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文章基于近60年来的钦江水沙数据,通过变差系数和贡献率计算法分析钦江在极端天气下的水沙变化。结果表明：1)热带气旋年正常天气的平均流量为32 m3/s,热带气旋过境的平均流量为290 m3/s,是正常天气的9.06倍;热带气旋年的正常天气的平均输沙量是0.05×104 t,热带气旋过境期间的平均输沙量为1.15×104 t,是正常天气期间的23倍。2)洪水年正常天气的平均流量在375 m3/s,而洪水期平均流量在2 725 m3/s左右,是正常天气平均流量的7.27倍。洪水年的正常天气的平均输沙量为0.07×104 t,而洪水期的平均输沙量为1.14×104 t,是正常天气输沙量的16.28倍。3)热带气旋对钦江的径流量平均多年贡献率为10.75%,输沙量贡献率为20.95%;洪水对钦江的径流量平均多年贡献率为16.75%,输沙量贡献率为30.07%。极端天气对钦江的水沙变化具有重要贡献,极端天气发生期间钦江具有... 相似文献
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红水河是珠江流域的主要泥沙来源,为了确定1955-2016年红水河流域输沙量变化特征及其影响因素,论文尝试采用有序聚类分析确定了流域输沙量变化的3个时期,并利用泥沙归因诊断分析计算了含沙量、径流系数和降雨因子在不同时期对输沙量变化的贡献程度,在此基础上进一步对影响输沙量变化的主要因素进行了分析。研究表明：1955-2016年间红水河流域输沙量存在1963和1991年2个突变点,在突变点前后输沙量存在明显变化,且这一变化主要受含沙量因子控制,人类活动是造成流域输沙量变化的根本原因。其中在1955-1991年间,红水河输沙量的上升主要由毁林开荒引起的流域水土流失面积增加所导致;而在1964-2016年间,水库修建使红水河流域输沙量减少了83.49%,而同时期植被覆盖度的增长贡献了输沙量减少的12.03%。将WaTEM/SEDEM模型模拟结果与实测结果进行对比,同样发现1964-2016年输沙量变化的绝大部分(81.03%)由修建水库所贡献,而土地利用变化对输沙量减少的贡献相对较小(18.97%)。 相似文献
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特枯水情对长江中下游悬浮泥沙的影响 总被引：3，自引：0，他引：3
基于长江中下游气象资料、历史水沙资料和2006 年10 月现场水沙观测资料, 分析了 典型枯水年大通站的月均径流量和输沙率特征、2006 年特枯水情产生的气候背景以及对长江中下游含沙量和悬沙粒径产生的影响。分析表明, 枯水年长江干流输沙量有显著的减少, 2006 年特枯水情下大通站汛期输沙量仅占多年平均值(1985-2000 年) 的19.8%。在特枯水情 和三峡工程蓄水的背景下, 2006 年10 月长江中下游含沙量平均为0.057 kg/m3, 只占 2003-2005 年10 月平均值的20.6%。2006 年10 月长江中下游悬沙中值粒径平均为4.8 µm, 悬沙中值粒径只占多年平均值的26.3%, 占近期平均值的41.8%。含沙量、悬沙粒度和中游 河床冲淤特性的综合分析表明, 城陵矶-湖口河段水沙垂向交换强, 是三峡兴建以后近期河 道调整频繁的河段。洞庭湖和鄱阳湖对长江干流含沙量的贡献较大, 尤以鄱阳湖的贡献最大, 长江中下游其他支流对长江干流含沙量的贡献较小。汉江和巢湖对长江中下游悬沙粒径的影响相对较大, 而洞庭湖和鄱阳湖则对悬沙粒径的影响相对较小。 相似文献
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选择12个树木年轮宽度年表和28个气象站的降水量资料分别建立甘肃树轮宽度场和降水量场。树轮气候响应分析发现树轮宽度场第一主成分与甘肃28个气象站上年7月至当年6月降水量第一主成分有较好相关性,相关系数为0.580 (p<0.001)。利用线性回归模型重建甘肃上年7月至当年6月降水量第一主成分,方差解释量为33.6% (1961—2006年)。在1768—2006年期间甘肃有11个降水量较多的时期(高于多年平均值)和11个降水量较少的时期(低于多年平均值),分别反映了东亚夏季风较强和较弱的时期。同时,降水量重建序列的低值与西北地区极端干旱历史事件有着良好的一致性。空间相关分析表明该重建序列能够表征甘肃大范围的降水量变化,与实测降水量资料的第一主成分空间变化较为一致。多窗谱分析发现,甘肃降水量具有36.6年(95%)、11.2年 (95%)、4.8年(95%)、3.4年 (95%)、3.1年(95%)、2.6年(95%)和2.4年(99%)的周期变化。甘肃降水量与亚洲中纬度西风区、季风区树轮降水量序列之间存在一定的关联性,甘肃降水量变化与季风降水量的关联要大于与西风区降水量。 相似文献
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51 年来珠江流域输沙量的变化 总被引：11，自引：0，他引：11
根据1955~2005 年珠江流域主要水文站的径流量和输沙量数据以及流域降水量数据, 对珠江流域输沙量的变化进行了研究, 结果发现: (1) 石角站(北江)、博罗站(东江)、迁江站 (红水河) 以及高要站(西江干流) 输沙量呈下降趋势, 而柳州站(柳江)、南宁站(郁江) 的输沙量则呈上升趋势。(2) 1955~2005 年珠江入海泥沙(石角站、博罗站、高要站输沙量之和) 均 值为7529×104 t/yr, 并在总体上也呈下降趋势。珠江入海泥沙还存在着年际变化上的波动性和阶段性特征, 即从1950 年代到1980 年代呈显著的上升趋势, 而此后呈显著下降趋势。通过分析认为: (1) 气候变化是造成珠江流域输沙量年际波动性变化的主要因素, 但不是造成珠江入海泥沙下降的主要影响因素; (2) 珠江流域入海泥沙的阶段性变化特征与水土流失和水土保持相关; (3) 水库建设是造成1955~2005 年珠江流域入海泥沙减少的主要因素。(4) 珠江流域入海泥沙将可能进一步减少, 这将对未来珠江河口环境和三角洲的演变产生影响, 加强进一步的研究非常必要。 相似文献
6.
围绕黄河上游沙漠宽谷河段“多大流量能冲动多大含沙量的泥沙”、“不同流量能冲走多少泥沙”两个关键问题,对沙漠宽谷河段的水沙阈值展开深入研究。通过分析各断面历年水量、沙量变化过程,揭示了沙漠宽谷河段各区间河段的冲淤规律,得到不同区间河段、不同含沙量情况下的水沙阈值系列。基于水量平衡原理与输沙量平衡原理,分析各断面冲沙输沙流量、含沙量与输沙量之间的关系,建立场次洪水的河道输沙量计算模型,量化水量与沙量的转化效果。通过实例计算,不考虑沙漠宽谷河段水沙调控时,头道拐站的输沙量为0.124×108 t,沙漠宽谷河段的冲刷量为0.0527×108 t,考虑水沙调控时,输沙量增加近4倍。水沙调控显著改善了沙漠宽谷河道的水沙关系,冲刷了河槽,验证了水沙阈值及输沙量计算的准确性和可靠性。 相似文献
7.
10年来北京地区风沙活动大幅度减少。与1980年以前的多年平均值比较1991-1992年北京地区10站平均大风日数只有34%,风沙日数为21.9%。风沙日下降的原因主要是地面绿化后就地起沙迅速减少。但如果上风地区绿化工作不跟上,还会影响北京的风沙活动。 相似文献
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9.
新疆地表水资源对气候变化的响应初探 总被引：30，自引：10，他引：20
计算新疆三大区域地表水资源与气候的相关性,建立两者间的回归方程,进而探讨新疆地表水资源对气候变化的响应,得到以下几点主要结论:①新疆地表水资源对气候变化的响应具有明显的地域特点:北疆以对水文年降水的正响应为主;南疆以对5~9月温度的正响应为主,以对高山区前年的水文年降水的正响应为辅;东疆对水文年降水的正响应及5~9月温度的负响应并重,对降水的响应更重要些。②北疆:当北疆8站水文年平均降水偏多(或偏少)10%时,北疆地表水资源会偏多或偏少7.2%。③东疆:当沁城5~9月平均温度为多年平均值时,巴音布鲁克水文年降水变化±10%,东疆地表水资源会出现±5.4%的变化;当巴音布鲁克水文年降水为多年平均值时,沁城5~9月平均温度偏高(或偏低)1℃,东疆地表水资源会减少(或增多)8.3%。④南疆:当南疆4站5~9月平均温度为多年平均值时,塔什库尔干前年的水文年降水变化±10%,南疆地表水资源会出现±1.3%的变化;当塔什库尔干前年的水文年降水为多年平均值时,南疆4站5~9月平均温度偏高(或偏低)1℃,南疆地表水资源会增多(或减少)11.7%。 相似文献
10.
《资源与生态学报(英文版)》2017,(4)
生态技术措施对河流年输沙量的影响遵从统计学原理。本文以无定河年输沙量为因变量,以无定河汛期降雨、暴雨和生态技术措施面积为自变量,采用逐步回归方法,分析研究了1956–2007年时段生态技术措施对无定河年输沙量的影响。结果表明,(1)计算建立了由"无定河7–8月降雨量"、"生态技术措施面积"和"无定河最大一日降雨量"等三个自变量组成的非线性回归方程,相关系数R2=0.857,显著性水平?=0.001。(2)调整R2=0.717,说明回归方程"解释"了52年时段无定河年输沙量71.7%的变化。(3)生态技术措施面积的标准化回归系数在三个自变量中绝对值最大,说明其对年输沙量变化的影响最大。(4)通过实施生态技术措施,到2007年治理水平年,即使是在7–8月降雨量和最大一日降雨量均为研究时段内最大值时,计算年输沙量为1.49亿t,仅为历史最大值的36%。 相似文献
11.
2000-2017年河龙区间输沙量锐减归因分析 总被引：3，自引：0，他引：3
2000年以来,黄河输沙量锐减。科学认识黄河输沙量变化原因,具有重要意义。以河龙区间为研究对象,分析了河龙区间输沙量变化趋势,构建了梯田、淤地坝以及植被等大规模生态建设措施的减沙贡献率计算方法,阐述了2000-2017年河龙区间输沙量锐减原因,针对河龙区间输沙量变化趋势和治理格局,提出了河龙区间治理对策。主要结论为：① 1952-2017年,河龙区间年降水量无显著变化趋势,研究区年输沙量呈现极显著减少趋势（p < 0.001）;② 1979年和1999年为研究区输沙量发生突变的两个时间节点（p < 0.05）,1952-1979年区间年均输沙量为9.30亿t,1980-1999年区间年均输沙量为4.20亿t,2000-2017年均输沙量大幅降至1.03亿t,降幅达89%;③ 受植被和梯田共同影响,2000-2015年研究区坡面土壤侵蚀量变化介于1.90亿~5.13亿t之间,且呈下降趋势;2000-2011年河龙区间淤地坝年均拦沙量为1.38亿t;④ 植被恢复是河龙区间输沙量减少的主要原因,贡献率为54%,梯田和淤地坝合计贡献了34%,水库拦沙和引水取沙贡献了12%;⑤ 植被恢复主要导致径流含沙量降低,而淤地坝建设主要降低了流域泥沙输移比。 相似文献
12.
Tony Greer Ian Douglas Kawi Bidin Waidi Shun Jadda Suhaimi 《Singapore journal of tropical geography》1996,16(1):1-21
Resource development in the form of cyclical commercial logging activities results in a short period of often severe land disturbance followed by a prolonged phase of recovery. The monitoring of catchment sediment yield gives some indication of the gross erosion processes within the catchment as a result of the disturbance and may also effectively measure any ameliorative processes. Studies in Ulu Segama, Sabah, East Malaysia, recorded significant increases in stream suspended sediment loads as a result of logging. Stream loads were derived from a combination of daily sample measurements and storm event sampling using automated liquid samplers. Measured loads were then compared to computed loads from sediment discharge rating sets derived from the actual samples. Application of these ratings in the disturbed catchment initially underestimated sediment loads; however, a progressive overestimation of loads occurred as the catchment vegetation recovered. When using sediment rating curves as a tool to measure catchment erosion rates in disturbed environments, considerable caution has to be used. Vegetation recovery is reflected in the rapid recovery of stream water quality, making it necessary to continually review the rating. 相似文献
13.
Land–ocean transfer of sediment by rivers is a key pathway for material transfer on Earth. Contemporary data on the sediment loads of rivers provide clear evidence of significant recent changes in the sediment fluxes of several rivers in response to human impact. The key drivers of increased sediment loads include land clearance for agriculture and other facets of land surface disturbance, including logging activity and mining. Although, programmes for soil conservation and sediment control can result in reduced sediment loads, the trapping of sediment by dams represents the dominant cause of reduced loads. This influence is currently assuming increasing importance at the global scale. Any attempt to link these drivers to changes in the global land–ocean sediment flux must take account of the aggregation and buffering effects that operate in larger basins, which can cause damping and even removal of signals of increasing flux within the upstream basin, and complicate the link between upstream and downstream response to human impact. Further work is required to provide a precise quantitative assessment of the human impact on global land–ocean sediment fluxes and the net effect of increasing and decreasing fluxes. Particular attention must be paid to the temporal perspective and the variation of impact trajectories in different areas of the globe and for river basins of different sizes. 相似文献
14.
鄱阳湖流域水沙时空演变特征及其机理 总被引：12，自引：1，他引：11
运用改进的Mann-Kendall(M-K)趋势与突变检验以及线性回归分析等方法,系统分析了鄱阳湖流域的赣江、抚河、信江、饶河和修河等五大支流的5个主要水文控制站(外洲、李家渡、梅港、虎山、万家埠)1956-2005年的水沙序列,在系统搜集流域内水库信息的基础上,深入探讨了流域内水沙变化的原因.研究结果表明:(1)鄱阳湖流域各支流的水沙变化特征相异;除李家渡站径流无明显变化外,其余4站都有增加趋势(但未达到95%的置信度水平1.五大支流的输沙量变化比较复杂,外洲站、李家渡、梅港站和虎山站的输沙量在1985年以后减少的趋势显著,而万家埠站的输沙量直到1999年才开始减少;(2)森林覆盖率对输沙量变化的影响远远大于其对径流变化的影响,森林对减少湿季径流量的作用不明显,但对枯季径流量增加的影响显著.(3)水利设施(尤其是水库)对五大支流的水沙变化影响很大,尤其对输沙量的影响最为明显,这也是鄱阳湖流域大部分水文观测站输沙量减少的主要原因. 相似文献
15.
Rapid channel erosion in the Rio Puerco watershed of northwest New Mexico has been attributed to land use, climate changes, and internal channel adjustments. The objectives of this study were to assess (1) the impacts of land uses on sediment load, (2) the quantitative relationships between land use and sediment load, and (3) the effectiveness of different erosion control methods. The impacts of land uses on sediment load were assessed via hypotheses that, holding other erosion-related variables constant, sediment load correlates positively with grazing intensity and with density of unpaved roads, and correlates negatively with the number of erosion control treatments. We calculated the average annual sediment load for 17 subbasins of 0.67–17.97 km2 by comparing sediment accumulation at two points in time (mid-1960s and 1999) behind intact sediment retention structures. We assessed land use via grazing records and measurements of unpaved roads generated from aerial photographs. Soil characteristics, vegetation, and physical factors were quantified for each subbasin. Using 18 variables for each subbasin, we employed Mallow's Cp as a selection criterion. We used six statistical models, including multiple regression and principal components analysis, to determine inherent mathematical relationships between significant independent variables and sediment load. The results indicate that sediment load does not correlate with grazing intensity except in small, relatively low-relief basins with fewer bedrock exposures. However, this interpretation may be compromised by the low quality of data available to quantify grazing. Sediment load is highly sensitive to the presence of unpaved roads, which serve as high gradient, channelized conduits of water and sediment during storms. Sediment load does not correlate with erosion control except in the subset of small, relatively low-relief subbasins that also proved sensitive to grazing intensity. Overall, the statistical analyses suggest that the impact of land uses on sediment load can be assessed using the data available although physical factors appear more significant than land use in producing high sediment loads in the Rio Puerco subbasins. Historical erosion control techniques, as implemented in the Rio Puerco watershed, prove largely ineffective against accelerated sediment loads because they have not been appropriately implemented or maintained. 相似文献
16.
基于高要（西江）、石角（北江）和博罗（东江）水文站1954-2011 年的连续径流量和输沙率资料,采用Mann-Kendall 非参数秩次检验和小波分析的方法,分析珠江流域的入海水沙通量变化特征。结果显示：（1）1954-2011 年珠江的入海径流量没有明显变化趋势,但输沙率呈明显下降趋势,其间不同阶段的变化趋势不同：1954-1983 年珠江水沙均处于增长阶段,该阶段气候变化和人类活动对输沙的贡献率分别是70%和30%;1984-1993 年珠江水沙通量呈先降后升（1989 年是转折点）波动阶段,主要与气候变化有关;1994-2011 年珠江的水沙通量均呈下降趋势;气候变化和人类活动对输沙率下降的贡献率分别是20%和80%。（2）龙滩水库蓄水后的2007-2011 年与2006 年以前相比,珠江年均入海径流量减少了14%,而年均入海输沙率是减幅达到70%。这一时期水库蓄水和水土保持对输沙率减少的贡献率达到90%以上;（3）珠江的水沙通量变化具有明显年代际周期和年际周期变化特征,且不同子流域的周期有所不同。例如西江的径流量主要存在24 年和13 年的年代际周期以及4~7 年的年际周期,而输沙率主要存在16 年左右和10 年左右的年代际周期和4~7 年的年际周期;北江径流量主要存在12 年左右年代际周期和2 年左右以及8 年左右的年际周期和和输沙率年代际周期主要13-16 年,而年际周期是4~7 年和2~3 年;东江的径流和输沙率主要存在12 年左右年代际周期和2 年左右以及6 年左右的年际周期。这些年代际和年际变化周期与珠江流域降雨量的变化周期有较好关联性。 相似文献
17.
Bent Hasholt Marek Madeyski 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):38-45
Geografisk Tidsskrift, Danish Journal of Geography 98: 38–45. Water samples have been collected since 1969, at the Lavborg Bridge gauging station, on the river Ansager Å in South-West Jutland. Different regression equations of concentration versus discharge have been tested. The regression equations are used together with daily discharges to compute the daily suspended loads. Comparisons between measured and computedloads for different periods when water samples were taken twice a day suggest that the 25 computed annual load values have an uncertainty of less than ± 10%. The variation in annual loads shown is therefore significant and probably caused by increased rainfall in the eigthies. The average total suspended sediment yield for the 25 year period was 7 t/km2/year, of which the organic load contributed 3.2 t/km2/year. 相似文献
18.
Seasonal controls on sediment delivery in a small coastal plain watershed, North Carolina, USA 总被引：1，自引：0，他引：1
Field measurements of drainage ditch sedimentation and suspended sediment transport were used to construct a simple sediment budget and relate seasonal variations in vegetation and the hydrological characteristics of storms to sediment dynamics in a small agricultural watershed in North Carolina. Results indicate that seasonal variations in crop coverage and vegetation in drainage ditches influence sediment delivery. Following the harvesting of crops and mowing of drainage ditches in late autumn, conditions are favorable to soil erosion and sediment transport through early spring. Storms need not be very intense or produce large rainfall totals to transport significant sediment loads. The maturation of field crops and ditch vegetation in spring produces conditions less conducive to both soil erosion and sediment transport. Intense summer thunderstorms, however, are capable of mobilizing and transporting significant amounts of sediment. The computed sediment yield of 0.1 Mg/ha/yr probably represents a low estimate that, nevertheless, is an order of magnitude less than measured ditch storage and more than two orders of magnitude less than regional estimates of soil loss on Coastal Plain croplands. The results show that headwater ditches may be decoupled from slopes so that much of the eroded soil is stored within small watersheds rather than being transported out of the basin. 相似文献
19.
《自然地理学》2013,34(3):229-251
The proportional contributions of cultivated lands and stream banks as sources of fine sediment loads were quantified in 15 rural watersheds in the Glaciated Appalachian Plateau region of the Susquehanna River basin of New York and Pennsylvania. We utilized a relatively simple method of fingerprinting sediment sources by comparing the concentrations of the nuclear bomb-derived radionuclide 137 Cs in fluvial sediment samples collected from channel margins with sediment from cultivated fields and stream banks. The proportion of fine sediment from bank erosion ranged from none to 100% in the study tributaries, with a median contribution of 53% across the 15 study streams. In one stream with no evidence of bank sediment, anomalously high 137 Cs levels in the samples indicated that the sources were pasture or forest, probably scoured from marshy floodplains upstream of the sampling sites. In the 14 other streams, cultivated lands accounted for an average of 42% of the fine sediment. We discuss sources of eroded bank material and the processes driving stream bank erosion in this glaciated region, and examine the impact of historic mill-dam deposits on bank erosion. 相似文献
20.
TIM STOTT ANNE‐MARIE NUTTALL NICK EDEN KATIE SMITH DARREN MAXWELL 《Geografiska Annaler: Series A, Physical Geography》2008,90(4):299-313
Suspended sediment concentration (SSC) in the Ova da Morteratsch, Switzerland, measured during July 2007 was closely associated with discharge (Q) and showed statistically significant relationships at the p < 0.001 level at the proximal and distal ends of the 600 m pro‐glacial zone. SSC predicted from 10‐minute turbidity records gives a much more detailed insight into SSC fluctuations and identified SSC peaks which do not coincide with discharge peaks. Net (proximal – distal) 10‐minute suspended sediment loads (SSL) are predominantly positive (i.e. suspended sediment is being stored in the reach) for most of the 7–19 July 2007 record. Net (proximal – distal) SSLs correlate closely with discharge for the first part of the record (7–13 July) but from 14 to 19 July suspended sediment exhaustion is in evidence and discrete phases of negative net SSL (i.e. sediment flushing) are likely for up to six hours on three separate days which coincide with phases of high discharge and exhaustion of the glacial suspended sediment sources. Analysis of Q at the Berninabach–Pontresina gauging station (5 km downstream) for the past five years revealed that maximum monthly discharges capable of generating sediment flushing events occur in an average of four months each year. The study emphasises the rapid change in suspended sediment transport and yields with distance from the glacier snout and highlights the importance of measurements as close to the glacier snout as possible if data are to be representative of the glaciated land up‐valley. A better understanding of the processes of sediment exchange and the colonisation and stabilisation of sediment stores by vegetation in such pro‐glacial zones is essential if we are to improve predictions of the impacts of climate change on river sediment dynamics and the subsequent effects on aquatic ecology. 相似文献