Suspended particulate matter in Jiaozhou Bay： Properties and variations in response to hydrodynamics and pollution

Based on water samples collected and observations of currents, tidal levels as well as turbidities taken, respectively over a period of 15 and 7 d, in southwestern Jiaozhou Bay on August, 2001, it was found that: ( i ) the average content of non mineral component amounted to 87% of the suspended sediment matter (SPM) in Jiaozhou Bay,much higher than in estuaries and bays where turbidity is high and mineral particulates dominates; (ii) in contrast to high turbid bays, SPM was generally coarser than bed deposits and in upper water column than in lower water column in Jiaozhou Bay; (iii) in fair weathers, suspended sediment concentration (SPC) varied regularly within tidal cycles and neap-spring cycles, but the regularity was deformed in storms; and (iv) SPC was controlled by settling/resuspension near the bed and by advection at the surface at the study site with a depth of 20 m, suggesting weak vertical exchanges. It was concluded that SPM property of a low turbid bay is sensitive to pollution, and that the maintenance of low turbidity in the bay depends on less SPM supply, low waves and currents, and controlling on discharge of particulate pollutants.     

Apparent ages of suspended sediment and soil erosion of the Pearl River (Zhujiang) drainage basin

The carbon isotopic composition (Δ 14 C,δ 13 C) and apparent ages of suspended sediment were determined in the Pearl River in the years 1998,2000 and 2005.These results indicate that suspended POC consists mostly of young carbon and some old carbon.Apparent ages of suspended POC range from 540 to 2050 a BP.The apparent ages are older in the Xijiang and Beijiang Rivers,while these values are variable in the Dongjiang River,including old and young samples.The suspended POCδ 13 C values increase with increasin...     

长江口外冲淡水区悬浮颗粒物中总有机碳和叶绿素a的碳同位素分布

应用超声提取、固相萃取（SPE）、薄层色谱（TLC）技术,成功提取、分离了海水悬浮颗粒物中的色素类化合物,并对叶绿素a（Chl a）的碳同位素进行了测定,建立了海水悬浮颗粒物中叶绿素组分的TLC分离及稳定碳同位素测定方法.测定了长江口外冲淡水区颗粒有机碳（POC）和Chl a中的碳同位素.发现悬浮颗粒物中Chl a的δ13C介于-28.17‰～-32.29‰之间,平均值-29.75‰;POC的δ13C介于-17.92‰～-23.19‰之间,平均值-20.67‰,Chl a比POC的δ13C偏负9.08‰.表层Chl a的δ13C值由北向南逐渐偏负,由近岸向开阔海域逐渐偏正.     

Regional patterns of particulate spectral absorption in the Pearl River estuary

Knowledge about the spectral absorption properties of marine particulate matters is of important signification for various goals of optical oceanography, among them the most concerns are the bio-optical algorithms for ocean color remote sensing[1], basic theory of light radiative transfer in water column[2], bio-optical models for estima-tion of primary productivity and simulation of the upper ocean ecological process[3,4]. The spectral absorption by marine particulate matter is combined influe…     

Reconstruction of flood events over the last 150 years in the lower reaches of the Changjiang River

The reconstruction of paleofloods in the Holocene has become one research highlight for the present global change study. The core sediments from one newly-emerged bar in the lower Changjiang River (Yangtze River) mainstream were collected for grain size and organic elemental measurements, with aim to reconstruct the flood events over the past 150 years. Major grain size parameters such as mean grain size, probability cumulative curve and C-M diagram of the core sediments clearly indicate the flood event deposition. Furthermore, the TOC/TN ratios in the sediments can indicate flood events considering that during the flash floods, strong surface erosion in the upper and lower reaches of the Changjiang River can transport a large amount of undecomposed plant debris and organic components with relatively low C/N ratios into the lower mainstream. Based on 210Pb dating and sedimentary geochemical results, the research profile recorded several large floods happened from 1850 to 1954, which agrees well with the historical documents and hydrological observations. Interesting to note that the flood events since the 1960s cannot be distinctly recognized on the basis of sediment grain size and organic elemental compositions of the profile, which mainly reflects the intensive human activities over the last fifty years, especially condense dam construction, have significantly changed the characters of suspended sediment into the lower mainstream.     

西安冬季高层公寓室内外颗粒物浓度水平与变化

 以西安市冬季某研究生高层公寓为监测对象, 通过1 min 时间间隔同步监测, 研究了不同楼层室内外空气中颗粒物PM1、PM_2.5、PM₁₀以及总悬浮颗粒物TSP 的质量浓度、分布状况与变化特征。结果表明, 西安市冬季高层公寓存在严重的颗粒物污染, 室内粗颗粒物PM₁₀质量浓度为(65.5±20.0)~(142.0±16.9)μg/m³, 略低于室内空气质量标准, 但室内细颗粒物PM_2.5及超细颗粒物PM1分别为(52.2±14.3)~(111.5±12.2)μg/m³和(50.6±13.9)~(108.7±11.9)μg/m³, 其中PM_2.5质量浓度占总悬浮颗粒物TSP 的50%以上;室外以粗颗粒物PM₁₀为主, 楼层高度与颗粒物质量浓度之间无显著关联。     

鄱阳湖丰、枯水期悬浮体浓度及其粒径分布特征

通过2008年、2009年10月(枯水期)和2011年7月(丰水期)的3次全湖调查,结合鄱阳湖水体采样调查与MODIS同步卫星影像反演悬浮体浓度数据,同时利用LISST-100对鄱阳湖悬浮体粒径进行现场观测,研究了鄱阳湖悬浮体浓度及悬浮体粒径分布规律.结果表明,鄱阳湖表层悬浮体浓度表现为北部、中部高,南部低的空间分布特征;垂向分布上看,一般情况下,表层中层底层;而在风生流及采砂活动影响下的湖区中部和南部部分区域,垂直浓度分布规律不明显.全湖平均悬浮体浓度枯水期大于丰水期,且枯水期全湖悬浮体浓度空间差异较丰水期更小.悬浮体粒度组成主要以粉砂为主,其中细粉砂所占比例最高;全湖悬浮体粒径主要分布在8μm~90μm之间,丰、枯水期分布规律较为一致,枯水期的平均悬浮体中值粒径较丰水期更细.悬浮体中值粒径表现为南粗北细的空间分布特征.从粒径频率谱形态分布上看,主要呈现双峰、三峰的粒径分布形态,北部湖区悬浮体粒径谱形态时空分布基本一致;而南部大湖区,丰、枯水期粒径谱分布有较大差异.鄱阳湖悬浮体浓度及粒度分布特征主要是受到水动力、底质及冲淤状态、生物絮凝及人为采砂活动等因素共同影响的结果.     

基于HJ-1卫星CCD数据的长江中游武汉河段悬浮物浓度反演

环境一号(HJ-1)卫星是我国自发研制的专门用于环境和灾害监测的光学卫星.其数据获取周期短、空间分辨率高,能及时、连续、准确地监测悬浮物浓度时空变化,在内陆二类水体遥感监测方面具有良好的应用前景.该文以长江中游武汉河段为研究区,利用HJ-1卫星CCD数据第1、3波段建立了具有较高精度的悬浮物浓度反演模型,并对2008年11月14日武汉河段悬浮物浓度进行了反演,得到其空间分布图.结果表明,该模型的悬浮物浓度反演均方根误差(RMSE)为8.84mg/L,平均绝对百分比误差(MAPE)为13.6%.从空间分布来看,在武汉附近,长江干流悬浮物浓度高于支流汉江,江心洲滩附近水体悬浮物浓度偏高.     

人类活动对河流入海流量下降的影响——以长江黄河为例

近几十年来随着我国经济的飞速发展，人类活动日益加剧且对水资源的需求急剧增加，众多河流的人海流量迅速下降甚至断流，这使得我国水资源私有制的状况日益严重。该文简述我国两大河流长江和黄河的径流量变化情况，主要分析了人类活动地河流入海流量下降的影响。     

长江中下游防治自然灾害的若干对策

长江中下游是个自然灾害种类繁多、发生频繁的地区．从科技进步的角度对该地区防治自然灾害的对策进行了研究,认为必须顺应自然规律,合理利用自然资源;将传统经验与现代科技相结合;将工程措施与生物措施相结合;以科技为依托,建立减灾系统。     

长江流域经济林发展中存在的问题和对策

通过对湖南、湖北、江西、安徽等省长防林建设的实地考察,结合对当地自然社会经济条件的分析,对长防林建设过程中发展经济林的意义、应遵循的原则、存在的问题及发展策略进行了全面的分析。对水土流失严重的经济林分布区进行技术改造、做好退耕还林地上发展经济林的规划、适当调整经济林生产布局、建立高效经济林生产基地、强化政府的宏观指导是在长防林建设过程中发展经济林的主要对策。     

2007年长江安庆段水环境质量的监测与评价

根据长江安庆段2007年水质监测结果,对2007年长江安庆段水环境质量进行了综合评价,分析了长江安庆段污染物浓度变化趋势。由于各监测断面的首要污染物均为有机污染,从皖河口至石化总排江段,安庆市排江的生活污水对江水水质影响较大;从石化总排至前江口断面内,梅罗指数逐渐衰减到近似于皖河口的水平,说明了污染物在长江安庆段得到了很好的消减,同时也说明长江安庆段的纳污能力满足安庆市污水排放的需要。     

长江口及其邻近海域近代沉积物中甲藻孢囊的垂直分布

于2005年4～5月,在长江口外及浙江中南部海域设置5个采样站点,获取了15～40 cm的沉积物柱状样,分层研究了甲藻(dinoflagellates)孢囊的垂直分布.在本研究中共鉴定出46种甲藻孢囊,其中自养型19种,异养型27种.长江口海域复杂的流系特征及环境状况对孢囊分布有明显影响,致使孢囊丰度较低,平均丰度为366.2cysts·g-1,且无明显垂直分布规律.锥状斯氏藻孢囊是最为丰富的自养型甲藻孢囊,平均质量分数介于17.0%～28.9%;异养型甲藻孢囊以原多甲藻属为主,平均质量分数为29.5%～53.6%,其它类型孢囊仅零星分布.有毒藻亚历山大藻孢囊在各站位均有分布,但丰度较低,最高值仅为68.1 cysts·g-1.     

怒江(云南段)大型底栖动物纵向分布和季节性变化规律研究

该文主要通过聚类分析和对应分析方法,以大型底栖动物科级组成上的出现与不出现代替其丰度和生物量,讨论怒江(云南段)大型底栖动物分布格局及季节性变化规律.结果表明:怒江(云南段)大型底栖动物科级组成沿河流纵向分布无明显规律,但具有相同生境类型站点的底栖动物组成较为相似;怒江(云南段)大型底栖动物科级组成春季与秋季相似性高,春、秋季与夏季有明显差异.     

Nd isotopic characteristics of Proterozoic metasedimentary rocks and constraints on their provenance in the eastern segment of Central Tianshan Belt, Xinjiang

Sm-Nd isotopic characteristics, εNd(t) values and Nd model ages (TDM) of Proterozoic metasedimentary rocks in the eastern segment of Central Tianshan Belt (ESCTB), Xinjiang, are used to constrain the sedimentary provenance as well as to evaluate their tectonic implications. εNd(t) and TDM values of these samples range from -4.00 to +6.36 and from 1.29 to 2.29 Ga, respectively. These feature values are distinguished from those of Archean Tarim Craton. Their average εNd(t) values of the Weiya, the Kumishi and the south to the Dikar samples are -2.46, +2.06 and +1.37, respectively. Nd model ages of the Weiya samples vary between 1.86 and 2.29 Ga, but those of the Kumishi and the south to the Dikar samples show a significant concentration at 1.6～1.9 Ga and the youngest Nd model age is 1.29 Ga. Those Nd isotopic characteristics suggest that these metasedimentary rocks could be derived from a significant proportion of Paleoproterozoic crustal source and a participation of young arc materials, rather than Archean Tarim Craton. Furthermore, the data also indicate that these two sources were paleogeographically separated. Thus we can deduce that the Kumishi and the south to the Dikar metasedimentary rocks were formed proximal to the arc side of the back-arc basin, but the Weiya metasedimentary rocks were closer to the continental side of the back-arc basin.     

"引江济淮"输水干线浮游藻类与水体质量研究

拟议中的"引江济淮"工程是一项涉及长江、淮河两大河流的跨流域的调水工程,在对"引江济淮"项目区主要水体调查的基础上,讨论了水体质量以及浮游藻类种类组成与数量以及藻类对水体质量的指示作用.研究表明,巢湖与瓦埠湖及输水河流之间藻类结构具较高的相似性,两湖泊为中或富营养化型湖泊.单纯的输水可能不会改善巢湖和瓦埠湖的水质,应辅以污染的综合治理措施,恢复湖泊的正常生态过程.     

长江中下游环境特征与洪灾的关系

分析长江中下游地区与洪灾密切相关的环境特征,揭示了环境对洪灾的影响规律,指出气候、地形地貌和土壤等是诱发洪灾的自然因素;森林对防洪减灾有巨大作用;水土流失加剧了洪灾发生频率和潜在威胁。最后,对生态环境建设中质量问题、退田还湖、三峡水库的防洪减灾作用等进行了讨论,提出了自己的观点。     

遥感技术在长江江苏段防洪减灾中的应用

应用遥感多时相分析方法对长江岸滩变迁进行动态调查,研究河床的时空演变规律,结合河床边界条件分析及江岸崩坍灾害调查,进行江岸稳定性评价,为长江江苏段治理及防洪减灾提供基础资料和科学依据．结合长江流域生态环境变化的研究,提出长江长治久安的意见和进一步开展遥感工作的建议．     

基于颜色复杂度和结构张量的恰可察觉失真模型

图像的恰可察觉失真(just noticeable distortion, JND)阈值是指人眼能够察觉的最小失真, 通常被用于去除图像/视频压缩中的视觉冗余. 针对 JND 模型对颜色和结构特征利用不充分的问题, 提出了一种基于颜色复杂度和结构张量的 JND 模型. 首先, 计算图像的颜色复杂度, 将其转换为与视觉敏感度相关的权值, 和对比掩蔽模型结合以提升模型的准确性; 然后, 利用结构张量对局部特征进行表示, 建立基于局部结构特征的调制因子, 估计结构不规则区域的视觉冗余程度; 最后, 将基于颜色复杂度的 JND 模型和基于结构张量的调制因子结合, 建立基于颜色复杂度和结构张量的 JND(complexity structure tensor based JND, CSJND)模型. 实验结果表明, 相比于已有的模型, 该模型在主观感知质量相同的前提下, 能使 PSNR 值明显降低; 该模型更加符合人眼的视觉特性, 能更准确地估计出 JND 阈值.