An experimental investigation of the effects of thawed soil depth on rill flow velocity     

Xiaofeng Gao  Xiaonan Shi  Tingwu Lei  Huaqing Liu  Jiahui Yang 《水文研究》2021,35(2):e14043

Water flow velocity is an important hydraulic variable in hydrological and soil erosion models, and is greatly affected by freezing and thawing of the surface soil layer in cold high-altitude regions. The accurate measurement of rill flow velocity when impacted by the thawing process is critical to simulate runoff and sediment transport processes. In this study, an electrolyte tracer modelling method was used to measure rill flow velocity along a meadow soil slope at different thaw depths under simulated rainfall. Rill flow velocity was measured using four thawed soil depths (0, 1, 2 and 10 cm), four slope gradients (5°, 10°, 15° and 20°) and four rainfall intensities (30, 60, 90 and 120 mm·h⁻¹). The results showed that the increase in thawed soil depth caused a decrease in rill flow velocity, whereby the rate of this decrease was also diminishing. Whilst the rill flow velocity was positively correlated with slope gradient and rainfall intensity, the response of rill flow velocity to these influencing factors varied with thawed soil depth. The mechanism by which thawed soil depth influenced rill flow velocity was attributed to the consumption of runoff energy, slope surface roughness, and the headcut effect. Rill flow velocity was modelled by thawed soil depth, slope gradient and rainfall intensity using an empirical function. This function predicted values that were in good agreement with the measured data. These results provide the foundation for a better understanding of the effect of thawed soil depth on slope hydrology, erosion and the parameterization scheme for hydrological and soil erosion models.  相似文献   

地质文化村:科学内涵、建设内容与实施路径     

丁华  张茂省  栗晓楠  苟青青  孙萍萍 《地质论评》2020,66(1):180-188

伴随着"生态文明"、"乡村振兴"等国家战略的提出,地质文化村成为拓展服务领域、促进地质工作与社会经济发展融合的重要抓手。本文以地质文化村的六维属性为切入点,探讨了地质文化村的空间载体、建设主题、利益主体、主要功能、行为准则、价值导向等内涵,提出地质文化村是以村域为空间载体,以突出"地质+"或"+地质"文化为主题,以共建共享为发展模式,以多元化功能为特征,以"轻质建设"和"生态旅游"为基准,以人地关系和谐为目标的特色村落。建设重点应以乡村五大振兴为总纲,围绕基础设施和公共服务体系、地质文化产品IP、高效产业及项目、多元人才体系、地质保护措施、文化村管理机构等方面开展;未来应通过强化规划衔接、制定行业标准、开展全国试点、加大资金投入、搭建宣传营销平台和进行系统培训等路径,促进地质文化村的健康持续发展。  相似文献   

车辆碾压作用下戈壁地表起尘浓度   总被引：1，自引：1，他引：0  

孟小楠  严平  王振亭  董苗  王勇 《中国沙漠》2019,39(1):80-87

通过野外观测车辆碾压作用下戈壁地表PM₁₀释放浓度，探讨其主要影响因素。针对戈壁区砾石、砂砾、砂质和砂土4种路面类型，应用TSI粉尘仪多次重复观测车辆碾压产生的PM₁₀浓度，进而阐明碾压次数、车速和地表水分等因素对起尘浓度的影响。结果表明：4种路面的平均起尘浓度依次为5.339、9.089、16.944、50.251 mg·m^-3，是自然状态下的5~50倍；起尘浓度随碾压次数增多而增大，其中砂土路情况下的增长最显著；随土层厚度的增大呈现出幂函数的增长趋势；降雨后路面起尘浓度显著减小，且降雨量会影响降雨后起尘浓度的变化趋势。最后提出了针对性的建议和措施以减弱车辆碾压导致的戈壁地表起尘。  相似文献   

鲁西潘店地区矽卡岩型铁矿成矿规律初探   总被引：1，自引：0，他引：1       下载免费PDF全文

郝兴中  刘伟  臧凯  张学松 《山东国土资源》2018,34(7)

近年来,在鲁中隆起区西北部潘店地区的铁矿勘查工作取得了重大进展。该区发育有明显的航磁异常及航空重力异常,且具有"重磁同源性"特征;通过对航磁异常的分析,可分为李屯、潘店、大张和薛官屯4个次级磁异常。勘查工作表明,区内巨厚新生界覆盖层下发育有矽卡岩型铁矿床,总体表现为"地层、岩体和构造"联合控矿的特征,即铁矿体受控于奥陶纪马家沟群碳酸盐地层、中生代燕山晚期闪长岩体、以及地层与岩体接触处形成的各种类型(构造)接触带。区内铁矿体赋存位置多样,主要为接触带赋存式、断裂充填式、层间充填式、裂隙贯入式、捕虏体构造式等;其成矿时代为早白垩世(130~131Ma),与济南、莱芜、金岭地区矽卡岩型铁矿形成时代基本一致;铁矿物质主要来源于中—基性侵入岩体。在整体表现为具有(剩余)重力异常高值处、(化极)磁异常明显部位,以及高—低电阻率转换带的地段进行铁矿勘查工作较为有利。  相似文献   

青岛台体应变短周期气压系数变化原因探讨     

岳龙  徐清风  臧艺博  李志强  刘云  李炜  孙忠礼 《大地测量与地球动力学》2020,40(7):765-770

青岛台体应变短周期(小于128 min)气压系数2018-01出现阶变，通过对观测系统、台站周边施工情况、监测环境等逐项现场核实，排除观测系统、周边施工的影响。利用离散小波变换和回归分析发现，钻孔水位的气压系数与体应变气压系数同步阶变，结合台站钻孔施工当天体应变钻孔水位变化、体应变趋势变化、其他相邻台站水位气压系数变化等数据认为，台站钻孔施工是导致体应变气压系数变化的原因，并定性分析其变化机理。  相似文献   

基于自相似河网结构的河网消退系数Cs计算方法研究     

臧帅宏  李致家  黄迎春  李巧玲 《湖泊科学》2019,31(3):788-800

新安江模型河网汇流参数Cs对洪峰模拟影响较大，目前Cs的确定需依赖于大量的历史数据，因此Cs的确定成为无资料地区和资料匮乏区水文模型应用中亟需解决的棘手问题.本文基于参数的物理意义，通过自相似河网结构的假定，构建Cs与河网形态、流域下垫面特征的相关联系，提出基于河链蓄量方程的Cs估算方法，对半干旱、半湿润和湿润地区等不同水文气象分区的11个流域的Cs值进行推算并代入新安江模型中进行模拟，经比较发现，11个流域子流域Cs计算均值与新安江模型率定结果相近，说明该Cs计算方法是合理的.选取陈河、屯溪两个典型流域研究单元流域属性对Cs的影响，由结果可以看出Cs与流域面积、河链数、河宽呈正相关，与单元流域距离出口的远近呈负相关，这表明流域分块后各单元流域Cs值不一致，而新安江模型中采用相同Cs值对不同单元进行调节必然会造成汇流计算的误差.为进一步提高该方法在无资料地区的应用效果，将新安江模型汇流模块修改为每个单元使用对应的Cs计算值进行滞后演算，以陈河和屯溪流域为例采用新安江模型Cs率定值、Cs计算均值以及修改后新安江模型3种不同方案进行模拟比较，从模拟结果可以得出，修改后的模型具有明显优势，将模型参数与下垫面条件建立了联系，模型物理机制提高且参数的独立性增强，对于新安江模型在无资料地区的应用具有重要的指导意义.  相似文献   

Establishment and application of an intelligent treating method for oil spill identification     

TAN Liju  ZHAO Ruxiang  YIN Xiaonan  ZHANG Haijiang  WANG Jiangtao 《海洋学报(英文版)》2018,37(11):116-122

In the identifying process of an oil spill accident, manual integral and artificial visual comparison are commonly used at present to determine the oil spill sources, these methods are time-consuming and easily affected by human factors. Therefore, it is difficult to achieve the purpose of rapid identification of an oil spill accident. In this paper, an intelligent method of automatic recognition, integration and calculation of diagnostic ratio of Gas Chromatography-Mass Spectrometer (GC/MS) spectrum are established. Firstly, four hundreds of samples collected around the world were analyzed using a standard method and Retention time locking technology (RTL) was applied to reduce the change of retention time of GC/MS spectrum. Secondly, the automatic identification, integration of n-alkanes, biomarker compounds, polycyclic aromatic hydrocarbons and calculation of the diagnostic ratios were realized by MATLAB software. Finally, a database of oil fingerprints were established and applied successfully in a spill oil accident. Based on the new method and database, we could acquire the diagnostic ratios of an oil sample and find out the suspected oil within a few minutes. This method and database can improve the efficiency in spilled oil identification.  相似文献   

海水海砂混凝土双K断裂参数的确定   总被引：1，自引：1，他引：0  

臧朝会  杨树桐  金亮亮 《海洋工程》2019,37(4):142-150

采用尺寸为515 mm×100 mm×100 mm初始缝高比从0.1变化至0.8的三点弯曲梁试件,利用试验测得起裂荷载Pini、最大荷载Pmax及对应的裂缝口张开位移CMODc等参数,研究了缝高比a0/h对海水海砂混凝土双K断裂参数的影响。并以相同配合比的淡水河砂梁作为对照组,进一步研究了海砂海水混凝土双K断裂参数与普通混凝土之间的关系。结果发现海水海砂混凝土断裂参数在a0/h=0.25～0.7范围内时可以认为是一常数;海水海砂混凝土梁断裂参数比相同配合比情况下的淡水河砂梁大且对边界影响更加敏感。  相似文献   

The Impact of Urbanization on Groundwater Quantity,Quality,Hydrothermal Changes and Its Countermeasures     

Wanbin Huang  Chunhua Yan  Xiaonan Zhang  Guoyu Qiu 《地球科学进展》2020,35(5):497-512

Groundwater, as a drinking water source for nearly one third of the world’s urban population, plays a strategic role in the development of urbanization. The object of this study is urban areas with the largest demand for water resources, the heaviest load of groundwater pollution and the most intense development of underground projects. This study sorted out the eco-hydrological problems such as the variation of the groundwater hydrological process, the groundwater pollution, and the urban heat island of groundwater in urban areas under the background of urbanization. Furthermore, the mechanism of changes in the quantity, quality and heat of groundwater was also systematically analyzed, and the intrinsic interaction among these three factors was revealed. The study showed that changes in land use and land cover caused by the urbanization are the main reasons for the variation of groundwater hydrological process. The pollution load of urbanization construction and domestic production waste has aggravated the deterioration of groundwater quality. The increase in vertical heat flux caused by urbanization gives rise to the warming of groundwater. By summarizing the eco-hydrological problems and causes of groundwater in urbanized areas, several suggestions were proposed: \mathrm{①} Establishing the evaluation method and system of urban groundwater resources; \mathrm{②} Speeding up the technological breakthroughs of groundwater pollution control; \mathrm{③} Improving the regional control strategies for groundwater pollution; \mathrm{④} Optimizing the allocation of groundwater resources. This study will provide the theoretical basis and technical support for ensuring urban water safety, building ecological civilized cities and further promoting the sustainable development of economy and society.  相似文献   

ASO-S卫星工程科学应用系统的数据库设计          下载免费PDF全文

葛蕴翊  黎辉  黄宇  李敬伟  雷仕俊  藏京京  苏杨  封莉  李友平  李瑛  徐遵磊  李翔 《天文学报》2020,61(4):46

先进天基太阳天文台(Advanced Space-based Solar Observatory, ASO-S)卫星是我国首颗太阳观测卫星, 主要观测太阳耀斑和日冕物质抛射以及产生它们的磁场结构. ASO-S卫星的科学应用系统是科学卫星工程的6大系统之一, 它连接科学用户和卫星数据, 为将卫星的科学数据转化为科学成果提供保障. 科学应用系统的数据库是连接软件与海量数据的枢纽, 为科学数据生产和用户服务及运行提供数据层的支撑. 介绍了科学应用系统的数据库架构设计、数据库的选择以及数据库性能优化和表样例. 这里的数据库包括观测计划、工程参数、运维日志、科学数据、定标数据和特征事件识别等数据库. 这些数据库的建设将为ASO-S卫星工程科学应用系统的顺利运行提供数据支撑, 也可以为未来其他科学卫星类似数据库的搭建提供参考和借鉴.  相似文献