱼类中简单异尖线虫(Anisakis simplex)和伪地新线虫(Pseudoterranova decipiens)的确证性检测.  相似文献   

Characterizing the hydraulic properties of unsaturated sand considering various porosities and drying‐wetting paths of the retention curve     

Kai‐yuan Ke  Yih‐Chi Tan  Chu‐Hui Chen  Hsien‐Tsung Lin 《水文研究》2013,27(4):592-604

Previous studies have shown that water retention curve (WRC) and the hydraulic conductivity vary because of changes of the void ratio or porosity of soil. However, limited documents pointed out the change of hydraulic properties of soil when compacted to different porosities while considering both of the drying and wetting processes of the WRC. This information is sometimes necessary for research like finger flow analysis or the occurrence of wetting and drying cycles as what would be seen in the field. Therefore, this study aims to examine the change of WRC characteristics with varied porosity considering both of the drying and wetting path in WRC by conducting a sand box experiment. Results show that the same type of sand compacted to various porosities have different hydraulic parameters. Hydraulic conductivities generally decrease with reduced porosities; shape parameter α of the van Genuchten equation (1980) linearly decreases with declining porosity and shape parameter n in a reversal manner for the sands of interest whether in the drying process or wetting process. The unsaturated properties of sand are further characterized by inspecting the variations of moisture content, matric suction and vertical displacement of soil body subject to periodic changes of the water level by another sand box experiment. The outcomes suggest that the saturated water content and residual water content are changing during the wetting–drying process, which can be an implication of the changed properties of WRC. The characteristics of volumetric deformation might be varied as well because of the observation of the dissimilar patterns of the changing vertical displacements among each wetting–drying process. Infiltration patterns of the sands also are identified through numerical modelling by introducing a constant infiltration flux from the surface followed by a no‐influx condition. Results indicate that less water accumulates in the sand near the surface for the sand compacted to higher porosity, but water can move deeper. Hydraulic conductivity is found as the prime factor dominating the evolvement of wetting fronts. However, shape parameters of water retention curves also affect the infiltration pattern to some extent. In addition, different sands with similar porosities can have quite different infiltrating characteristics. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Abrupt behaviours of streamflow and sediment load variations of the Yangtze River basin,China     

Qiang Zhang  Vijay P. Singh  Chong‐Yu Xu  Xiaohong Chen 《水文研究》2013,27(3):444-452

Monthly sediment load and streamflow series spanning 1963–2004 from four hydrological stations situation in the main stem of the Yangtze River, China, are analysed using scanning t‐test and the simple two‐phase linear regression scheme. Results indicate significant changes in the sediment load and streamflow from the upper reach to the lower reach of the Yangtze River. Relatively consistent positive coherency relations can be detected between streamflow and sediment load in the upper reach and negative coherency in the middle and lower reaches. Interestingly, negative coherency is found mainly for larger time scales. Changes in sediment load are the result mainly of human influence; specifically, the construction of water reservoirs may be the major cause of negative coherency. Accentuating the human influence from the upper to the lower reach results in inconsistent correlations between sediment load and streamflow. Decreasing sediment load being observed in recent years has the potential to alter the topographical properties of the river channel and the consequent development and recession of the Yangtze Delta. Results of this study are of practical significance for river channel management and evaluation of the influence of human activities on the hydrological regimes of large rivers. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献