• 全国中文核心期刊
  • 中国科技核心期刊
  • 美国工程索引(EI)收录期刊

2015 Vol. 26, No. 3

Display Method:
Spatial and temporal patterns of precipitation variability over mainland China:I: Climatology
REN Guoyu, ZHAN Yunjian, REN Yuyu, CHEN Yu, WANG Tao, LIU Yanju, SUN Xiubao
2015, 26(3): 299-310. doi: 10.14042/j.cnki.32.1309.2015.03.001
Abstract:
Climatological characteristics of precipitation in mainland China are analysed by using an updated daily precipitation dataset from 2 300 stations for period 1956—2013. The new findings are as follows: ① The largest precipitation amount, days and intensity of rainstorms concentrate in the coastal zone of southern China, while the largest precipitation amount and days of light rain are mainly seen in inland mountains and hills south of the Yangtze River; in the eastern summer monsoon region, the highly intensive rain generally occurs in the low-laying plains and coastal zones, and the light rain mostly in the mountains and hills. ② Precipitation of all the seasons decreases from southeast to northwest; precipitation of autumn is much less than that of spring in southern China, but the autumn precipitation is more abundant in the Qinling Mountains, the Daba Mountains and the Sichuan Basin, and along the narrow coastal zone; the largest winter precipitation occurs in the hills region of south-eastern China. ③ Double to triple peaks of precipitation in a year appear in the Pear River basin, the south-eastern rivers and the mid-to lower Yangtze River basin, with the main peak in mid-to late June and secondary one in late August for the south-eastern rivers, for example, and main peak in June and secondary one in mid-August for the Pear River basin; all the northern rivers witness a single peak in late July. ④ The southern large rivers enter into rainy season gradually from late February to mid-to late June, and the northern large rivers enter into rainy season almost simultaneously in late June and early July; the close dates of rainy season are much concentrated across the eastern China, with the beginning time lasting for more than 120 d from the south to the north, and the closing time from the north to the south only lasting for less than 45 d. ⑤ The beginning and closing dates of potential flood season occur in the early May and the early September in the Pear River basin, the early May and the early July and then the late August and the beginning of September for second time in the south-eastern large river basins, the mid-to late June and the mid-July in the Yangtze River basin, the mid-July and the late August in the south-western large river basins, and the early July and the beginning of August in the Huaihe River basin; a very short potential flood season appears between the end of July and the beginning August in the Liaohe River basin, and no such a period can be found for the other northern large rivers. ⑥ The largest variability coefficients of annual and seasonal precipitation are found in the southwestern Tibetan Plateau, the Talimu Basin, the Alashan Plateau, northern part of the North China Plain and the Fenhe River basin of eastern Loess Plateau; the vast region south of the Yangtze River witnesses smaller inter-annual variability; the Haihe River basin registers the largest basin-averaged variability coefficients of annual precipitation in all of the ten large river basins of mainland China.
Calculation methods for sediment load and deposition volume in the Inner Mongolia reach of the Yellow River
WU Baosheng, LIU Kejing, SHEN Hongbin, ZHOU Liyan
2015, 26(3): 311-321. doi: 10.14042/j.cnki.32.1309.2015.03.002
Abstract:
Based on the basic sediment transport equation that reflects the characteristics of "more input, more output" for sediment-laden flow rivers, a general sediment transport expression was developed, which can take into account the effects of upstream sediment input, previous cumulative sediment deposition, critical water volume for sediment initiation, and sediment sizes of mainstem and tributary. Then annual sediment load equations for the whole Inner Mongolia reach from Bayangaole to Toudaoguai and for the sub-reaches from Bayangaole to Sanhuhekou and from Sanhuhekou to Toudaoguai were obtained based on measured data for the Inner Mongolia reach of the Yellow River from 1953 to 2010. And then annual deposition volumes at each river reach were calculated using the proposed equations for years from 1953 to 2010 according to the principle of sediment conservation. Analysis of results for the selected river reach from Sanhuhekou to Toudaoguai shown that the determination coefficient R2 between measured and calculated annual amount of erosion and sedimentation was raised from 0.41 for using the basic transport equation to 0.50, 0.75 and 0.80, respectively, by successively adding the parameters of upstream sediment input, previous cumulative sediment deposition, critical water volume for sediment initiation, and sediment sizes of mainstem and tributary. This indicated the necessity of including these parameters at top of the basic transport equation. In addition, annual deposition and cumulative deposition volumes calculated using the proposed sediment transport load equations for the whole reach and the sun-reaches were in good agreement with measurements. This indicated that the proposed methods can be used for calculation of annual sediment load and deposition volume under different flow and sediment load conditions and for analysis of sediment transport and long-term trend of sediment deposition in the Inner Mongolia reach of the Yellow River.
A fully coupled numerical simulation for surface runoff and soil water movement
ZHU Lei, TIAN Juncang, SUN Xiaolei
2015, 26(3): 322-330. doi: 10.14042/j.cnki.32.1309.2015.03.003
Abstract:
Aiming at this dynamic process that the infiltration will be occurred when the rainfall runoff flows down from a slope surface and the caused increase of soil water content in an unsaturated zone, the soil water and surface water were coupled from the physical mechanism in this paper. A two-dimensional plane model of the surface water was superimposed on top of a soil water model, and the same spatial and temporal discretizations were maintained for both models. In addition, during the calculation process for the models, the water exchange between the surface and soil water was calculated (double node analysis coupling) or a global approach integrating the discretization equation was coupled. Comparing the two coupling methods and compared with previously published experimental results, the model and coupling method in this paper can be used to accurately simulate and predict the movement processes of surface runoff and soil water. The research results of this paper can provide theoretical support to analyze surface water flow and the coupling mechanism of the water content and solute between saturated and unsaturated zones.
Rules of the dynamic water-heat-salt transfer in soil of Horqin meadow during freezing and thawing period
LIU Xiaoyan, LIU Qiaoling, LIU Tingxi, DUAN Limin, YUE Cuitong
2015, 26(3): 331-339. doi: 10.14042/j.cnki.32.1309.2015.03.004
Abstract:
To elucidate the dynamic water-heat-salt transfer in soil during freezing and thawing periods, data on weather and soil in Horqin meadow were analyzed and changes in the temperature, water content, and salt content of the soil in the meadow during these periods were investigated. Data were collected by the Agoura Eco-hydrological Experiment station at Zuoyihouqi, Horqin from October 2013 to May 2014. Results indicated that the effect of temperature on the soil profile temperature decreased with increasing soil depth. In addition, changes in soil profile temperature lagged behind temperature variations and were also affected by the amplitude of temperature variation. Moreover, these changes showed no significant pattern. When the rate of temperature increase exceeded that the rate of cooling, the rate of soil thawing consequently increased compared with that the rate of freezing. Freezing begins from the soil surface and proceeds deeper beneath the surface, and freezing temperature was negatively correlated with the salt content of the soil. Linear interpolation of the temperature was adopted to accurately determine the maximum frost depth in the meadow on 9 March 2014. The computed maximum frost depth was 104 cm. Because of the effects of underground heat from warm soil and surface temperature, the thawing begins from two directions, namely, bottom-to-surface and surface-to-bottom. The groundwater depth is shallow and is affected by soil freezing and thawing with significant ascending or descending trend. During the soil freezing period, soil salt accumulates on the surface and reaches the maximum content in February. Salt content decreases after thawing and rain. During the freezing and thawing periods, the soil's salt content shows greater changes than soil's water content, thereby indicating that the salt transfer process is complicated.
A study of substitutability of TRMM remote sensing precipitation for gauge-based observation in Ganjiang River basin
TANG Guoqiang, LI Zhe, XUE Xianwu, HU Qingfang, YONG Bin, HONG Yang
2015, 26(3): 340-346. doi: 10.14042/j.cnki.32.1309.2015.03.005
Abstract:
Multi-satellite remote precipitation sensing products provide a new source of data for hydrological simulation in basins with no or little observation. In this study, TRMM precipitation products (3B42V7 and 3B42RTV7) were evaluated quantitatively, and then coupled with CREST a distributed hydrological model to explore whether TRMM satellite precipitation products can substitute ground observations in the Ganjiang River basin, a typical Chinese storm region. Results indicate that 3B42 and 3B42RT fit well with ground observations, with the monthly correlation coefficients exceeding 0.9 and bias less than 5%, while the indices for daily precipitation is slightly worse. Two scenarios were also designed: Scenario I used static parameters in which gauge precipitation was used to calibrate the CREST model and satellite precipitation was used to validate it; Scenario II used dynamic parameters in which the model was recalibrated based on both satellite precipitation products. Comparison shows that the model performs better after recalibration in Scenario II, proving that mainstream satellite precipitation products have the potential to substitute gauged-based observations after model recalibration.
Research on the 10-minute rainfall prediction model for debris flows
YU Bin, ZHU Yuan, WANG Tao, ZHU Yunbo
2015, 26(3): 347-355. doi: 10.14042/j.cnki.32.1309.2015.03.006
Abstract:
High-intensity short duration rainfall was the main triggering factor for the gully type debris flows which are triggered by a runoff induced mechanism. The 10-minute rainfall intensity is considered as the trigger. A revised prediction model with factors related to rainfall is introduced for this kind of gully type debris flows and applied to the Jiangjia gully. A 10-minute rainfall coefficient intensity is proposed based on the 1-hour prediction model, and the observational data of Jiangjia gully is presented. The model was successfully validated in debris flow gullies with the same initiation mechanism in other areas of west China. The generic character of the model is explained by the fact that its factors are partly based on the initiation mechanisms and not only on the statistical analyses of an unique variety of local factors. The research provides a new way to predict the occurrence of debris flows initiated by a runoff induced mechanism.
A real-time probabilistic channel flood forecasting model and application based on particle filters
XU Xingya, FANG Hongwei, ZHANG Yuefeng, LAI Ruixun, HUANG Lei, LIU Xiaobo
2015, 26(3): 356-364. doi: 10.14042/j.cnki.32.1309.2015.03.007
Abstract:
We can improve the accuracy of real-time flood forecasting models using data assimilation, which integrates hydrological observation data with the flood forecasting model. We have developed a real-time, probabilistic channel flood forecasting model based on a particle filter. It takes the discharge, stage, and roughness coefficient of cross sections along the river as the basic particles of the flow state, and stage observations at hydrological stations as the required observations. We applied the model to a real flood event, downstream from the Yellow River. Our results show that particle filter algorithm effectively corrected the flow state particles. Additionally, we produced more accurate intervals for the flow's initial condition and roughness coefficient, which can be used in future flood forecasting calculations. These will improve the accuracy of the model's predictions, because the probabilistic intervals are more appropriate. Moreover, the forecasts for different lead times indicate that, as the lead time increases, the positive effect of the data assimilation weakens, reducing the accuracy of the forecasts. The uncertainties of the stage prediction increase over time, because different particles have different roughness coefficients. Additionally, the uncertainties of the discharge predictions decrease over time, because of the given deterministic model boundary conditions. The model can successfully assimilate the original historical stage observation data, which shows that it is practical and can be applied to real flood forecasting tasks.
Free-water storage error correction based on dynamic system response in flood forecasting
BAO Weimin, QUE Jiajun, LAI Shanzheng, SI Wei
2015, 26(3): 365-371. doi: 10.14042/j.cnki.32.1309.2015.03.008
Abstract:
It has proposed a new method of correcting free-water storage based on dynamic system response in order to improve the real-time flood forecasting accuracy. Taking the part below the free-water reservoir of Xin'anjiang model as a system and connecting the disturbance of free-water storage with the corresponding system response difference, this method, has established an error inversion correction model, tracking back to the error source through the least square method, for free-water storage. It has been verified through the application of ideal model and Dongzhen drainage basin, and compared with the corrected results of AR(2) model. It is indicated that the correction effects of the new method is obviously better than that of the AR(2) model for the 16 floods happened historically to this drainage basin. Therefore, this method could be popularized in practical drainage basins.
Numerical simulation of confluence flow structure between Jialing River and Yangtze River
WANG Xiekang, ZHOU Sufen, YE Long, WANG Haizhou
2015, 26(3): 372-377. doi: 10.14042/j.cnki.32.1309.2015.03.009
Abstract:
Concerning the complexity in flow characteristics and riverbed variations at the confluence region of natural river, a three-dimensional, numerical model of two phase flow is developed to explore the hydrodynamic characteristics of confluence flow between Yangtze River and Jialing River. The investigation focuses on the characteristics of separation zone, shear layer, flow velocity field, and helicity under the complex boundary and topography conditions. The results indicate that the pattern of separation zone is heavily influenced by the topography, tends to shift to the right-side of the river with the increasing of water level, and the shape of shear layer formulates a distorted, curved surface. Upon entering the confluence zone, all original secondary vortexes join together and present the tendency of moving to the right side of the channel; while the strength of the secondary flows tends to weaken on the right bank. In addition, two main helix flows are observed and captured at the confluence zone between Yangtze River and Jialing River.
Formation and development process of inland river delta deposition
LIU Fei, ZHANG Xiaofeng, DENG Anjun
2015, 26(3): 378-387. doi: 10.14042/j.cnki.32.1309.2015.03.010
Abstract:
This paper used the flume generalized experiment to investigate the formation and development of delta deposition, after the water flow and sediment was transport into the shallow water lake from the inland river. The result showed that the delta deposition's formation and development of delta deposition can be divided into three stages on the change of plane configuration. First stage, the formation and development followed small sand wave, banded sand wave, fan delta deposition and tongue morphogenetic development, without main channel on the surface of the deposition and no string ditch on both sides. Second stage, water flow and sediment went along the surface of deposition's channel moved forward on the left and the right side region alternately. The last stage, water flow and sediment went along the new channel synchronous moved forward. In the longitudinal launching, the initial rate was larger and gradually decreasing affected by the lateral broadening. The second stage, delta deposition moved forward as relative stabilization rate alternate propulsion. The third stage, longitudinal launching rate showed a weakening trend, and finally keeped overall synchronized advance rate. In the vertical deposition, the deposition at a state rate silting up development. In the lateral broadening, water flow and sediment transverse sediment transport because of the influence of river channel mainstream swing.
A new exponent profile for the equilibrium suspended sediment
SONG Zhiyao, CHENG Chen
2015, 26(3): 388-395. doi: 10.14042/j.cnki.32.1309.2015.02.016
Abstract:
Based on the diffusion equations of suspended sediment concentration (SSC), we analyzed the inherent irrationality of the free surface condition in some main solutions for the equilibrium profile with different diffusion coefficient expressions, and reconstructed a 1/2 power-law diffusivity expression by geometric mean method according to the distribution characteristics of constant and linear diffusivity profiles, then a new exponent profile was derived for SSC under equilibrium condition in this paper. Through the comparison between the new diffusivity distribution as well as its corresponding SSC profile and a lot of measured data from abundant literatures, together with the study results by van Rijn and Zhang, it is shown that this new exponent profile not only has higher precision in computing SSC, but also is characterized by simple expression, limited bed layer SSC and direct integral which are the distinguished features superior to Rouse equation, van Rijn equation and Zhang equation. Therefore, it is a simple and robust profile for the equilibrium SSC with more superiority in theoretical research and practical applications of hydrology, sedimentology and water resources.
Velocity distribution of nonuniform flow on the stoss side over dunes
MA Dianguang, DONG Weiliang, XU Junfeng
2015, 26(3): 396-403. doi: 10.14042/j.cnki.32.1309.2015.02.017
Abstract:
In order to further reveal the flow characteristics over dunes and thus improve the calculation accuracy of velocity, the time-mean velocity profile was analyzed both experimentally and theoretically, and the instantaneous velocities were measured over two different forms of dunes at a shallow depth by virtue of Acoustic Doppler Velocimeter (ADV). Based on the secondary flow formula proposed by Yue, together with the flow characteristics of dunes, a formula of velocity vertical distribution over dunes, including the functions of development and correction, was put forward on the premise that the secondary flow on the stoss side was a continuous evolution process. The results showed that the effects of dunes on incident flow surface became more significant with the decrease of relative depth of water, which made the upside velocity decrease and near-bed velocity increase. By comparison with flume experimental data, the proposed formula had a good agreement with measured values, which could well describe the velocity profile.
Application of groundwater level data to data assimilation for unsaturated flow
SHI Liangsheng, ZHANG Qiuru, SONG Xuehang, FANG Xudong
2015, 26(3): 404-412. doi: 10.14042/j.cnki.32.1309.2015.03.011
Abstract:
Groundwater level is a low-cost measurement that may contain valuable information about unsaturated flow. To provide an insight into the value of groundwater level data, the ensemble Kalman filter for one-dimensional saturated-unsaturated flow is developed to assimilate the dynamic groundwater level data. The potential value of groundwater level data is investigated in a series of synthetic numerical experiments. Results show that when assimilating the groundwater level data alone, the model parameters and state variables give better estimations of the pressure head distribution when updated simultaneously than when only the state variables are updated. Groundwater level data leads to satisfactory estimations if one of the soil hydraulic parameters in the multi-layer soil is identified. However, groundwater level data cannot produce optimal (unique) estimates if multiple parameters are determined simultaneously because of the complicated relationships between the groundwater level data and other parameters. Groundwater level is a source of supplementary information that, when jointly used with soil water content data, can be used to improve parameter estimations and predictions of soil moisture content.
Improved quantum-behaved particle swarm optimization and its application in optimal operation of hydropower stations
FENG Zhongkai, LIAO Shengli, NIU Wenjing, SHEN Jianjian, CHENG Chuntian, LI Zehong
2015, 26(3): 413-422. doi: 10.14042/j.cnki.32.1309.2015.03.012
Abstract:
This paper develops an improved quantum-behaved particle swarm optimization (IQPSO) to alleviate the existing defects of the quantum-behaved particle swarm optimization, such as premature convergence and poor search ability. Firstly, the chaotic search is employed to promote the quality of initial population. Secondly, the evolution pattern of the population is improved by using the weighted updating the population mean best position. Thirdly, the mutation operator is introduced to ensure the global searching ability. Moreover, according to the peculiarities of the optimization problem, the matrix real-coded particle and the complex constraints handling method are designed to further enhance the search efficiency. The proposed method is applied to the optimal operation in Wujiang River cascade hydropower stations. The results demonstrate the effectiveness and practicality of the proposed method in engineering applications. Compared to the progressive optimality algorithm, the spilling discharge and computation time of IQPSO in long-term simulation are reduced by 8.9% and 72.3%, respectively. IQPSO is an efficient and practical approach for the optimal operation of large-scale hydropower system.
Impact on Dongting Lake channel caused by the change of flow and sediment environment after Three Gorges Project impoundment
ZHANG Ming, FENG Xiaoxiang, LIU Zhe, LI Weijuan
2015, 26(3): 423-431. doi: 10.14042/j.cnki.32.1309.2015.03.013
Abstract:
The change of river-lake relation is one of the most important factors affecting the flow and sediment environment in the Dongting Lake area. This has a great influence on the safety and development of lake shipping. On the basis of the hydrological and topographical field data, this paper studies the variation in the characteristics of the water-silt environment and then analyzes its influence on the lake channel. The following results were observed that after the project impoundment: ① The mean monthly discharge in dry seasons tends to decrease, the siltation in the lake area slows down and even scours, the low water level at the lake outlet rises to a certain extent, the water surface gradient in the lake tends to decrease; ② The decrease of incoming sediment causes the channel incision, and the rise of low water level at the lake outlet increases the channel water level, the channel is therefore deepened. The river-lake relation is overall positive factor for the lake channel and the benefits for the Xiangjiang channel are more than that for the Kaihu channel.
Current status and problems of non-point source pollution load calculation in China
LIU Zhuang, CHAO Jianying, ZHANG Li, XIE Yufeng, ZHUANG Wei, HE Fei
2015, 26(3): 432-442. doi: 10.14042/j.cnki.32.1309.2015.03.014
Abstract:
Calculation of the load of non-point source pollution (NPS) is of considerable significance in the control of total water pollution. In order to analyze the current status and problems of NPS load calculation in China, the authors provide an overview of previous relevant studies, and summarize the methods by which the NPS loads have been calculated that are commonly used in China. These include export coefficient models, empirically based models, and physically based models. The authors also discuss the problem of NPS load calculation in four respects: The definition of NPS, the difference between the amount of NPS generated and the amount discharged, NPS load calculation in plains regions, and the differences in NPS characteristics between North America and China, regard the key factors underlying NPS research is the load calculation models and methods adapted to the characteristic of study area. Finally, some recommendations for these problems are proposed, including strengthening the cooperation in the research fields of empirical studies, theory studies and model developments, and developing models and methods adapted to the environmental characteristics of China.
Conceptual discrimination on the urban water security under the perspective of non-traditional security
CHEN Junting, XU Jiangang, XU Youpeng
2015, 26(3): 443-450. doi: 10.14042/j.cnki.32.1309.2015.03.015
Abstract:
With the ongoing development from the water treatment to water security management, the studies on urban water security have shifted their perspectives from the field of natural science to the field of social humanity. However, both the domestic and overseas studies still remain at a stage of practical exploration and experience sharing, and a complete, distinct conceptual and theoretical system has not been formed yet. To this end, this paper is intended to build its theoretical system that incorporates the studies on urban water security into the scope of non-traditional security. The first step begins with the original meaning of security to discuss the disciplinary affiliation of the urban water security, followed by the interpretation on its subject relationship from the inter-subjectivity and the analysis of the dynamic process of securing urban water from the angle of safe physical and social construction. Also, the general framework built upon the non-traditional security theory is used to destruct the designated objects and their security values related to the urban water security. All contributes to a conclusion of the concept of urban water security, providing a new thinking direction for studies on the urban water security in which both the nature and humanity are taken into account.