Geochemical records in the subaqueous Yangtze River delta and their responses to human activities in the past 60 years

Based on studies of the geochemical elements of core sediments collected from the subaqueous Yangtze River delta front, combined with 210Pb and 137Cs nuclide dating, element recording profiles were set up and anthropogenic impacts on the sedimentary records were considered. The results suggest that (1) The core formed since 1945, of homogeneous clay and silt sediments. (2) The content of most elements underwent little change, but the content of S and Nb increased gradually. In particular concentrations of these elements and heavy metals increased rapidly and were maintained at high levels in the surface and sub-surface layers (i.e. since the 1990s). The elements S, As and Nb and principal factor 4 (F4), which were sensitive to anthropogenic impacts, could be used as indicators of human activities. (3) The value of each indicator has increased gradually since 1945, with a sharp increase over the last 20 years. When divided according to changing values of the indicators at 185 cm (1955), 97 cm (1978), 47 cm (1992), and 7 cm (2003), five periods of the geochemical elements records were obtained. These corresponded to the ages of from the Chinese Civil War to the early stages of planned economy, the implementation of planned economy, the reform and opening-up period, the market economy establishment phase and the environment control and protection stage after 2003, respectively.     

长江水下三角洲YD0901孔记录的全新世以来的古环境信息

分析长江水下三角洲YD 0901孔的粒度、TOC(总有机碳)和TN(总氮),建立全新世以来高分辨率年代地层图(平均分辨率为20a).结果显示,"中全新世大暖期"(距今7ka～6ka)水下三角洲加速营造,同时闽浙泥质区开始缓慢形成.TOC和TN测试数据表明:在距今2.7ka左右,YD0901孔的TN含量逐渐增加,说明流域人类活动逐渐加剧;而TOC由于部分的成岩作用,含量并未明显增加.通过沉积相分析,得到最大海侵面的深度,为准确估算冰后期最大海侵以来水下三角洲沉积总量提供了可靠依据.     

长三角城市旅游业空间集聚研究

根据空间自相关理论分析探讨了旅游业的空间相互作用关系和格局,运用Geo da软件对长三角地区16城市的旅游业发展水平做了定量研究.国内旅游和入境旅游在人次和收入上的全局自相关水平均不显著,Moran's值较低,未通过Z统计检验;旅游业发展不存在显著集聚和分异;旅游业发展水平因城市等级差异呈现相应随机分布格局.城市象限分布图反映出城市等级与旅游业水平对应关系,上海、杭州、南京、苏州是各指标的高值中心,与其他城市的相对低值构成随机分布空间格局,高值城市周边城镇是其服务和旅游辐射区域,旅游业城际间自相关水平开始下降,呈现出网络一体化发展态势.     

长三角区域物流空间演化与影响因素分析

以长三角区域16个核心城市2003年~2012年的物流空间布局演化特征为基础,从需求、供给、产业环境和政策等4个维度选择了影响物流集聚度的影响因素,并实证分析了这些因素对长三角区域物流空间布局变化的影响机理.研究发现:(1)10年来,长三角区域物流的空间布局同时受到集聚效应和扩散效应的作用,各城市物流集聚呈现分化态势,经历了"三心多点"到"两极一心多点",再到"一极一团一走廊"的阶段性演化.(2)长三角区域物流空间布局的演化是区域经济增长、人口规模、劳动力水平和交通运输条件等因素的综合影响的结果,而第二产业的规模对物流集聚程度的影响并不显著.     

长三角地区4种典型土壤对Zn吸附-解吸的特性

选择长三角地区具有代表性的4种土壤,采用不同浓度的外源Zn溶液进行吸附,用模拟雨水作为解吸剂,研究4种土壤对Zn的吸附-解吸特性,以及Zn的连续解吸特性.结果表明:4种土壤对Zn的吸附量均随吸附平衡浓度的增大而增加,且吸附量与土壤的pH正相关;吸附等温线可以用Freundlich方程和Temkin方程来描述.由Langmuir方程求得的4种土壤的最大吸附量的大小顺序为:q(青紫泥)＞q(滩潮土)＞q(乌黄土)＞q(黄泥沙田).最大缓冲容量的顺序为:MBC(滩潮土)＞MBC(乌黄土)＞MBC(青紫泥)＞MBc(黄泥沙田).4种土壤对Zn的解吸量均随着解吸平衡浓度的增大而线性增加.连续解吸可提高土壤对Zn的解吸率,但连续解吸数次后,解吸过程趋于稳定.     

长江中游洪灾的历史地理考察

从历史地理角度考察，长江中游洪灾是其他形水系缺陷，流域环境恶化，堤防修筑草率共同作用的结果，与历史时期相比，现代大型水库一定程度上弥补了其地形水系的缺陷，但与此同时，流域生态环境进一步恶化，堤防抗洪能力依然薄弱，人类环境管理失败所致的流域生态环境恶化依然是长江中游洪灾的根本原因，实施流域综合治理战略是减轻长江中游洪灾的必然选择。     

The trend and fluctuation of historical floods in the middle reaches of the Yangtze River

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长江水患灾害成因及其防治途径

分析了长江水患灾害发生的主要成因即降水量大而集中、森林破坏造成水土流失加剧、水利工程设防标准较低等及其有关区域因素,在此基础上,提出了恢复生态平衡,建立标本兼治的防洪体系的基本思路即改变传统的被动“治水”方式,积极重视“疏导”洪水,统筹规划、加大投入,开展全流域综合治理以及封山育林、限制采伐、退耕还林、涵养水土资源;积极适度退田还湖,加大调蓄干流洪水;加固加高长江干流干堤,建设一批控制性水利水电工程等主要防治途径     

长三角地区新建本科院校专业设置研究

以长三角地区新建本科院校专业设置为调查研究对象,分析了长三角地区新建本科院校专业布点比较集中、布局结构与产业结构基本成正相关等设置现状以及所体现出的时间曲线规律、学科基础规律和产业适应规律;针对长三角地区新建本科院校专业发展不平衡、特色不够明显等问题,提出了提高专业设置有效性、建设特色专业、构建专业退出机制等新建本科院校改进专业设置的建议。     

Differences between dynamics factors for interannual and decadal variations of rainfall over the Yangtze River valley during flood seasons

The prediction of rainfall in the Yangtze River valley, especially, during flood seasons is the main means for scientists in China working on and the understanding of rainfall-associated processes is a crucial component of this effort. It can be derived f…     

Detrital zircon U-Pb ages of Late Cenozoic sediments from the Yangtze delta: Implication for the evolution of the Yangtze River

Detrital zircon grains of Late Cenozoic sediments dated back to ca.3.6 Ma from core DY03 in the Yangtze delta were dated by LA-ICP-MS,in order to investigate the sedimentary provenance and to find some clue for the evolution of the Yangtze River.Most of the detrital zircon U-Pb ages are distributed at 100 300 Ma,350 550 Ma,600 1000 Ma,1400 2000 Ma and 2200 2800 Ma,which correspond well with the main tectonic and magmatic events in the Yangtze drainage.The detrital zircon age patterns show distinct differenc...     

长江三角洲与东海岛屿黄土研究综述

黄土是记录古气候和古环境变化信息的良好载体,长江三角洲平原及东海岛屿晚更新世黄土地层剖面的发现, 证明了末次冰期以来长江三角洲地区及海域均广泛存在风尘黄土堆积的事实,研究表明长江三角洲平原埋藏黄土和东海岛屿黄土是下蜀黄土上部地层在中国东部沿海和海域的延伸和继续.中国东部风尘黄土记录了我国晚更新世以来东部沿海地区的气候变化及东亚季风演变,与中国西北地区黄土地层相比,东部黄土具有沉积厚度小、成因复杂、次生作用强烈的特点;粒度和磁化率等参数垂向变化规律没有西部明显;粘土矿物和常量化学成分显示了东部黄土经历了较强地淋溶作用.在东部风尘黄土研究过程中,更需注意区域环境特征、地貌地形特点以及沉积期后环境变化对风尘黄土沉积物的影响效应,通过多指标的综合验证才能够正确解读黄土地层赋含的环境变化信息以及认识我国东部季风区晚更新世以来的古环境演变过程及规律.     

大长江三角洲地区区域旅游整合模式探究

区域旅游是现代旅游业发展的必然产物,也代表未来旅游业的发展趋势。区域旅游资源及产品整合能够有利于旅游业的快速发展。大长江三角洲地区区域旅游资源丰富,旅游产品多样,由于该区缺乏统一的旅游资源及产品整合,使得该区旅游业的发展受到制约。本文通过对该区旅游资源及产品的丰富性和多样性进行评述及其整合的可行性分析。提出了区域旅游整合模式的对策,以便能促进旅游业的快速发展。     

基于自组织竞争网络的黄河和长江物源判别

利用黄河和长江在地质历史时期的沉积物与现代黄河长江沉积物应具有一定的相似性这一原理,＂将今论古＂,以现代黄河和长江入海沉积物中部分常量元素的百分含量作为基准数据建立自组织竞争网络,对来自不同时代的黄河和长江的沉积物进行判别和验证,可靠性达到94.4%,并规定了其相应置信度下的置信区间.以此为基础,对南黄海NT2孔的物质来源进行了判别,结果表明钻孔中0～19.36m、28.07～52.88m深度范围内的沉积物为长江沉积物,19.36～28.07m、52.88～70.28m深度范围内以及表层沉积物为黄河沉积物.     

Significant relationship between spring AO and the summer rainfall along the Yangtze River

The influence of spring AO on the summer rainfall along the Yangtze River is investigated. The long-term rainfall observations are filtered to remove the low-frequency variations longer than 10 years. The inter-annual components show a high correlation to AO in the last hundred years. The strongest correlation appears for May AO and summer rainfall with a value of -0.39, significant above the 99% confidence level. Associated with one standard deviation stronger May AO index, the rainfall over the Yangtze River to the southern Japan decreases by about 3%-9%, while, at the same time increases by about 3%-6% in the northern China and far-eastern Russia. The coherent changes in rainfall are significantly related to the East Asian summer jet stream in the upper troposphere. When there is stronger AO in spring, the jet stream tends to move polarward in summer, and leads the rainfall-belt to move northward too. That gives rise to a drier condition in the Yangtze River valley, wetter anomalies in northern China. This signal would be helpful for the summer rainfall prediction in China.     

长三角扩容对污染减排的空间分异特征及其机制

基于长三角扩容的准自然实验,选取2008-2017年的211个地级市面板数据,运用双重差分法分析了长三角扩容后相关城市污染排放的影响及其内在机制,同时采用PSM—DID估计、平行趋势检验、合成控制法、安慰剂法等方法对结果进行稳健性检验.研究表明:长三角扩容对污染排放的显著负向作用发生在整体及原位城市,且原位城市的显著负...     

Large and meso-α scale characteristics of intense rainfall in the mid — and lower reaches of the Yangtze River

Meteorological conditions associated with intense rainfall and great floods over mid- and lower reaches of Yangtze River are studied by analyzing the large-, synopticand meso-tα-scale circulation systems for 1991, 1996 and 1998. It is found that the advance and retreat of subtropical high over the West Pacific, the monsoon moisture surge from the South China Sea, cold air outbreak over mid- and high-latitudes, and the meso- tα scale systems (250-2500 km)from the Tibetan Pleateau as well, are responsible for intense rainfall over the Yangtze River Valley. The persistent and heavy rains and great floods over the Yangtze River Valley occurred when all these four systems are synergetic or in phase lock.``     

长江流域生态环境问题及其成因

分析长江流域上中游的水土流失与地质灾害、中下游的洪涝灾害、长江口的赤潮、长江水质污染、流域生物多样性变化、流域内人群健康等问题;论述了长江流域生态环境恶化的成因:森林植被的锐减是造成水土流失的主要因素,区域自然地理特征是洪灾和地质灾害的基础,污染物的大量排放造成了长江水质的污染和长江口的赤潮,水利设施的兴建使得濒危物种增多,城市化增加了洪灾损失;提出了保护和恢复长江流域和谐生态环境的有效措施:增加环境建设的投入和增强人们的环保意识,重视森林植被的保护等.     

长江航道建设新的机遇和挑战及对策

上游水电工程的开发,将极大地促进航运事业的发展,为改善下游通航条件、提高航道等级和尺度提供了良好的条件。在对长江航道现状及问题分析的基础上,探讨了水电开发带来的航道整治的机遇与挑战,提出了相应的航道整治对策。     

我国长江垃圾倾倒防范机制的不足及完善策略——以“长江口倾倒垃圾案”为视角

频繁出现的垃圾倾倒事件已成为建设和谐长江、健康长江、清洁长江、优美长江、安全长江等目标的重要障碍,长江垃圾倾倒防范机制的构建尚存在法律依据不足、责任约束性不够、协同监管机制欠缺等制度障碍,以及地方垃圾处理能力普遍欠缺的现实障碍。我们应秉承创新、协调、绿色、开放、共享发展理念,探讨相应的对策,以扭转长江资源环境约束趋紧的状况,促进长江经济带尽快走上生态优先、绿色发展之路。