A two-layer model for studying 2D dissolved pollutant runoff over impermeable surfaces     

Taotao Zhang  Yang Xiao  Dongfang Liang  Hongwu Tang  Junzeng Xu  Saiyu Yuan  Nairu Wang  Bin Luan 《水文研究》2021,35(5):e14152

Dissolved pollutants in stormwater are a main contributor to water pollution in urban environments. However, many existing transport models are semi-empirical and only consider one-dimensional flows, which limit their predictive capacity. Combining the shallow water and the advection–diffusion equations, a two-dimensional physically based model is developed for dissolved pollutant transport by adopting the concept of a ‘control layer’. A series of laboratory experiments has been conducted to validate the proposed model, taking into account the effects of buildings and intermittent rainfalls. The predictions are found to be in good agreement with experimental observations, which supports the assumption that the depth of the control layer is constant. Based on the validated model, a parametric study is conducted, focusing on the characteristics of the pollutant distribution and transport rate over the depth. The hyetograph, including the intensity, duration and intermittency, of rainfall event has a significant influence on the pollutant transport rates. The depth of the control layer, rainfall intensity, surface roughness and area length are dominant factors that affect the dissolved pollutant transport. Finally, several perspectives of the new pollutant transport model are discussed. This study contributes to an in-depth understanding of the dissolved pollutant transport processes on impermeable surfaces and urban stormwater management.  相似文献   

Characterizing spatial and temporal variation in 18O and 2H content of New Zealand river water for better understanding of hydrologic processes     

Jing Yang  Bruce D. Dudley  Kelsey Montgomery  Will Hodgetts 《水文研究》2020,34(26):5474-5488

Time series of hydrogen and oxygen stable isotope ratios (δ²H and δ¹⁸O) in rivers can be used to quantify groundwater contributions to streamflow, and timescales of catchment storage. However, these isotope hydrology techniques rely on distinct spatial or temporal patterns of δ²H and δ¹⁸O within the hydrologic cycle. In New Zealand, lack of understanding of spatial and temporal patterns of δ²H and δ¹⁸O of river water hinders development of regional and national-scale hydrological models. We measured δ²H and δ¹⁸O monthly, together with river flow rates at 58 locations across New Zealand over a two-year period. Results show: (a) general patterns of decreasing δ²H and δ¹⁸O with increasing latitude were altered by New Zealand's major mountain ranges; δ²H and δ¹⁸O were distinctly lower in rivers fed from higher elevation catchments, and in eastern rain-shadow areas of both islands; (b) river water δ²H and δ¹⁸O values were partly controlled by local catchment characteristics (catchment slope, PET, catchment elevation, and upstream lake area) that influence evaporation processes; (c) regional differences in evaporation caused the slope of the river water line (i.e., the relationship between δ²H and δ¹⁸O in river water) for the (warmer) North Island to be lower than that of the (cooler, mountain-dominated) South Island; (d) δ²H seasonal offsets (i.e., the difference between seasonal peak and mean values) for individual sites ranged from 0.50‰ to 5.07‰. Peak values of δ¹⁸O and δ²H were in late summer, but values peaked 1 month later at the South Island sites, likely due to greater snow-melt contributions to streamflow. Strong spatial differences in river water δ²H and δ¹⁸O caused by orographic rainfall effects and evaporation may inform studies of water mixing across landscapes. Generally distinct seasonal isotope cycles, despite the large catchment sizes of rivers studied, are encouraging for transit time analysis applications.  相似文献   

中学地理科学实验的六大类型及其案例分析     

杨崝源  段玉山  姚泽阳  马倩怡  刘妍君 《地理教学》2020,(3):9-15

依据实验的根本目的,为拓展学生对地理过程的理解,体验真实的地理原理,笔者将中学地理科学实验划分为经典实验室实验、时间变化模型实验、类比实验、空间变化模型实验、物理模型实验以及计算机模型实验六大类型,并对每一类型实验进行举例分析,希望以此深化地理科学实验的理论研究、丰富地理科学实验的实践案例、培养学生的地理核心素养,为地理科学实验教学研究提供新的视角。  相似文献   

地理试题透视六大解题思维——以浙江省选考试题为例     

杨明 《地理教学》2020,(1):52-55,39

思维是指人脑借助于语言对客观事物的概括和间接反应的过程,以感知为基础,又超越感知的界限,它探索与发现事物的内部本质联系和规律性,是认识过程的高级阶段。目前国内针对地理解题的思维研究相对较少,本文以浙江省历年选考地理试题为例,总结和提炼出六大解题思维,即:逆向思维、收支平衡思维、比较思维、发散思维、空间思维、辩证思维,旨在帮助学生掌握分析和解答地理问题的方法,从而有效提升高中地理学习和复习效果,增强学生学习地理的兴趣。同时在培养学生的地理解题思维过程中,落实地理学科核心素养的培育。  相似文献   

祁连山MODIS LST时空变化特征及影响因素分析          下载免费PDF全文

邱丽莎  何毅  张立峰  王文辉  唐源蔚 《干旱区地理》2020,43(3):726-737

地表温度(Land Surface Temperature，LST)是研究区域尺度和全球尺度上地表能量和水平衡物理过程中不可缺少的参数。祁连山LST的时空变化规律及其影响因素模式未知。通过采用趋势分析法和相关性分析法，探讨2000—2017年间祁连山LST〖WTBZ〗的时空变化特征及与植被的相互关系，分析各植被类型下地表温度的时空分异特征。结果表明：（1） MODIS LST产品的精度能够满足祁连山地表温度时空变化分析的要求。（2） 祁连山LST时间序列呈 “上升—下降—上升—下降”的波动变化，整体呈小幅上升趋势，以0.17 ℃·（10 a）^-1的速率波动上升，冬季LST上升趋势最显著（63.37%），变化率为0.22℃·（10 a）^-1；空间上呈西北降低东南升高的变化趋势，显著上升面积（14.89%）远大于下降面积（0.90%）。（3） 祁连山年均LST与NDVI呈负相关，显著相关区域占22.56%，夏季NDVI对LST的调控作用较显著（25.45%）；荒漠NDVI对LST的影响大于其他植被类型。（4） 海拔对各植被类型LST有强烈的影响，相关性依次为荒漠>林地>草甸>耕地；然而，夏季LST与海拔的相关性因植被覆盖增加而显著降低。（5）祁连山LST上升是NDVI、海拔以及植被类型综合影响的结果。  相似文献   

科尔沁湿草甸参考作物蒸散发模拟分析     

李霞  刘廷玺  段利民  王冠丽  童新  周亚军  杨晓君 《中国沙漠》2020,40(2):134-143

为探明气候变化下干旱半干旱地区湿草甸参考作物蒸散发(ET₀)影响因子,使用FAO 56 P-M模型对科尔沁湿草甸ET₀进行模拟,利用涡度相关系统对模型的适用性进行评价,并通过通径分析及指标敏感性分析对ET₀的影响因子进行辨识。结果表明:(1)小时尺度模拟精度最高,日尺度次之,月尺度较差,小时尺度上晴、阴、雨3种天气条件下模拟效果不同,晴天最优,阴雨天较差。(2)ET₀年内变化呈单峰曲线状,生长季明显高于非生长季,集中在3—10月,占全年89.79%。生长季典型晴天ET₀逐小时分布特征遵循倒“U”单峰型变化规律。(3)通径分析结果显示,对ET₀的通径系数以及对回归方程估测可靠程度E的总贡献均表现为VPD(饱和水汽压差) > T_min(最低气温) > R_n(冠层表面净辐射)>u₂(2 m高度风速),即VPD为影响ET₀最重要的因子;指标敏感性分析中,在去除VPD后引起的E变化最大,说明ET₀对VPD的变化最为敏感,其次为u₂、T_min和R_n。  相似文献   

东北地区水稻扩张的海拔优势区间分析     

黄莹泽  邱炳文  何玉花  张珂  邹凤丽 《地理科学进展》2020,39(9):1557-1564

及时掌握水稻的时空分布信息,对调整和优化农业生产结构至关重要。论文利用综合考虑植被物候和地表水变化的水稻自动制图方法,结合海拔、地表水体因素开展2001—2017年东北地区水稻分布的时空演变研究。通过889个地面调研点位对水稻分类结果验证,总体精度达90.66%,Kappa系数为0.8128。研究表明:① 21世纪初,东北地区水稻种植面积呈先略减后持续增加的趋势,2017年水稻种植面积达2001年的2.13倍。其中,水稻扩张面积的60%分布在三江平原,30%分布在松嫩平原,下辽河平原仅占不足5%。水稻扩张的海拔优势区间在200 m范围内,随着海拔的上升水稻扩张与地表水关系越来越密切。② 三江平原内,水稻扩张幅度在海拔30~70 m范围内逐渐增加,使优势区间从相对高度70 m缩减至40 m内,也使得分布优势逐渐趋向于距地表水体较远的区域。而松嫩平原和下辽河平原水稻种植分布的海拔优势区间始终分别保持在相对高度100 m、40 m内。③ 三江平原水稻的集中分布和急剧扩张,使水稻分布优势逐渐趋向于距地表水体远的区域,这将对地下水带来更大的压力;而松嫩平原水稻分布受地表水体影响较大,分布优势随着距地表水体距离的增加而减小。研究可为农业部门评估水资源承载力、保障农业可持续发展提供数据支撑及理论参考。  相似文献   

南极罗斯海沉积物中可培养菌株的分离及胞外水解酶活性检测          下载免费PDF全文

王飞  丛柏林  张朝晖  杨黄浩 《极地研究》2020,32(1):68-81

研究了南极罗斯海地区沉积物中可培养微生物多样性,并检测了菌株胞外酶活性,为开发利用南极资源奠定基础。采用Zobell2216E培养基、土豆培养基(PDA)及稀释平板划线法分离并获得纯培养的细菌和真菌,分别通过16SrDNA、18S/ITS序列鉴定分析了可培养微生物的多样性和系统发育。从南极罗斯海沉积物样品中获得78株细菌和54株真菌,细菌、真菌的优势菌株分别为嗜冷杆菌属(Psychrobacter)、枝孢属(Cladosporium);78株细菌菌株中有2株与模式菌株的16SrDNA基因序列相似性小于97%,可能是潜在的细菌新物种。细菌API20NE生理生化和真菌产胞外酶活性结果表明,获得的细菌和真菌大多数可检测到胞外水解酶活性。本研究丰富了南极可培养微生物资源,为南极罗斯海地区可培养微生物的多样性研究以及南极微生物资源的应用研究奠定了基础。  相似文献   

China’s rural revitalization and development: Theory,technology and management     

Liu  Yansui  Zang  Yuzhu  Yang  Yuanyuan 《地理学报(英文版)》2020,30(12):1923-1942

Journal of Geographical Sciences - The urban-rural transformation from dichotomy to integration is a gradual process. Like rural areas in many countries, Chinese rural society is experiencing a...  相似文献   

Identifying primary public transit corridors using multi-source big transit data     

Tong Zhang  Yicong Li  Hui Yang  Chenrong Cui  Jing Li  Qinghua Qiao 《International journal of geographical information science》2020,34(6):1137-1161

ABSTRACT

Effective public transit planning needs to address realistic travel demands, which can be illustrated by corridors across major residential areas and activity centers. It is vital to identify public transit corridors that contain the most significant transit travel demand patterns. We propose a two-stage approach to discover primary public transit corridors at high spatio-temporal resolutions using massive real-world smart card and bus trajectory data, which manifest rich transit demand patterns over space and time. The first stage was to reconstruct chained trips for individual passengers using multi-source massive public transit data. In the second stage, a shared-flow clustering algorithm was developed to identify public transit corridors based on reconstructed individual transit trips. The proposed approach was evaluated using transit data collected in Shenzhen, China. Experimental results demonstrated that the proposed approach is a practical tool for extracting time-varying corridors for many potential applications, such as transit planning and management.  相似文献