长江口最大浑浊带悬沙浓度变化趋势及成因（英文）

Based on the analysis of suspended sediment elements at estuaries,influence of human activities and estuarine regulation projects on the turbidity maximum zone was studied according to the measurement data between 1959 and 2011.It was found that human activities had little effect on the seaward water while the sharp decrease of sediment volume and concentration in runoff led to the sharp decrease of turbidity maximum zone in the estuary.The concentration at outside sea and Hangzhou Bay did not change,and that along the Subei coast also decreased a little,which had no influence on the turbidity maximum zone.Compared with the concentration between 1959 and 1999,the peak of concentration moved upstream in the estuary,and the concentration in 2000–2009 decreased by about 24.73% with a narrower variation range along the river to the sea.The suspended sediment concentration in North Passage was low in upstream and downstream because of the decrease of seaward sediment and coarsening of bed material,while it was relatively high in the middle due to the influence of sediment cross the north jetty.     

长江口悬沙浓度变化的同步性和差异性(英文)

The sediment discharge from the Yangtze River Basin has a stepwise decreasing trend in recent years. The impounding of the Three Gorges Reservoir exacerbated this decreasing trend and affected the change of the suspended sediment concentration(SSC) in the Yangtze River Estuary through the transmission effect. The SSC data of the Yangtze River Estuary during 1959–2012 showed that:(1) The SSC in the South Branch of the Yangtze River in the estuary and in the off-shore sea area displayed decreasing trends and decreased less towards the sea. At the same time, the difference in decreasing magnitude between SSC and sediment discharge became bigger towards the sea.(2) For the North Branch the preferential flow did not change much but the SSC tended to decrease, which was mainly caused by the decrease of SSC in the South Branch and China East Sea.(3) Due to the decreased runoff and the relatively strengthened tide, the peak area of the SSC in the bar shoal section in 2003–2012 moved inward for about 1/6 longitude unit compared with that in 1984–2002, and the inward-moving distance was in the order of flood season > annual average > dry season.(4) In the inlet of the South Passage, the SSC decreased mainly because the increase caused by resuspension and shore-groove exchange was less than the decrease caused by the sharp SSC decrease in the basin and the sea areas. The reverse was true in the middle section, where the SSC showed an increasing trend.(5) In the inlet of the North Passage, under the combined influence of decreased flow split and sediment split ratios, the decreased SSC in the basin and the sea area and decreased amount of resuspension, the SSC displayed a decreasing trend. In the middle section, because the increased amount caused by sediment going over the dyke was markedly more than the decreased amount caused by external environments, the SSC tended to increase. Holistically, the sharp decrease in sediment discharge caused synchronized SSC decreases in the Yangtze River Estuary. But there were still areas, where the SSC displayed increasing trends, indicating synchronicity and difference in the response of SSC to the sharp decrease in sediment discharge from the basin.     

近60年黄河水沙变化及其对三角洲沉积的影响

In order to find out the variation process of water-sediment and its effect on the Yellow River Delta, the water discharge and sediment load at Lijin from 1950 to 2007 and the decrease of water discharge and sediment load in the Yellow River Basin caused by human disturbances were analyzed by means of statistics. It was shown that the water discharge and sediment load into the sea were decreasing from 1950 to 2007 with serious fluctuation. The human activities were the main cause for decrease of water discharge and sediment load into the sea. From 1950 to 2005, the average annual reduction of water discharge and sediment load by means of water-soil conservation practices were 2.02×109 m3 and 3.41×108 t respectively, and the average annual volume by water abstraction for industry and agriculture were 2.52×1010 m3 and 2.42×108 t respectively. The average sediment trapped by Sanmenxia Reservoir was 1.45×108 t from 1960 to 2007, and the average sediment retention of Xiaolangdi Reservoir was 2.398×108 t from 1997 to 2007. Compared to the data records at Huanyuankou, the water discharge and sediment load into the sea decreased with siltation in the lower reaches and increased with scouring in the lower reaches. The coastline near river mouth extended and the delta area increased when the ratio of accumulative sediment load and accumulative water discharge into the sea (SSCT) is 25.4–26.0 kg/m3 in different time periods. However, the sharp decrease of water discharge and sediment load into the sea in recent years, especially the Yellow River into the sea at Qing 8, the entire Yellow River Delta has turned into erosion from siltation, and the time for a reversal of the state was about 1997.     

长江口水域悬沙浓度时空变化与泥沙再悬浮

A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary. The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls soatial distribution of SSC.     

1950-2008年黄河入海水沙变化(英文)

Based on hydrological data observed at Lijin gauging station from 1950 to 2008, the temporal changes of water discharge and sediment load of the Yellow River into the sea were analyzed by the wavelet analysis, and their impacts on the estuary were investigated in different periods based on the measured coastline and bathymetry data. The results show that: (1) there were three significant periodicities, i.e. annual (0.5-1.0-year), internnual (3.0-6.5-year) and decadal (10.1-14.2-year), in the variations of water discharge and sedi- ment load into the sea, which might be related to the periodic variations of El Nino and Southern Oscillation at long-term timescales. Variations of water discharge and sediment load were varying in various timescales, and their periodic variations were not significant during the 1970s-2000s due to strong human disturbances. (2) The long-term variation of water discharge and sediment load into the sea has shown a stepwise decrease since the 1950s due to the combined influences of human activities and precipitation decrease in the Yellow River Basin, and the human activities were the main cause for the decrease of water discharge and sediment load. (3) The water discharge and sediment load into the sea greatly influenced the evolution of the Yellow River Estuary, especially the stretch rate of coastline and the deposition rate of the sub-aqueous topography off the estuary which deposited since 1976.     

渤海海洋悬浮泥沙二元特征参数MODIS遥感反演模型研究

This paper brought out a new idea on the retrieval of suspended sediment concentration, which uses both the water-leaving radiance from remote sensing data and the grain size of the suspended sediment. A principal component model and a neural network model based on those two parameters were constructed. The analyzing results indicate that testing errors of the models using the two parameters are 0.256 and 0.244, while the errors using only water-leaving radiance are 0,384 and 0.390. The stability of the models with grain size parameter is also better than the one without grain size. This research proved that it is necessary to introduce the grain size parameter into suspended sediment concentration retrieval models in order to improve the retrieval precision of these models.     

Summer fast ice evolution off Zhongshan Station,Antarctica

Based on the field data acquired in the program of fast ice observation off Zhongshan Station,Prydz Bay,East Antarctica during the austral summer 2005/ 2006,physical properties evolution of fast ice during the ice ablation season is ana- lyzed in detail.Results show that the annual maximum ice thickness in 2005 occurred in later November,and then ice started to melt,and the ablation duration was 62 days;sea water under the ice became warmer synchronously;corresponding to the warming sea ice temperature,a"relative cold mid-layer"appeared in sea ice;the fast ice marginal line recoiled back to the shore observably,and the recoil distance was 20.9 km from 18 December 2005 through 14 January 2006.In addition,based on the data of sea ice thickness survey along the investigation course of MV Xuelong on December 18 of 2005,the ice thickness distribution paten in the marginal ice zone have been described:sea ice thickness increased,but the diversity of floe ice thick- ness decreased from open water to fast ice zone distinctly.     

1986-2015年小浪底水库运行前后黄河下游主槽调整规律

Based on the measured discharge,sediment load,and cross-sectional data from 1986 to 2015 for the lower Yellow River,changes in the morphological parameters(width,depth,and cross-sectional geomorphic coefficient)of the main channel are analyzed in this paper.The results show that before the operation of the Xiaolangdi Reservoir(XLDR)from 1986 to 1999,the main channel shrunk continually,with decreasing width and depth.The rate of reduction in its width decreased along the river whereas that of depth increased in the downstream direction.Because the rate of decrease in the width of the main channel was greater than that in channel depth,the cross-sectional geomorphic coefficient decreased in the sub-reach above Gaocun.By contrast,for the sub-reach below Gaocun,the rate of decrease in channel width was smaller than that in channel depth,and the cross-sectional geomorphic coefficient increased.Once the XLDR had begun operation,the main channel eroded continually,and both its width and depth increased from 2000 to 2015.The rate of increase in channel width decreased in the longitudinal direction,and the depth of the main channel in all sub-reaches increased by more than 2 m.Because the rate of increase in the depth of the main channel was clearly larger than that of its width,the cross-sectional geomorphic coefficient decreased in all sub-reaches.The cross-sectional geometry of the main-channel of the lower Yellow River exhibited different adjustment patterns before and after the XLDR began operation.Before its operation,the main channel mainly narrowed in the transverse direction and silted in the vertical direction in the sub-reach above Aishan;in the sub-reach below Aishan,it primarily silted in the vertical direction.After the XLDR began operation,the main channel adjusted by widening in the transverse direction and deepening in the vertical direction in the sub-reach above Aishan;in the sub-reach below it,the main channel adjusted mainly by deepening in the vertical direction.Compared with the rates of decrease in the width and depth of the main channel during the siltation period,the rate of increase in channel width during the scouring period was clearly smaller while the rate of increase in channel depth was larger.After continual siltation and scouring from 1986 to 2015,the cross-sectional geometry of the main-channel changed from wide and shallow to relatively narrow and deep.The pattern of adjustment in the main channel was closely related to the water and sediment conditions.For the braided reach,the cross-sectional geomorphic coefficient was negatively correlated with discharge and positively correlated with suspended sediment concentration(SSC)during the siltation period.By contrast,the cross-sectional geomorphic coefficient was positively correlated with discharge and negatively correlated with SSC during the scouring period.For the transitional and meandering reaches,the cross-sectional geomorphic coefficient was negatively correlated with discharge and positively correlated with SSC.     

青藏高原植被覆盖变化与降水关系

The temporal and spatial changes of NDVI on the Tibetan Plateau, as well as the relationship between NDVI and precipitation, were discussed in this paper, by using 8-km resolution multi-temporal NOAA AVHRR-NDVI data from 1982 to 1999. Monthly maximum NDVI and monthly rainfall were used to analyze the seasonal changes, and annual maximum NDVI, annual effective precipitation and growing season precipitation (from April to August) were used to discuss the interannual changes. The dynamic change of NDVI and the corre- lation coefficients between NDVI and rainfall were computed for each pixel. The results are as follows: (1) The NDVI reached the peak in growing season (from July to September) on the Tibetan Plateau. In the northern and western parts of the plateau, the growing season was very short (about two or three months); but in the southern, vegetation grew almost all the year round. The correlation of monthly maximum NDVI and monthly rainfall varied in different areas. It was weak in the western, northern and southern parts, but strong in the central and eastern parts. (2) The spatial distribution of NDVI interannual dynamic change was different too. The increase areas were mainly distributed in southern Tibet montane shrub-steppe zone, western part of western Sichuan-eastern Tibet montane coniferous forest zone, western part of northern slopes of Kunlun montane desert zone and southeastern part of southern slopes of Himalaya montane evergreen broad-leaved forest zone; the decrease areas were mainly distributed in the Qaidam montane desert zone, the western and northern parts of eastern Qinghai-Qilian montane steppe zone, southern Qinghai high cold meadow steppe zone and Ngari montane desert-steppe and desert zone. The spatial distribution of correlation coeffi- cient between annual effective rainfall and annual maximum NDVI was similar to the growing season rainfall and annual maximum NDVI, and there was good relationship between NDVI and rainfall in the meadow and grassland with medium vegetation cover, and the effect of rainfall on vegetation was small in the forest and desert area.     

黄河三角洲潮滩潮沟近期变化遥感监测

Integrating remote sensing, geographic information system (GIS) and fractal theory, change characteristics of tidal flats and tidal creeks in the Huanghe (Yellow) River Delta over the period of 1986-2001 were discussed. The results show that evolutions of tidal fiats throughout the Huanghe River Delta are influenced by various factors, and that progressive succession and regression of tidal flats concur in different coastal segments of the delta. Human activities have played an increasingly important role in the succession process of tidal flats. Due to land reclamation in coastal zones of the delta in the last 15 years, lots of tidal flats were occupied, the artificial coastline migrated seaward (the maximum change rate was 0.8 kmyr^-1) and tidal creeks became sparser (the highest decreasing rate of length of tidal creeks was 14.9 kmyr^-1). Except for two coastal segments from the Tiaohe Estuary to the 106 Station and from the south of the Huanghe River mouth to the north of the Xiaodao River Estuary,fractal dimension values of tidal creeks in the remaining coastal segments of the delta decreased. In addition, the time dimension, sediment fluxes into the sea, waves and tidal-currents have profound influences on the evolution process of tidal flats. Four types of tidal flats-river-dominated tidal flats,tide-dominated tidal flats, wave-dominated tidal flats and man-dominated tidal flats can be identified.Owing to the intensification of human activities in coastal zones of the delta, man-dominated tidal flats have become the main kind of tidal flats.     

Suspended sediment load in the turbidity maximum zone at the Yangtze River Estuary：The trends and causes

Based on the analysis of suspended sediment elements at estuaries, influence of human activities and estuarine regulation projects on the turbidity maximum zone was studied according to the measurement data between 1959 and 2011. It was found that human activities had little effect on the seaward water while the sharp decrease of sediment volume and concentration in runoff led to the sharp decrease of turbidity maximum zone in the estuary. The concentration at outside sea and Hangzhou Bay did not change, and that along the Subei coast also decreased a little, which had no influence on the turbidity maximum zone. Compared with the concentration between 1959 and 1999, the peak of concentration moved upstream in the estuary, and the concentration in 2000-2009 decreased by about 24.73% with a narrower variation range along the river to the sea. The suspended sediment concentration in North Passage was low in upstream and downstream because of the decrease of seaward sediment and coarsening of bed material, while it was relatively high in the middle due to the influence of sediment cross the north jetty.     

长江口最大浑浊带悬沙浓度变化趋势及成因

基于长江河口1959-2011 年实测悬沙浓度数据,通过对河口最大浑浊带外围海域泥沙要素分析的基础上,研究了近期流域人类活动和河口整治工程对最大浑浊带悬沙浓度的影响。研究表明:① 流域人类活动对入海水量影响较小,无明显趋势变化,而沙量和含沙量呈现锐减趋势,也使得进入河口区域的泥沙量呈现一致锐减;② 长江口外海域和南部杭州湾海域悬沙浓度变化不大,北部苏北沿岸略有减小,因数值较长江口海滨区小约1 个数量级,对浑浊带影响较小;③ 最大浑浊带位置受径流和潮流控制,面积变化与入海沙量多寡关系密切;④ 整个浑浊带区域悬沙浓度受入海沙量锐减决定,2000-2009 年较1959-1999 年悬沙浓度减小约为24.73%,向海延伸减幅降低,且峰值区域向口内移动,泥沙再悬浮作用对维持最大浑浊带悬沙浓度起调节作用,但不能决定其锐减趋势;⑤ 北槽航槽最大浑浊带的悬沙浓度向海为低—高—低变化特点,受入海沙量锐减、北槽分流分沙比减少及床沙粗化等影响,使其上段和下段悬沙浓度减小趋势,而中段受南导堤越堤沙量的影响悬沙浓度呈增加趋势。     

The synchronicity and difference in the change of suspended sediment concentration in the Yangtze River Estuary

The sediment discharge from the Yangtze River Basin has a stepwise decreasing trend in recent years. The impounding of the Three Gorges Reservoir exacerbated this decreasing trend and affected the change of the suspended sediment concentration (SSC) in the Yangtze River Estuary through the transmission effect. The SSC data of the Yangtze River Estuary during 1959-2012 showed that: (1) The SSC in the South Branch of the Yangtze River in the estuary and in the off-shore sea area displayed decreasing trends and decreased less towards the sea. At the same time, the difference in decreasing magnitude between SSC and sediment discharge became bigger towards the sea. (2) For the North Branch the preferential flow did not change much but the SSC tended to decrease, which was mainly caused by the decrease of SSC in the South Branch and China East Sea. (3) Due to the decreased runoff and the relatively strengthened tide, the peak area of the SSC in the bar shoal section in 2003-2012 moved inward for about 1/6 longitude unit compared with that in 1984-2002, and the inward-moving distance was in the order of flood season > annual average > dry season. (4) In the inlet of the South Passage, the SSC decreased mainly because the increase caused by resuspension and shore-groove exchange was less than the decrease caused by the sharp SSC decrease in the basin and the sea areas. The reverse was true in the middle section, where the SSC showed an increasing trend. (5) In the inlet of the North Passage, under the combined influence of decreased flow split and sediment split ratios, the decreased SSC in the basin and the sea area and decreased amount of resuspension, the SSC displayed a decreasing trend. In the middle section, because the increased amount caused by sediment going over the dyke was markedly more than the decreased amount caused by external environments, the SSC tended to increase. Holistically, the sharp decrease in sediment discharge caused synchronized SSC decreases in the Yangtze River Estuary. But there were still areas, where the SSC displayed increasing trends, indicating synchronicity and difference in the response of SSC to the sharp decrease in sediment discharge from the basin.     

长江口悬沙浓度变化的同步性和差异性

近年来长江流域入海沙量呈现阶梯性减小趋势,三峡水库蓄水后加剧了这一减小趋势,并通过传递效应影响河口悬沙浓度变化。基于长江口1950-2013年悬沙浓度数据,结果表明：① 长江口南支河段及口外海域悬沙浓度为减小趋势,且越向海域减幅越小,同时与流域入海沙量减幅差距加大;② 北支优势流变化不大,但悬沙浓度为减小趋势,主要为南支和海域大环境悬沙浓度减小所致;③ 拦门沙河段悬沙浓度的峰值区域因径流减小、潮流相对增强,2003-2012年较1984-2002年期间峰值位置向口内上溯约1/6经度,上溯距离洪季 > 年均 > 枯季;④ 1999-2009年南槽进口悬沙浓度减小,主要是再悬浮和滩槽交换引起的悬沙浓度增量小于流域和海域悬沙浓度锐减引起的减量,中段该作用相反,悬沙浓度为增加趋势;⑤ 北槽进口由于分流分沙比减小、流域和海域悬沙浓度减小及再悬浮量减小等综合影响下,1999-2012年逐年的8月份悬沙浓度呈减小趋势,中段越堤沙量作用明显高于外部坏境引起的减小量,为增加趋势。     

长江河口最大浑浊带水沙输运机制分析

本文根据大量的实测资料，运用机理的分析方法，讨论了长江口最大浑浊带中各输沙项的作用。结果表明，平均流输沙、斯托克斯漂流效应、潮汐捕集以及垂向不流是净输沙的主要部分。     

黄河入海悬沙季节输送变化与输送机制的数值研究(英文)

Based on sediment and discharge flux data for the Yellow River, realistic forcing fields and bathymetry of the Bohai Sea, a suspended sediment transport module is driven by a wave-current coupled model to research seasonal variations and mechanisms of suspended load transport to the Bohai Sea. It could be concluded that surface sediment concentration indicates a distinct spatial distribution characteristic that varies seasonally in the Bohai Sea. Sediment concentration is rather high near the Yellow River estuary, seasonal variations of which are controlled by quantity of sediment from the Yellow River, suspended sediment concentration reaches its maximum during summer and fall. Furthermore, sediment concentration decreases rapidly in other seas far from the Yellow River estuary and maintains a very low level in the center of the Bohai Sea, and is dominated by seasonal variations of climatology wind field in the Bohai Sea. Only a small amount of sediments imported from the Yellow River are delivered northwestward to the southern coast of the Bohai Bay. Majority of sediments are transported southeastward to the Laizhou Bay, where sediments are continuously delivered into the center of the Bohai Sea in a northeastward direction, and part of them are transported eastward alongshore through the Bohai Strait. 69% of sediments from the Yellow River are deposited near the river delta, 31% conveyed seaward, within which, 4% exported to the northern Yellow Sea through the Bohai Strait. Wind wave is the most essential contributor to seasonal variations of sediment concentration in the Bohai Sea, and the contribution of tidal currents is also significant in shallow waters when wind speed is low.     

三角洲岸线变迁中的河流纵剖面实验

现代三角洲岸线变辽对河口变化频繁的河流有着不可忽视的影响.通过各种进口水沙过程和尾水位过程组合的水槽实验,建立了冲积河流纵剖面的发育模式.     

Numerical simulation on seasonal transport variations and mechanisms of suspended sediment discharged from the Yellow River to the Bohai Sea

Based on sediment and discharge flux data for the Yellow River, realistic forcing fields and bathymetry of the Bohai Sea, a suspended sediment transport module is driven by a wave-current coupled model to research seasonal variations and mechanisms of suspended load transport to the Bohai Sea. It could be concluded that surface sediment concentration indicates a distinct spatial distribution characteristic that varies seasonally in the Bohai Sea. Sediment concentration is rather high near the Yellow River estuary, seasonal variations of which are controlled by quantity of sediment from the Yellow River, suspended sediment concentration reaches its maximum during summer and fall. Furthermore, sediment concentration decreases rapidly in other seas far from the Yellow River estuary and maintains a very low level in the center of the Bohai Sea, and is dominated by seasonal variations of climatology wind field in the Bohai Sea. Only a small amount of sediments imported from the Yellow River are delivered northwestward to the southern coast of the Bohai Bay. Majority of sediments are transported southeastward to the Laizhou Bay, where sediments are continuously delivered into the center of the Bohai Sea in a northeastward direction, and part of them are transported eastward alongshore through the Bohai Strait. 69% of sediments from the Yellow River are deposited near the river delta, 31% conveyed seaward, within which, 4% exported to the northern Yellow Sea through the Bohai Strait. Wind wave is the most essential contributor to seasonal variations of sediment concentration in the Bohai Sea, and the contribution of tidal currents is also significant in shallow waters when wind speed is low.     

长江河口悬沙的运动方式与沉积形态特征分析

长江河口为三级分汊四口入海的中等潮汐强度的三角洲河口。长江河口的悬沙输运有净上移、净下泄、上层下泄而下层上溯、潮滩与主槽之间的泥沙交换及涨潮槽泥沙倒灌落潮槽等五种形式。根据悬沙沉积的不同地点不同沉积形态可分为暗沙、拦门沙、口外水下三角洲以及河口潮滩四种类型。     

珠江三角洲干流汊道泥沙分配及变化--以西、北江三角洲为例

通过对６０年代和９０年代珠江三角洲河网典型汊河泥沙分配变化的对比分析,认为（１）珠江河口区的泥沙主要来自陆相径流挟带的下行泥沙和随潮流挟带的上溯泥沙,其中径流及其挟带的泥沙是现代珠江三角洲建造过程中的基本动力和物质,起着主导作用,而珠江河口区由径流挟带的悬移质泥沙又主要来自西江。（２）西北江干沙处于逐年淤积的总趋势,其中河流段冲淤变化不大,过渡段有冲有淤,以淤为主,潮流段由是普遍淤积。（４）海平面