基于热追踪方法的河流横断面潜流交换时空非均质特征研究  

TEMPORAL SPATIAL PATTERNS OF HYPORHEIC EXCHANGE ALONG A RIVER TRANSECT OF DAWEN RIVER THROUGH THE HEAT TRACING METHOD

作　　者：鲁程鹏[1,2] 张颖 朱静思[1] 王冠[1] 何晓宇[2] 张亚龙[2] 何佳煜 沈红霞[1] 

机构地区：[1]河海大学水文水资源学院,南京210098 [2]河海大学力学与材料学院,南京210098 [3]江苏省水利工程规划办公室,南京210029

出　　处：《第四纪研究》2014年第5期1094-1105,共12页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:41201029);高等学校博士学科点专项科研基金项目(批准号:20120094120019);中国博士后科学基金面上项目(批准号:2013M540410);河海大学国家级大学生创新训练项目(批准号:201410294004)共同资助

摘　　要：本文选取山东省济宁市汶上境内大汶河段作为试验场地,主要对河流横断面浅层河床温度进行现场实时监测,分析河床温度剖面的空间分布和动态特征。采用热追踪方法(热量运移解析模型)求解潜流通量,定量描述潜流交换过程的空间非均质特征和动态特征。温度监测结果表明河床温度空间分布不均匀并呈显著动态变化,受到河水温度波动和河床深处某稳定热源的影响;河床浅层温度变幅大于河床深层,河床温度信号向下传递过程中具有明显的振幅衰减和相位延迟,不同测管处衰减程度存在差异。潜流通量大小随深度变化呈现了多种类型共存的特征,在监测期内,呈现出比单调增长的河水水位更加复杂的变化特征,具有显著的空间异质性。与前人研究结论相比,本次研究证实了潜流通量的时空非均质特征受到了河床地形和河水水位的影响,更加强调了区域地下水温度场与潜流交换的空间分布之间的对应关系。Significant spatial and temporal variability of water fluxes may exist at the hyporheic zone in river channels,and our understanding of complicated flow systems along an entire river transect has been limited to reach-averaged parameters or a small number of discrete point measurements.Temperature measurements with high spatial and temporal resolution were used to identify the hyporheic exchange flux along a river transect.The study site is located at Dawen River between Pipashan Dam and Daicun Dam,about 2km downstream from Pipashan Dam.Distributed temperature sensors were installed at the water body,in the streambed and in the air for a 64 hours temperature monitoring from 11/06 16：00 to 11/09 08：00.A transect of 16 vertical thermal arrays,spaced from 1m to 4m apart laterally across the river,recorded temperature in the streambed.Grain-size analyses of the 20 samples of the streambed sediments collected randomly along the cross section were performed by State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering （Nanjing,China）.The medium sand and coarse sand were recognized from our sediment samples.The one-dimension conduction-advection-dispersion model was used to recognize the temporalspatial pattern of vertical hyporheic flux.The results included three aspects as following：（1） Taken T11 as an example,river water temperatures varied diurnally,reaching a minimum value of 11.50℃ and a maximum of 15.82℃.Meanwhile,the minimum and maximum values of the air temperature were 3.54℃ and 23.03℃.The temperature of the river water is significantly damped from the air temperature due to the great difference of heat capacity between air and water.（2） The streambed has a diurnal temperature oscillation at depths less than 120cm.The profiles T8,T9,T10,T11 and T12 located around the deep grooves had a more pronounced propagation of the diurnal signal and greater transport of heat to depth.The highest temperature occurs at the right bottom of the streambed profile because of steady he

关 键 词：潜流交换 热追踪 空间变异性 动态变化 河床地形 地下水温度 

分 类 号：P641[天文地球—地质矿产勘探]