Long‐term hydrologic simulation using SCS‐CN‐based improved soil moisture accounting procedure     

Dilip G. Durbude  Manoj K. Jain  Surendra K. Mishra 《水文研究》2011,25(4):561-579

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Water quality monitoring at a virtual watershed monitoring station using a modified deep extreme learning machine     

Jian Jin  Lei Li  Huan Xu  Guang Lin 《水文科学杂志》2020,65(3):415-426

ABSTRACT

A new deep extreme learning machine (ELM) model is developed to predict water temperature and conductivity at a virtual monitoring station. Based on previous research, a modified ELM auto-encoder is developed to extract more robust invariance among the water quality data. A weighted ELM that takes seasonal variation as the basis of weighting is used to predict the actual value of water quality parameters at sites which only have historical data and no longer generate new data. The performance of the proposed model is validated against the monthly data from eight monitoring stations on the Zengwen River, Taiwan (2002–2017). Based on root mean square error, mean absolute error, mean absolute percentage error and correlation coefficient, the experimental results show that the new model is better than the other classical spatial interpolation methods.  相似文献   

Monitoring and modelling of hydrological processes in the semiarid region of Brazil: The Cariri experimental basins     

Vajapeyam S. Srinivasan  Hugo M. de Alcântara  Carlos de O. Galvão  Ulisses A. Bezerra  John E. de Brito Leite Cunha 《水文研究》2021,35(5):e14194

Catchments have highly variable yields of runoff and soil erosion. The size, land use and the surface cover play a significant role and influence the catchment response and parameter values of simulation models. Two experimental basins—the Cariri basins—were equipped in a semi-arid region of Brazil, for obtaining runoff and sediment yield at different catchment scales, as well as, to evaluate the influence of the land use and surface cover. In the first basin, located in the municipality of Sumé, the field studies were carried out at two different scales: four micro-catchments with an area of around 0.5 ha and nine standard Wischmeier-type erosion plots of 100 m². The experimental units had varied vegetation and management. They were subjected only to natural rainfall events, and were monitored from 1982 to 1991. The total runoff and total sediment yield were determined for each of the events. The installations in the second basin, in the municipality of São João do Cariri, from 1999, include two erosion plots, three micro-catchments, and two sub-catchments of a small basin. These basins are still being monitored for runoff and sediment production. Among the micro-catchments two are nested to detect any scale effect at the micro-catchment level. Nearly 600 events of precipitation, that produced runoff in at least one of the experimental units, have been registered. These data have been used to evaluate the influence of various factors, including cultivation practices and to calibrate hydrological models for plots and micro-catchments. Parameters have been tested by means of cross validations among micro-catchments and sub-catchments. The data sets are made available to all the catchment hydrology researchers and others at https://doi.org/10.5281/zenodo.4690886 .  相似文献   

Changes in dissolved organic matter (DOM) amount and composition along nested headwater stream locations during baseflow and stormflow          下载免费PDF全文

Shatrughan Singh  Shreeram Inamdar  Myron Mitchell 《水文研究》2015,29(6):1505-1520

Amount and composition of dissolved organic matter (DOM) were evaluated for multiple, nested stream locations in a forested watershed to investigate the role of hydrologic flow paths, wetlands and drainage scale. Sampling was performed over a 4‐year period (2008–2011) for five locations with drainage areas of 0.62, 3.5, 4.5, 12 and 79 ha. Hydrologic flow paths were characterized using an end‐member mixing model. DOM composition was determined using a suite of spectrofluorometric indices and a site‐specific parallel factor analysis model. Dissolved organic carbon (DOC), humic‐like DOM and fluorescence index were most sensitive to changes with drainage scale, whereas dissolved organic nitrogen, specific UV absorbance, Sr and protein‐like DOM were least sensitive. DOM concentrations and humic‐like DOM constituents were highest during both baseflow and stormflow for a 3.5‐ha catchment with a wetland near the catchment outlet. Whereas storm‐event concentrations of DOC and humic DOM constituents declined, the mass exports of DOC increased with increasing catchment scale. A pronounced dilution in storm‐event DOC concentration was observed at peak stream discharge for the 12‐ha drainage location, which was not as apparent at the 79‐ha scale, suggesting key differences in supply and transport of DOM. Our observations indicate that hydrologic flow paths, especially during storms, and the location and extent of wetlands in the catchment are key determinants of DOM concentration and composition. This study furthers our understanding of changes in DOM with drainage scale and the controls on DOM in headwater, forested catchments. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Understanding the relative impacts of natural processes and human activities on the hydrology of the Central Rift Valley lakes,East Africa          下载免费PDF全文

Wondwosen M. Seyoum  Adam M. Milewski  Michael C. Durham 《水文研究》2015,29(19):4312-4324

Significant changes have been observed in the hydrology of Central Rift Valley (CRV) lakes in Ethiopia, East Africa as a result of both natural processes and human activities during the past three decades. This study applied an integrated approach (remote sensing, hydrologic modelling, and statistical analysis) to understand the relative effects of natural processes and human activities over a sparsely gauged CRV basin. Lake storage estimates were calculated from a hydrologic model constructed without inputs from human impacts such as water abstraction and compared with satellite‐based (observed) lake storage measurements to characterize the magnitude of human‐induced impacts. A non‐parametric Mann–Kendall test was used to detect the presence of climatic trends (e.g. a decreasing or increasing trends in precipitation), while the Standard Precipitation Index (SPI) analysis was used to assess the long‐term, inter‐annual climate variability within the basin. Results indicate human activities (e.g. abstraction) significantly contributed to the changes in the hydrology of the lakes, while no statistically significant climatic trend was seen in the basin, however inter‐annual natural climate variability, extreme dryness, and prolonged drought has negatively affected the lakes. The relative contributions of natural and human‐induced impacts on the lakes were quantified and evaluated by comparing hydrographs of the CRV lakes. Lake Abiyata has lost ~6.5 m in total lake height between 1985 and 2006, 70% (~4.5 m) of the loss has been attributed to human‐induced causes, whereas the remaining 30% is related to natural climate variability. The relative impact analysis utilized in this study could potentially be used to better plan and create effective water‐management practices in the basin and demonstrates the utility of this integrated methodology for similar studies assessing the relative natural and human‐induced impacts on lakes in data sparse areas. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Use of a watershed hydrologic model to estimate interbasin groundwater flow in a Costa Rican rainforest          下载免费PDF全文

Carlo Zanon  David P. Genereux  Steven F. Oberbauer 《水文研究》2014,28(10):3670-3680

The watershed hydrologic model TOPMODEL was used to estimate interbasin groundwater flow (IGF) into a small lowland rainforest watershed in Costa Rica. IGF is a common hydrological process but often difficult to quantify. Four‐year simulations (2006–2009) using three different model approaches gave estimates of IGF that were very similar to each other (10.1, 10.2, and 9.8 m/year) and to an earlier estimate (10.0 m/year) based on 1998–2002 data from a budget study that did not use a hydrologic simulation model, providing confidence in the new estimates and suggesting each of the three model approaches is viable. Results show no significant temporal variation in IGF during 2006–2009 (or between this period and the earlier study from 1998–2002). Simulations of the 16 consecutive 3‐month periods in 2006–2009 gave 16 values of IGF rate with a mean (10.1 m/year, standard deviation = 0.6 m/year) very similar to the estimates above from the 4‐year simulations. This suggests the modified version of TOPMODEL can be used to model stream discharge and estimate IGF for sub‐annual time periods during which change in water storage is not necessarily equal to zero. Thus, simple watershed models may be used to estimate IGF based on even relatively short calibration periods, making such models useful tools in the study of this widespread hydrological process that affects water and chemical fluxes and budgets but is often difficult and costly to quantify. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

海洋效应对中国沿海地磁观测影响——以广州台站为例   总被引：2，自引：1，他引：1       下载免费PDF全文

李建平  翁爱华  李世文  杨悦  唐裕  张艳辉 《地球物理学报》2018,61(2):649-658

以广州台站为例，研究海洋效应对中国沿海地磁观测C-响应的影响.海洋效应的三维正演模拟采用球坐标系下交错网格有限差分方法，假设磁层环形电流源，正演电阻率结构模型采用"地表3-D电导+1-D层状背景"复合模型.数值模拟结果表明，中国地区沿海C-响应受海洋效应影响明显.在空间上，沿海岸线方向，受海洋效应影响，单周期的C-响应由无海洋效应的常值变形为平行于海岸线的等值线密集梯度带；在垂直海岸方向，海洋效应影响向内陆减小，其影响可达哈尔滨-贵阳一线.海洋效应影响采用比值法进行校正，以广州台站为例，在比值曲线上发现海洋效应对C-响应的影响最大周期可达20天左右，并且就中国沿海而言，相对全球平均一维模型，利用中国地区平均一维电导率模型作为背景模型的海洋效应校正结果更加合理.进一步对广州台站海洋效应校正前后的C-响应进行了1-D反演，由于校正前的C-响应在小周期时受海洋效应特别大，直接反演无法拟合数据；但校正后反演拟合明显变好，得到的1-D导电模型表明广州地区上地幔及地幔转换带的电阻率比中国平均电阻率高约一个量级，推测中国华南地区南部的地幔转换带可能处于相对冷的环境，该模型可能成为菲律宾海板块西向俯冲并滞留到华南大陆下方地幔转换带的电性证据.  相似文献   

“房桥合一”铁路客站抗震计算的快速高效多维虚拟激励法          下载免费PDF全文

徐汉勇  余志武 《地震工程学报》2018,40(3):438-443

针对"房桥合一"铁路客站节点数多、空间相互作用显著等特点,利用沿结构整体坐标系方向功率谱的表达式和合理谱强度因子的确定方法,提出能合理考虑地震激励输入角度变化的快速多维虚拟激励法,并以天津西站Ⅱ区作为工程案例,对利用快速多维虚拟激励法、时程响应分析法和已有虚拟激励法的计算结果进行比较。结果表明:三种算法的计算结果吻合较好,证明快速多维虚拟激励法的计算值是合理的;且与已有虚拟激励法相比、快速多维虚拟激励法的计算效率显著提高,更适合于"房桥合一"铁路客站的抗震计算。  相似文献   

高精度温度计在水温观测中的仪器稳定性分析     

邱永平 《中国地震》2018,34(4):828-836

利用宁波地震台水温10年来的单测项、6年来的同层比测资料,对高精度温度计的仪器短期和长期稳定性进行分析对比。研究发现仪器长期存在漂移现象,漂移量的大小与每套仪器的系统特性有关,但随着观测时间的延续,漂移量逐渐减少,认为该现象对地震前兆观测影响不大;短期稳定性存在不明原因的阶跃和脉冲现象,但次数不多,幅度不大,如果不是并行观测,较难判别。因此,在资料分析时要考虑仪器的这些问题。有时仪器短期非常稳定,数天至20天整点值为同一测值。  相似文献   

新疆数字化地震台网业务运行管理系统     

陈向军  魏斌 《地震地磁观测与研究》2018,39(3):189-196

新疆数字化地震台网业务运行管理系统具有对地震台站业务考评、网络及设备信息、台站参数、系统运维、数据共享、大震速报、速报编目数据统计和台网资料等信息管理功能。该系统在Windows 7系统环境下，使用MyEclipse平台和MySQL数据库通过JSP技术开发动态Web Service系统，使用Delphi XE10环境开发移动APP。在新疆地震台网投入运行后，解决了日常业务中台站与台站、台网与台站数据和信息交换困难的问题，有效提高了新疆地震台网的运行质量监管力度，方便用户使用各类数据，有较好的推广应用价值。  相似文献