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   

地震异构云管理平台的技术架构设计     

郭凯  姜立新  刘晓雨  班世敏 《中国地震》2020,36(1):153-161

基于Open Stack的开源标准体系,结合中国地震台网中心和中国地震局第二监测中心的云基础设施现状,设计两级云管理架构,以异构云管理平台作为综合管理平台,纳管区域云管理平台,以统一门户的方式对地震行业云计算资源进行统一管理;通过容器化部署异构云管理平台,初步实现对地震行业云计算资源的统一监控和运行管理。  相似文献   

Hydrologic separation and their contributions to N loss in an agricultural catchment in hilly red soil region   总被引：1，自引：0，他引：1  

Wang  Yaji  Gao  Lei  Peng  Xinhua 《中国科学:地球科学(英文版)》2019,62(11):1730-1743

The impacts of hydrological processes on N loss is of great value to understand the N transport at catchment scale,which is far from clear. Rainfall, soil water, groundwater and stream water and their N concentrations were monitored from March 2017 to February 2018 in Sunjia agricultural catchment of the red soil critical zone. Objectives of this study were:(1) to determine the dynamics of N concentration of different waters and their N loads;(2) to assess their contributions to N load of streamflow in the paddy and upland mixed agricultural catchment. Our results showed that the N concentrations of soil water(4.8 mg L~(-1)) and groundwater(6.0 mg L~(-1)) were the highest, approximately 2 to 5 times higher than those of stream water(2.7 mg L~(-1)), rain water(1.7 mg L~(-1)) and irrigation water(1.2 mg L~(-1)). The N net loss of the catchment(38.2 kg ha~(-1) yr~(-1))accounted for 15% of the total fertilizer N input. Rainy season(April–June) was a high-risk period of N loss, contributing to more than one third of the total annual loss amount. Using end-member mixing analysis model(EMMA), we found groundwater(whose discharge accounted for 25% of the catchment streamflow) was an important source for the N loss in the agricultural catchment. Even in this catchment with coexisting upland and paddy field ecosystems, identified end-members could be used to predict the N load well(R~20.87, p0.001). These results can deepen our understanding of the relationship between hydrological process and N transport in the red soil critical zone and are also helpful to improve the water and fertilizer management in subtropical agricultural catchment.  相似文献   

桂林-阳朔地区DEM地形特征与岩性相关性分析及分类研究     

陈霄燕  潘军  邢立新  蒋立军  孙也涵  仲伟敬  范博文 《地球信息科学学报》2019,21(12):1867-1876

地形地貌是岩性解译的重要信息,地形因子作为描述DEM数字曲面几何特征的定量指标参数,可用来定量化表达不同岩性所在地区地形地貌特征。本文以桂林-阳朔地区为研究区,研究地形因子数学、地质意义,建立岩性与地形因子组合间的定量关联,进而实现岩石类型划分。本文基于ASTERGDEM提取坡度、起伏度等12个地形因子,在分析各个地形因子地质意义基础上,通过聚类分析及方差分析的多元统计分析方法,研究各岩性地形因子特性及其关联性,建立研究区岩性之间的定量差异;此外,利用因子分析方法研究岩性分类过程中的主导因素,确定适宜岩性分类方法以实现定量化岩性分类。实验结果表明：不同岩性、不同地形地貌的地形因子（组合）之间具有显著差异,基于因子分析得到的宏观地形复杂度指数（MTI）以及微观曲率指数（MCI）对岩石类型的分类精度达77.36%。研究表明,地形复杂度等地形因子可用于岩性分类,采用因子分析方法可获取反映地形地貌宏观、微观特征的定量指标,且岩性分类效果良好。  相似文献   

湍流度随高度的变化及其对城市宏观地形的依赖     

李大全  孙武  欧阳睿康  黄盛  高梦媛  李庆祥  黄启明 《热带地理》2019,39(3):365-376

分别构建广州主建成区垂直比例尺为1﹕2 000、1﹕1 000和1﹕500的3个建筑物模型，利用大型边界层风洞，在西北和东南两风向下，基于中性流模拟分析了复杂城市地形下湍流度随高度的变化及其对宏观地形的依赖。结果表明：风廓线指数α与不同高度的湍流度之间的关系密切，利用现有模型，根据4类粗糙度边界层和不同垂直比例尺，可确定相应的湍流度随高度变化模型的主要系数，预测精度高。城市地形下最大湍流度面发育在0~0.2 h之间狭窄的范围内。用湍流度形态指数β来表征湍流度随高度的变化，无论城市屋脊还是平坦地形，随着风程区的延伸，廓线的指数α升高，湍流度形态指数β降低。表明同一高度湍流度值具有由迎风区、丘顶区向背风区增高，沿风程逐渐增大的规律，对地形部位和风程的依赖性强，与来流翻越简单地形时的特征一致。  相似文献   

An Amended Chemical Mass Balance Model for Source Apportionment of PM2.5 in Typical Chinese Eastern Coastal Cities     

Qiaoli Wang  Nana Cheng  Sujing Li  Minli Dong  Xiangqian Wang  Linlin Ge  Tianjiao Guo  Wei Li  Xiang Gao 《洁净——土壤、空气、水》2019,47(2)

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城镇增长下的收缩：以武汉为例     

高喆  尹宁玮  童馨仪  李东欣  顾江 《热带地理》2019,39(1):29-36

首先从人口、经济、用地3个维度综合考察武汉市增长与收缩的全貌，并采用县区及街道2个尺度的数据定量描述了武汉市增长与收缩的特征与空间格局，发现武汉市下辖青山区、硚口区、汉阳区和蔡甸区存在局部较严重的收缩现象，空间上形成集聚，形态上呈“穿孔式”。进一步以青山区为案例，着重从资本视角探讨发生局部收缩的内在机制，发现其存在老龄化、少子化趋势，但局部收缩的主因是资本从产业部门的“逃逸”。  相似文献   

13世纪以来中国海洋盐业动态演变及驱动因素     

鲍俊林  高抒 《地理科学》2019,39(4):596-605

海洋盐业是中国海洋经济的重要部分,也是沿海传统产业之一,13世纪以来不断发展演变。将沿海分为北、东、南3个地带,搜集整理与海盐经济相关的多种历史文献及方志资料,运用地理学方法分析评估了海洋盐业百年尺度的动态演化过程,并比较了资源环境与管理政策的驱动作用及其差异。研究表明：① 沿海盐业表现为传统煎法长期主导、逐步废煎改晒的过程,不同盐区的演化进程存在显著差异,北部盐区最快,东部次之,南部整体发展缓慢;② 海盐生产重心长期位于东部的两淮盐区,19世纪后期向北部盐区快速迁移;③ 资源环境与生态差异促进了各岸段海盐生产演化分异,垄断性管理政策迟滞了海洋盐业的空间集聚进程,未来沿海开发与海洋盐业的可持续发展将主要依靠基于资源生态约束的管理政策与技术。  相似文献   

Numerical Simulation on Flow Past Two Side-by-Side Inclined Circular Cylinders at Low Reynolds Number     

Liu  Cai  Gao  Yang-yang  Qu  Xin-chen  Wang  Bin  Zhang  Bao-feng 《中国海洋工程》2019,33(3):344-355

A series of three-dimensional numerical simulations is carried out to investigate the effect of inclined angle on flow behavior behind two side-by-side inclined cylinders at low Reynolds number Re=100 and small spacing ratio T/D=1.5 (T is the center-to-center distance between two side-by-side cylinders, D is the diameter of cylinder). The instantaneous and time-averaged flow fields, force coefficients and Strouhal numbers are analyzed. Special attention is focused on the axial flow characteristics with variation of the inclined angle. The results show that the inclined angle has a significant effect on the gap flow behaviors behind two inclined cylinders. The vortex shedding behind two cylinders is suppressed with the increase of the inclined angle as well as the flip-flop gap flow. Moreover, the mean drag coefficient, root-mean-square lift coefficient and Strouhal numbers decrease monotonously with the increase of the inclined angle, which follows the independent principle at small inclined angles.

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鄂尔多斯盆地北部东胜地区侏罗系—白垩系钻孔数据库与三维地质模型          下载免费PDF全文

张天福  张云  程先钰  孙立新  程银行  周小希  王少轶  马海林  鲁超 《中国地质》2020,47(S1):220-230

随着砂岩型铀矿找矿工作的进一步开展，其对以往钻孔资料集成应用的需求尤为迫切。在煤田钻孔资料“二次开发利用”和“煤铀兼探”新方法、新思路的指导下，通过采集东胜地区钻孔资料属性数据，按照统一的标准和要求，将煤田、铀矿等类型的重要钻孔资料，通过整理、扫描、数据类型转换、录入和集成，建成了东胜地区侏罗系—白垩系综合钻孔数据库，实现了对多源钻孔数据的统一管理。该数据库共包含3个Access数据库和相应的成果图件。每个Access数据库均包含钻孔基本信息表、综合柱状分层表、岩性描述分层表、地层名称及代号表、地层颜色表、测井曲线数据表、测井曲线配置表和钻孔弯曲度测量数据表等8张数据表，分别详细记录了地质编录岩性信息、地层分层信息、岩石颜色信息、测井曲线信息、水文分层信息、钻孔样品采样信息、弯曲度测量信息等。通过应用实践，该钻孔数据库成果可实现连井剖面、含煤含铀目的层的顶底板标高、地层等厚图、砂体等厚图及含砂率图等重要基础地质图件的快速生成，从而提高数据的使用效率并为铀矿勘查及研究工作提供重要数据基础。  相似文献