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1.
Using a nonstationary flood frequency model, this study investigates the impact of trends on the estimation of flood frequencies and flood magnification factors. Analysis of annual peak streamflow data from 28 hydrological stations across the Pearl River basin, China, shows that: (1) northeast parts of the West and the North River basins are dominated by increasing annual peak streamflow, whereas decreasing trends of annual peak streamflow are prevailing in other regions of the Pearl River basin; (2) trends significantly impact the estimation of flood frequencies. The changing frequency of the same flood magnitude is related to the changing magnitude or significance/insignificance of trends, larger increasing frequency can be detected for stations with significant increasing trends of annual peak streamflow and vice versa, and smaller increasing magnitude for stations with not significant increasing annual peak streamflow, pointing to the critical impact of trends on estimation of flood frequencies; (3) larger‐than‐1 flood magnification factors are observed mainly in the northeast parts of the West River basin and in the North River basin, implying magnifying flood processes in these regions and a higher flood risk in comparison with design flood‐control standards; and (4) changes in hydrological extremes result from the integrated influence of human activities and climate change. Generally, magnifying flood regimes in the northeast Pearl River basin and in the North River basin are mainly the result of intensifying precipitation regime; smaller‐than‐1 flood magnification factors along the mainstream of the West River basin and also in the East River basin are the result of hydrological regulations of water reservoirs. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

2.
Multiscale variability of streamflow changes in the Pearl River basin,China   总被引：1，自引：1，他引：0  
The Pearl River basin bears the heavy responsibility for the water supply for the neighboring cities such as Macau, Hong Kong and others. Therefore, effective water resource management is crucial for sustainable use of water resource. However, good knowledge of changing properties of streamflow changes is the first step into the effective water resource management. With this in mind, stability and variability of streamflow changes in the Pearl River basin is thoroughly analyzed based on monthly streamflow data covering last half century using Mann–Kendall trend test and scanning t- and F-test techniques. The results indicate: (1) significant increasing monthly streamflow is observed mainly in January–April, June and October–December. Monthly streamflow during May–September is in not significant changes. Besides, stations characterized by significant monthly streamflow changes are located in the middle and the lower Pearl River basin; (2) changing points of monthly streamflow series are detected mainly during mid-1960s, early 1970s, mid-1970s, early 1980s and early 1990s and these periods are roughly in good agreement with those of annual, winter and summer precipitation across the Pearl River basin, implying tremendous influences of precipitation changes on streamflow variations; (3) abrupt behaviors tend to be ambiguous from the upper to the lower Pearl River basin, which should be due to enhancing combined effects of abrupt changes of precipitation. The streamflow comes to be lower stability in recent decades. However, high stability of streamflow changes are observed at hydrological stations in the lower Pearl River basin. The results of this study will be of great scientific and practical merits in terms of effective water resource management in the Pearl River basin under the influences of climate changes and human activities.  相似文献   

3.
Based on daily meteorological data at 43 gauging stations in the Pearl River basin and 65 gauging stations in the Yellow River basin, we analyze changing properties of actual evapotranspiration (ETa), reference evapotranspiration (ETref) and precipitation in these two river basins. In our study, Pearl River basin is taken as the ‘energy-limited’ system and the Yellow River basin as the ‘water-limited’ system. The results indicate decreasing ETa in the Pearl River and Yellow River basin. However, different changing properties are detected for ETref when compared to ETa. The middle and upper Yellow River basin are characterized by increasing ETref values, whereas the Pearl River basin is dominated by decreasing ETref values. This result demonstrates enhancing drying force in the Yellow River basin. ETa depends mainly on the changes of precipitation amount in the Yellow River basin. In the Pearl River basin, however, ETa changes are similar to those of ETref, i.e. both are in decreasing trend and which may imply weakening hydrological cycle in the Pearl River basin. Different influencing factors are identified behind the ETa and ETref in the Pearl River and Yellow River basin: In the Pearl River basin, intensifying urbanization and increasing aerosol may contribute much to the evapotranspiration changes. Variations of precipitation amount may largely impact the spatial and temporal patterns of ETa in the Yellow River basin. The current study is practically and scientifically significant for regional assessment of water resource in the arid and humid regions of China under the changing climate.  相似文献   

4.
The East River in the Pearl River basin, China, plays a vital role in the water supply for mega‐cities within and in the vicinity of the Pearl River Delta. Knowledge of statistical variability of streamflow is therefore important for water resources management in the basin. This study analyzed streamflow from four hydrological stations on the East River for a period of 1951–2009, using ensemble empirical mode decomposition (EEMD), continuous wavelet transform (CWT) technique, scanning t and F tests. Results indicated increasing/decreasing streamflow in the East River basin before/after the 1980s. After the early 1970s, the high/low flow components were decreasing/increasing. CWT‐based analysis demonstrates a significant impact of water reservoirs on the periodicity of streamflow. Scanning t and F test indicates that significantly abrupt changes in streamflow are largely influenced by both water reservoirs construction and precipitation changes. Thus, changes of streamflow, which are reflected by variations of trend, periodicity and abrupt change, are due to both water reservoir construction and precipitation changes. Further, the changes of volume of streamflow in the East River are in good agreement with precipitation changes. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

5.
Nonstationary GEV-CDN models considering time as a covariate are built for evaluating the flood risk and failure risk of the major flood-control infrastructure in the Pearl River basin, China. The results indicate: (1) increasing peak flood flow is observed in the mainstream of the West River and North River basins and decreasing peak flood flow is observed in the East River basin; in particular, increasing peak flood flow is detected in the mainstream of the lower Pearl River basin and also in the Pearl River Delta region, the most densely populated region of the Pearl River basin; (2) differences in return periods analysed under stationarity and nonstationarity assumptions are found mainly for floods with return periods longer than 50 years; and (3) the failure risks of flood-control infrastructure based on failure risk analysis are higher under the nonstationarity assumption than under the stationarity assumption. The flood-control infrastructure is at higher risk of flood and failure under the influence of climate change and human activities in the middle and lower parts of Pearl River basin.
EDITOR D. Koutsoyiannis

ASSOCIATE EDITOR G. Thirel  相似文献   

6.
The statistical characteristics of precipitation on the daily resolution play an important role not only in the risk assessment of floods and droughts but also in the land use management. In this study, spatial and temporal patterns of the precipitation concentration in the Yangtze River Basin are investigated by using three indices, i.e. precipitation concentration index (CI), precipitation concentration degree (PCD) and precipitation concentration period (PCP). Based on meteorological data of 147 stations for the period of 1960–2008, non‐parametric trend analysis and wavelet transformation analysis are employed to detect the temporal variation of these indices. Spatial variability of precipitation concentration indices and their trends are analysed and demonstrated with the help of GIS tools. The results indicate the following: (i) The high precipitation CI values mainly distribute in the middle region of the Yangtze River Basin, whereas the lower and lowest CI values are found in the lower and upper regions, respectively. A roughly east–west gradient for PCD value and PCP value varies from 0.26 to 0.77 and from 123 to 197, respectively. (ii) The analysis results of precipitation CI trends for different periods (i.e. recent 40, 30 and 20 years) show that the middle region of the Yangtze River Basin experienced a transition from decreasing precipitation CI to increasing precipitation CI during the last two decades, although the decreasing long‐term trends in the precipitation CI are not significant in most areas during the period of 1960–2008. (iii) The upper basin, middle basin and lower basin are, respectively, dominated by the significant decreasing, increasing and no significant trends in PCD. A dominance of insignificant PCP trends is observed in the entire basin during 1960–2008 despite that a few areas in the upper region are characterized by significant decreasing trends. (iv) Interdecadal oscillations can be found for three precipitation indices, but with no constant periodicity. Furthermore, good positive correlations have been detected between precipitation CI and PCD, whereas insignificant correlation coefficients of PCP with precipitation are common in the basin. The results can provide beneficial reference to water resource and eco‐environment and mitigation to flood or drought hazards in the Yangtze River Basin for policymakers and stakeholders. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

7.
Data on sediment flux at three hydrologic stations from the 1950s to 2006 are utilized to study the decadal,annual,and monthly variations in suspended sediment load delivered from the Pearl River to the ocean.Results show that variations in sediment flux from three main tributaries,including the West River,the North River and the East River,are spatially non-uniform.Since nearly 90%of the suspended sediment load comes from the West River,its variation has dominated the overall tendency of sediment flux in the entire Pearl River.Although a significant decreasing trend exists in the annual variation of the total sediment flux,the decadal change can be divided into an increasing phase and a decreasing phase,with the turning point between the two phases in the late 1980s.From the 1950s to the 1980s,the average annual river sediment flux increased by 30.43%.However,sediment flux has decreased significantly since the 1990s,with the average sediment flux being 38.60%less in the 2000s than that in the 1950s.The current sediment flux is also 52.93%less than its peak in the 1980s. The monthly variation pattern of the suspended sediment load transport to the sea is more interesting. For the West River,all months show a decreasing trend,and for most months the reduction values are significant.However,for the East River the sediment load shows a decrease trend in the dry season and an increase trend in the wet season.The method of regression analysis was used to study the influence of precipitation in the variation on the sediment flux.It was found that the climate change is not the main driving force behind the variation in suspended sediment load.Before the 1990s, intensive land use destroyed the vulnerable ecosystem of the upper Pearl River,and speeded up the process of rocky desertification.Consequently,aggravated soil erosion caused an increase in suspended sediment load.However,sediment retention within reservoirs had begun to play a dominant role after the massive construction of large dams after 1990,and resulted in a decrease in the suspended sediment load delivered to the ocean.  相似文献   

8.
Streamflow series of five hydrological stations were analyzed with aim to indicate variability of water resources in the Tarim River basin. Besides, impacts of climate changes on water resources were investigated by analyzing daily precipitation and temperature data of 23 meteorological stations covering 1960–2005. Some interesting and important results were obtained: (1) the study region is characterized by increasing temperature, however, only temperature in autumn is in significant increasing trend; (2) precipitation changes present different properties. Generally, increasing precipitation can be detected. However, only the precipitation in the Tienshan mountain area is in significant increasing trend. Annual streamflow of major rivers of the Tarim River basin are not in significant trends, except that of the Akesu River which is in significantly increasing trend. Due to the geomorphologic properties of the Tienshan mountain area, precipitation in this area demonstrates significant increasing trend and which in turn leads to increasing streamflow of the Akesu River. Due to the fact that the sources of streamflow of the rivers in the Tarim River basin are precipitation and melting glacial, both increasing precipitation and accelerating melting ice has the potential to cause increasing streamflow. These results are of practical and scientific merits in basin-scale water resource management in the arid regions in China under the changing environment.  相似文献   

9.
We analyzed seasonal and annual variations of the whole layer atmospheric moisture budget and precipitation during 1961–2005 and their associations with large-scale circulation in the Yangtze River basin, China. The results indicated increasing moisture budget in summer and winter, but decreasing moisture budget in spring and autumn. Positive correlations between moisture budget and precipitation illustrate tremendous impacts the moisture budget has on the precipitation changes across the Yangtze River basin. In terms of seasonal variations, significant correlations were observed between precipitation and moisture budget in spring and autumn in the upper Yangtze River basin. Besides, we also analyzed changes of geopotential height. The positive trends of the geopotential height (850 hPa) were observed in the East Asia and the negative trends in the middle and west Pacific Ocean, indicating increasing geopotential height from south to north in east Asia which largely limited the moisture propagation to north China. While decreasing meridional geopotential height from west to east along the Yangtze River basin caused more moisture propagation from the west to the east parts of the study region, which may benefit more precipitation in the middle and lower Yangtze River basin.  相似文献   

10.
The present study explores the spatial and temporal changing patterns of the precipitation in the Haihe River basin of North China during 1957–2007 at annual, seasonal and monthly scales. The Mann–Kendall and Sen’s T tests are employed to detect the trends, and the segmented regression is applied to investigate possible change points. Meanwhile, Sen’s slope estimator is computed to represent the magnitudes of the temporal trends. The regional precipitation trends are also discussed based on the regional index series of four sub-basins in the basin. Serial correlation of the precipitation series is checked prior to the application of the statistical test to ensure the validity of trend detection. Moreover, moisture flux variations based on the NCEP/NCAR reanalysis dataset are investigated to further reveal the possible causes behind the changes in precipitation. The results show that: (1) Although the directions of annual precipitation trends at all stations are downward, only seven stations have significant trends at the 90% confidence level, and these stations are mainly located in the western and southeastern Haihe River basin. (2) Summer is the only season showing a strong downward trend. For the monthly series, significant decreasing trends are mainly found during July, August and November, while significant increasing trends are mostly observed during May and December. In comparison with the annual series, more intensive changes can be found in the monthly series, which may indicate a shift in the precipitation regime. (3) Most shifts from increasing trends to decreasing trends occurred in May–June, July, August and December series, while opposed shifts mainly occurred in November. Summer is the only season displaying strong shift trends and the change points mostly emerged during the late 1970s to early 1980s. (4) An obvious decrease in moisture flux is observed after 1980 in comparison with the observations before 1980. The results of similar changing patterns between monthly moisture budget and precipitation confirmed that large-scale atmospheric circulation may be responsible for the shift in the annual cycle of precipitation in the Haihe River basin. These findings are expected to contribute to providing more accurate results of regional changing precipitation patterns and understanding the underlying linkages between climate change and alterations of hydrological cycles in the Haihe River basin.  相似文献   

11.
Abstract

The objectives of this work are: (a) to statistically test and quantify the decreasing trends of streamflow and sediment discharge of the Yellow River in China during 1950–2005, (b) to identify change points or transition years of the decreasing trends, and (c) to diagnose whether the decreasing trends were caused by precipitation changes or human intervention, or both. The results show that significant decreasing trends in annual streamflow and sediment discharge have existed since the late 1950s at three stations located in the upper, middle, and lower reaches of the Yellow River (P?=?0.01). Change-point analyses further revealed that transition years existed and that rapid decline in streamflow and sediment discharge began in 1985 in most parts of the basin (P?=?0.05). Adoption of conservation measures in the 1980s and 1990s corroborates the identified transition years. Double-mass curves of precipitation vs streamflow (sediment) for the periods before and after the transition years show remarkable decreases in proportionality of streamflow (sediment) generation. All percentiles of streamflow and sediment discharge after the transition years showed rapid reduction. In the absence of significantly decreasing precipitation trends, it is concluded that the decreasing trends were very likely caused by human intervention. Relative to the period before the transition, human intervention during 1985–2005 reduced cumulative streamflow by 13.5, 14.3 and 24.6% and cumulative sediment discharge by 29.0, 24.8 and 26.5%, at Toudaoguai, Huayuankou and Lijin, respectively, showing the quantitative conservation effect in the basin.

Citation Gao, P., Zhang, X.-C., Mu, X.-M., Wang, F., Li, R. & Zhang, X. (2010) Trend and change-point analyses of streamflow and sediment discharge in the Yellow River during 1950–2005. Hydrol. Sci. J. 55(2), 275–285.  相似文献   

12.
1961-2003年间鄱阳湖流域气候变化趋势及突变分析   总被引：21，自引：2，他引：19  
本文利用1961-2003年间鄱阳湖流域14个气象站的气温、降水量、蒸发量等观测数据和8个主要水文站的流量数据,研究该时段内鄱阳湖流域的气候变化趋势、突变及其空间分布的差异．研究表明,鄱阳潮流域气温和降水均在1990年发生突变,继而呈现显著的上升趋势;在季节变化上,冬季平均气温在1986年发生突变,增温显著;夏季降水量和夏季暴雨频率均在1992年发生突变增加,暴雨频率增加是夏季降水量增加的主要原因;蒸发皿蒸发量和参照蒸散量均呈现显著下降趋势,该变化在夏季尤为明显．上述变化趋势均以1990s最为显著,这与长江流域气候变化趋势基本一致．在空间分布上,饶河水系、信江水系和赣江下游等气候变化更为显著．笔者认为,鄱阳湖流域气候变化在长江流域中比较突出．该流域1990s暖湿气候在加强;气温的升高、降水量和暴雨频率的增加以及蒸发量的下降强化了五河流量的增加趋势,由此可大致判定鄱阳湖流域气候变化与洪涝灾害之间可能存在的关系,这可为理解气候变化在该流域的响应和预测该流域未来可能的洪涝灾害提供依据．  相似文献   

13.
Extreme events are drawing increasing concerns in recent decades due to their catastrophic nature. In this case, we thoroughly analysed the statistical behaviours of hydrological extremes in the south China by taking Guangdong province as a case study because of its unshakable position in the economic development in China. Our results further corroborated the fact that the hydrological changes are the integrated consequences of various external factors, basically the human activities and climate changes. Generally, decreasing annual maximum water (AMW) level was observed mainly in the seaward regions characterized by decreasing occurrence frequency of higher AMW level. Streamflow variations are influenced mainly by precipitation changes. Increasing annual maximum streamflow (AMS) can be attributed to the increasing precipitation intensity in recent years. However, in the East River basin, hydrological regulation function of the water reservoirs greatly reduced the AMS. In the lower East River, however, downcutting river channel and notable increases in the cross‐section area caused larger magnitude of decrease in AMW level when compared to AMS. The time when the relations between AMW level and streamflow start to change matches well the time when massive in‐channel sand dredging occurred, showing tremendous influences of human activities on hydrological processes in the lower Pearl River basin. This study will be of great scientific and practical merits in better understanding the statistical behaviours of hydrological extremes under the changing environment and also help to improve human mitigation to natural hazards in south China. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

14.
The abrupt changes in the streamflow and sediment load at nine hydrological stations of the Pearl River basin were systematically analysed by using the simple two‐phase linear regression scheme and the coherency analysis technique. Possible underlying causes were also discussed. Our study results indicated that abrupt changes in the streamflow occurred mainly in the early 1990s. The change points were followed by significant decreasing streamflow. Multiscale abrupt behaviour of the sediment load classified the hydrological stations into two groups: (1) Xiaolongtan, Nanning and Liuzhou; and (2) Qianjiang, Dahuangjiangkou, Wuzhou, Gaoyao, Shijiao and Boluo. The grouped categories implied obvious influences of water reservoirs on the hydrological processes of the Pearl River. On the basis of analysis of the locations and the construction time of the water reservoirs, and also the time when the change points occurred, we figured out different ways the water reservoirs impacted the hydrological processes within the Pearl River basin. As for the hydrological variation along the mainstream of the Pearl River, the water reservoirs have considerable influences on both the streamflow and sediment load variations; however, more influences seemed to be exerted on the sediment load transport. In the North River, the hydrological processes seemed to be influenced mainly by climate changes. In the East River, the hydrological variations tended to be impacted by the water reservoirs. The study results also indicated no fixed modes when we address the influences of water reservoirs on hydrological processes. Drainage area and regulation behaviour of the water reservoirs should be taken into account. The results of this study will be of considerable importance for the effective water resources management of the Pearl River basin under the changing environment. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

15.
This study investigated spatial and temporal patterns of trends of the precipitation maxima (defined as the annual/seasonal maximum precipitation) in the Yangtze River basin for 1960–2005 using Mann–Kendall trend test, and explored association of changing patterns of the precipitation maxima with large-scale circulation using NCEP/NCAR reanalysis data. The research results indicate changes of precipitation maxima from relative stable patterns to the significant increasing/decreasing trend in the middle 1970s. With respect to annual variability, the rainy days are decreasing and precipitation intensity is increasing, and significant increasing trend of precipitation intensity was detected in the middle and lower Yangtze River basin. Number of rain days with daily precipitation exceeding 95th and 99th percentiles and related precipitation intensities are in increasing tendency in summer. Large-scale atmospheric circulation analysis indicates decreasing strength of East Asian summer monsoon during 1975–2005 as compared to that during 1961–1974 and increasing geopotential height in the north China, South China Sea and west Pacific regions, all of which combine to negatively impact the northward propagation of the vapor flux. This circulation pattern will be beneficial for the longer stay of the Meiyu front in the Yangtze River basin, leading to more precipitation in the middle and lower Yangtze River basin in summer months. The significant increasing summer precipitation intensity and changing frequency in the rain/no-rain days in the middle and lower Yangtze River basin have potential to result in higher occurrence probability of flood and drought hazards in the region.  相似文献   

16.
The plausible long‐term trend of precipitation in China and its association with El Niño–southern oscillation (ENSO) are investigated by using non‐parametric techniques. It is concluded that a greater number of decreasing trends are observed than are expected to occur by chance. Geographically, the decreasing trend was concentrated in most parts of China, including the Songliao River, Hai River, Huai River, Yellow River, Zhujiang River, and southern part of the Yangtze River basins, whereas an increasing trend appeared primarily in the western and middle parts of China, mainly including the Inland River basin, and the northern part of the Yangtze River basins. Monthly mean precipitation for the summer and early autumn months generally decreased, with the greatest decrease occurring in August. The precipitation in spring from January to April and later autumn, including September and October, tended to increase. The teleconnection between precipitation and ENSO has been investigated by using the non‐parametric Kendall's τ. The correlation coefficients between the southern oscillation index (SOI) and precipitation show the areas with positive or negative associations. Approximately 20% of the stations exhibit statistically significant correlations between SOI and precipitation, of which 70% show a negative correlation, with most of them appearing in southeast China and several appearing in northwest and northeast China. Similar regional patterns are also observed when the precipitation records are further subdivided into El Niño, La Niña, and neutral periods. Statistical tests for the three kinds of time series were carried out using the non‐parametric Wilcoxon rank‐sum test, and it is noted that the stations with significant differences in precipitation averages are mainly marked in the Yellow River basin and south China. The frequencies of below‐ and above‐average precipitation that occurred during the El Niño, La Niña, and neutral periods are estimated as well. The result shows that greater precipitation may be associated with El Niño episodes in south China, but drought may easily occur during El Niño episodes in the Yellow River basin. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

17.
Z. X. Xu  J. Y. Li  C. M. Liu 《水文研究》2007,21(14):1935-1948
Some previous studies have shown that drying‐up of the lower Yellow River resulted from decreasing precipitation and excessive industrial and agricultural consumption of water from the middle and downstream regions of the Yellow River. On the basis of average air temperature, precipitation, and pan evaporation data from nearly 80 gauging stations in the Yellow River basin, the monotonic trends of major climate variables over the past several decades are analysed. The analysis was mainly made for 12 months and the annual means. The isograms for annual and typical months are given in the paper. The result shows that the average temperature in the study area exhibits an increasing trend, mainly because of the increase of temperature in December, January and February. The largest trend is shown in December and the smallest is in August. There are 65 of 77 stations exhibiting a downward trend for annual precipitation. In all seasons except summer, there is a similar trend in the upstream region of the Yellow River, south of latitude 35°N. It is interesting to note that the pan evaporation has decreased in most areas of the Yellow River basin during the past several decades. April and July showed the greatest magnitude of slope, and the area from Sanmenxia to Huayuankou as well as the Yiluo River basin exhibited the strongest declining trend. The conclusion is that the decreasing pan evaporation results from complex changes of air temperature, relative humidity, solar radiation, and wind speed, and both climate change and human activities have affected the flow regime of the Yellow River during the past several decades. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

18.
1990s长江流域降水趋势分析   总被引：2，自引：0，他引：2  
依据国家气象局提供的实测月降水和日降水资料,运用Mann-Kendall(M-K)非参数检验法验证了降水趋势,并通过空间插补法,由点扩展到面,分析了1990s长江流域降水变化特征,发现1990s长江流域降水变化以降水在时间和空间分布上的集中度的增加为主要特点:时间上,年降水的增加趋势以冬季1月和夏季6月降水的集中增加为主;一日降水量大于等于50mm的暴雨日数和暴雨量在1990s也有了较明显的增加.空间上,年降水、夏季降水、冬季降水的增加都以中下游区的增加为主,尤其以鄱阳湖水系、洞庭湖水系的降水增加为主.1990s长江流域春季和秋季降水的减少以5月和9月两个汛期月份的降水减少为主,除金沙江水系和洞庭湖水系等少数地区外,流域大部分地区降水呈减少趋势.上述1990s出现的降水趋势明显与近年来全球变暖背景下长江流域各地区不同的温度及水循环变异有关.  相似文献   

19.
气候变化和人类活动导致珠江流域水文变化,变化前后洪水频率分布显著不同.运用滑动秩和(Mann-Whitney U test)结合Brown-Forsythe、滑动T、有序聚类和Mann-Kendall检验法,并用累积距平曲线法获取年最大流量序列详细信息,综合确定样本最佳变化节点,并对水文变化成因做了系统分析.在此基础上,对整体序列、变化前后序列用线性矩法推求广义极值分布参数以及不同重现期设计流量.结果表明:(1)西江大部以及北江流域最佳变化节点在1991年左右;东江流域最佳变化节点与该流域内3大控制性水库建成时间基本吻合;(2)变化后,西江、北江年最大流量持续增加,洪峰强度增大,尤其是西江干流年最大流量显著增加;东江流域年最大流量显著减小,洪峰强度降低;(3)变化后,西江与北江洪水风险增加,尤其是下游珠三角地区本身受人类活动显著影响,加之西江与北江持续增加的洪水强度,珠三角地区发生洪水的强度及频次加剧,而东江洪水风险减小.此研究对于珠江流域在变化环境下的洪水风险评估与防洪抗灾具有重要意义.  相似文献   

20.
Abstract

Abstract Monthly precipitation and temperature trends of 51 stations in the Yangtze basin from 1950–2002 were analysed and interpolated. The Mann-Kendall trend test was applied to examine the monthly precipitation and temperature data. Significant positive and negative trends at the 90, 95 and 99% significance levels were detected. The monthly mean temperature, precipitation, summer precipitation and monthly mean runoff at Yichang, Hankou and Datong stations were analysed. The results indicate that spatial distribution of precipitation and temperature trends is different. The middle and lower Yangtze basin is dominated by upward precipitation trend but by somewhat downward temperature trend; while downward precipitation trend and upward temperature trend occur in the upper Yangtze basin. This is because increasing precipitation leads to increasing cloud coverage and, hence, results in decreasing ground surface temperature. Average monthly precipitation and temperature analysis for the upper, middle and lower Yangtze basin, respectively, further corroborate this viewpoint. Analysis of precipitation trend for these three regions and of runoff trends for the Yichang, Hankou and Datong stations indicated that runoff trends respond well to the precipitation trends. Historical flood trend analysis also shows that floods in the middle and lower Yangtze basin are in upward trend. The above findings indicate that the middle and lower Yangtze basin is likely to face more serious flood disasters. The research results help in further understanding the influence of climatic changes on floods in the Yangtze basin, providing scientific background for the flood control activities in large catchments in Asia.  相似文献   

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