Characterizing ionic species in PM2.5 and PM10 in four Pearl River Delta cities；South China

IEECAS SKLLQG

Landscape change detection of the newly created wetland in Yellow River Delta

Four models are employed in the landscape change detection of the newly created wetland. The models include ones for patch connectivity. ecological diversity, human impact intensity and mean center of land cover. The landscape data of the newly created wetland in Yellow River Delta in 1984, 1991, and 1996 are produced from the unsupervised classification and the supervised classification on the basis of integrating Landsat TM images of the newly created wetland in the four seasons of the each year. The result from operating the models into the data shows that the newly created wetland landscape in Yellow River Delta had a great chance. The driving focus of the change are mainly from natural evolution of the newly created wetland and rapid population growth, especially non-peasant population growth in Yellow River Delta because a considerable amount of oil and gas fields have been found in the Yellow River Delta. For preventing the newly created wetland from more destruction and conserving benign Succession of the ecosystems in the newly created wetland, six measures are suggested on the basis of research results. (C) 2003 Elsevier Science B.V. All rights reserved.

Application of rough set-based analysis to extract spatial relationship indicator rules: An example of land use in Pearl River Delta

Spatial relations, reflecting the complex association between geographical phenomena and environments, are very important in the solution of geographical issues. Different spatial relations can be expressed by indicators which are useful for the analysis of geographical issues. Urbanization, an important geographical issue, is considered in this paper. The spatial relationship indicators concerning urbanization are expressed with a decision table. Thereafter, the spatial relationship indicator rules are extracted based on the application of rough set theory. The extraction process of spatial relationship indicator rules is illustrated with data from the urban and rural areas of Shenzhen and Hong Kong, located in the Pearl River Delta. Land use vector data of 1995 and 2000 are used. The extracted spatial relationship indicator rules of 1995 are used to identify the urban and rural areas in Zhongshan, Zhuhai and Macao. The identification accuracy is approximately 96.3%. Similar procedures are used to extract the spatial relationship indicator rules of 2000 for the urban and rural areas in Zhongshan, Zhuhai and Macao. An identification accuracy of about 83.6% is obtained.

Impacts of anthropogenic activity on the recent evolution of the Huanghe (Yellow) River delta

Hydrological statistical data, remote sensing images, and bathymetric charts were used to study the recent evolution of the Huanghe (Yellow) River delta under human-induced interventions. It was clear that water and sediment discharge from the Huanghe River had dropped rapidly since 1970, particularly after 1986. The water and sediment discharges for the period of 1986-2000 were found to have been reduced to only 29.2% and 31.2% of those in the period of 1950-69. This was caused by human factors in the upper and middle reaches of the Huanghe River, including water diversion, damming and reservoir construction, and water and soil conservation. Based on the results from visual interpretation of processed Landsat (MSS or TMJETM+) images dated from 1976 to 2001 and two digital elevation models generated from bathymetric charts surveyed in 1976 and 1992, we found that human-induced reduction of water and sediment discharge led to coastline retrogradation, with the maximum mean recession rate of -0.51 km yr-1 over the period of 1976-98, and seabed erosion beyond the -20 m isobath between 1976 and 1992. Other impacts of human activities on the recent evolution of the Huanghe River delta, including tidal flats shrinking, artificial coastline increasing, land surface sinking and so on, were also analyzed. We found that: (i) the whole delta, including subaerial and subaqueous, has turned from a highly constructive period to a destructive phase; (ii) channelization and dredging were two of the main causes of delta destruction; (iii) land loss in the Huanghe River delta caused by submersion will be increased in the near future; (iv) the Huanghe River delta was becoming more fragile and susceptible to natural hazards.

River mouth bar formation, riverbed aggradation and channel migration in the modern Huanghe (Yellow) River delta, China

This paper addresses the recent (1970s-1990s) processes of river mouth bar formation, riverbed aggradation and distributary migration in the Huanghe River mouth area, in the light of station-based monitoring, field measurements and remote sensing interpretation. The results show that the morphological changes of the river mouth bar have been closely associated with the largely reduced fluvial discharge and sediment load. Landforrn development such as bar progradation occurred in two phases, i.e. before and after 1989, which correspond to faster and lower bar growth rates, respectively. Fast riverbed aggradation in the mouth channel was strongly related to river mouth bar progradation. During 1976-1996, about 2.8% of the total sediment loads were deposited in the river channel on the upper to middle delta. Therefore, the river water level rose by a few meters from 1984 to 1996. The frequent distributary channel migration, which switched the radial channel pattern into the SE-directed pattern in the mid-1980s, was linked with mouth bar formation. Marine conditions also constrain seaward bar progradation. Furthermore, the history of river mouth bar formation reflects human impacts, such as dredging and dyking in order to stabilize the coastal area. (c) 2005 Elsevier B.V. All rights reserved.

Quantitatively distinguishing sediments from the Yangtze River and the Yellow River using delta Eu-N-I REEs pound plot

Sediment samples were collected from the lower channel of the Yangtze River and the Yellow River and the contents of rare earth elements (REEs) were measured. In addition, some historical REEs data were collected from published literatures. Based on the delta Eu-N-I REEs pound plot, a clear boundary was found between the sediments from the two rivers. The boundary can be described as an orthogonal polynomial equation by ordinary linear regression with sediments from the Yangtze River located above the curve and sediments from the Yellow River located below the curve. To validate this method, the REEs contents of sediments collected from the estuaries of the Yangtze River and the Yellow River were measured. In addition, the REEs data of sediment Core 255 from the Yangtze River and Core YA01 from the Yellow River were collected. Results show that the samples from the Yangtze River estuary and Core 255 almost are above the curve and most samples from the Yellow River estuary and Core YA01 are below the curve in the delta Eu-N-I REEs pound plot. The plot and the regression equation can be used to distinguish sediments from the Yangtze River and the Yellow River intuitively and quantitatively, and to trace the sediment provenance of the eastern seas of China. The difference between the sediments from two rivers in the delta Eu-N-I REEs pound plot is caused by different mineral compositions and regional climate patterns of the source areas. The relationship between delta Eu-N and I REEs pound is changed little during the transport from the source area to the river, and from river to the sea. Thus the original information on mineral compositions and climate of the source area was preserved.

The change of characteristics of tidal wave in the Changjiang River mouth area since the post-glacial transgression maximum

During the period of the post-glacial transgression maximum (PGTM), there was a huge trumpet estuary in the modern Changjiang River Delta area. The location and the shape of the Paleo-Changjiang River Estuary (PCRE) were much different from those of the present Changjiang River Estuary. The study on the change of characteristics of tidal wave in the Changjiang River mouth area since the PGTM can help to understand better the dynamic development of the Changjiang River Delta. The course curves of tidal level and tidal current velocity during a single tidal cycle for 35 points are calculated, and characteristics of tidal waves in the PCRE and its adjacent area are compared with those of tidal waves in the modern Changjiang River mouth area. The results show that the tidal waves within the PCRE and in its adjacent area during the period of the PGTM belonged to standing wave or a mixture of standing wave and progressive wave. Since then, the tidal wave in the Changjiang River mouth become gradually to be progressive wave with the PCRE being filled and the Changjiang River mouth shifting southeastwards.

现代黄河三角洲湿地景观变化及其对水禽生境的影响

本文研究的开展主要源于国家海洋局海洋公益性行业科研专项经费项目“渤海典型区域的海洋多过程数据整合研究”课题支撑。在湿地日益退化丧失的全球背景下，本文选择沉积年代较轻、生态环境比较脆弱，且当前人类活动不断加剧的现代黄河三角洲为研究区，采用1999、2001、2004和2008年的Landsat5 TM遥感影像，选择丹顶鹤和黑嘴鸥为指示物种，结合野外实地调查和历史数据资料的整理和分析，以及黄河三角洲自然保护区对鸟类的监测记录结果，开展现代黄河三角洲湿地景观变化及其对水禽生境的影响研究。 论文的主要研究结果如下： 1、建立了服务于黄河三角洲湿地水禽生境保护的湿地景观分类体系 在系统分析研究区域湿地水禽生活习性和生态分布特征的基础上，从鸟类生境选择的概念出发，建立了服务于黄河三角洲湿地水禽生境保护的湿地景观分类体系。该分类体系一共分为4级，其中，第三级分类系统下天然湿地的划分是从鸟类选择的“大生境”角度出发，即根据区域地表类型，进一步将海洋/海岸湿地和内陆三角洲湿地划分成浅海水域、潮间淤泥滩、潮沟、河口水域、潮间盐沼、河流湿地和沼泽湿地7类。而第四级分类系统下天然湿地的划分则是从鸟类选择的“小生境”（即对水、食物、隐蔽物、干扰等的需求）角度出发，并按照水文和典型植被类型，进一步将天然湿地的三级类型划分为碱蓬沼泽、芦苇沼泽、柽柳灌丛沼泽等33类。 2、系统研究了现代黄河三角洲湿地景观格局的动态变化和影响因素 根据景观生态学理论，选取用于分析的景观格局指数，并从湿地景观类型的组成特征变化、面积变化、形状特征变化、空间配置特征变化四个方面分析在黄河断流前到其恢复正常行水至今的时间里三角洲湿地景观格局的动态变化，研究结果表明：在1999~2008年的9年间，天然湿地构成了现代黄河三角洲景观的主体，约占研究区域景观总面积的65%~75%，决定了该地区湿地的主要结构和功能。但随着人类对土地资源利用方式的不断改变和强度的提高，天然湿地景观呈萎缩退化趋势，9年内共减少338.44 km2，约占研究区景观总面积的8.90%。与此同时，盐田、养殖池塘等人工湿地和耕地等非湿地面积不断扩张，人工湿地面积增加量约为242.08km2，约占研究区景观总面积的6.37%，非湿地面积增加量约为96.36 km2，约占研究区景观总面积的2.53%。从一些重要的景观指数的计算结果来看，研究区域整体景观斑块数量呈增加趋势，平均斑块大小随之减小，景观边界密度大小、聚集度指数也呈下降趋势，表明从1999到2008年研究区域整体景观被边界分割的程度加深，整体景观中的斑块在空间分布上隔离程度加重，开始由大片连续分布向小块离散分布转变，景观的破碎化程度加重。 湿地景观格局变化的驱动机制分析表明，影响研究区湿地景观变化的主要因素包括三个方面，即：黄河水沙条件的驱动力、湿地自身演替驱动力和人为驱动力。在1999~2008年的9年间，黄河虽然恢复正常行水，不再断流，但入海泥沙量的明显减少使得除现行河口处沙嘴继续向海缓慢延伸外，黄河三角洲总体上处于侵蚀状态。湿地自身的演替主要体现在湿地由裸露淤泥质滩涂向发育典型湿地植物群落的顺向演替，以及发育有典型湿地植物群落的湿地向裸露淤泥质滩涂逆向演替两个方面。在1999~2008年间9年里，湿地顺向发育演替面积约130.64 km2，而逆向发育演替面积约为99.51 km2。人类活动一直以来都是影响黄河三角洲湿地景观变化不可忽视的营造力。大规模的滩涂围垦和养殖、农业用地的不断开垦和扩张，以及密集的油田开发活动不仅缩减了原本生长着芦苇茅草等植物的天然湿地资源，而且加重了三角洲湿地景观的破碎程度。 3、在整个研究区域尺度上深刻分析了丹顶鹤和黑嘴鸥潜在生境的适宜性 根据黄河三角洲自然保护区关于鸟类的监测记录资料，在深入分析湿地水禽生活习性和分布特征的基础上，选择丹顶鹤和黑嘴鸥为指示物种，从鸟类生境选择自身的特征出发，确定地表类型、水、食物、隐蔽物和干扰为影响两种鸟类类群进行生境选择的因素，并构建生境适宜性评价模型，在整个研究区域尺度上对两种鸟类类群的潜在生境进行适宜性评价和动态变化分析。研究结果表明，在不考虑居民地、油田作业用地和道路等干扰因子对生境产生的破碎化效应影响时，适宜丹顶鹤和黑嘴鸥生存的生境类型在1999~2008年间占研究区整体景观总面积的比重均在30%以上，其中天然湿地约占适宜生境类型面积的95%，可利用的人工湿地比重极小，但呈缓慢增加趋势，且由于可利用的天然湿地生境类型的逐年减少使得适宜两种鸟类类群的生境类型总面积总体上呈萎缩趋势。在考虑居民地、油田作业用地和道路等干扰因子对生境产生的破碎化效应影响时，适宜丹顶鹤和黑嘴鸥生存的生境类型在1999~2008年间占研究区域整体景观总面积的百分比由之前接近40%下降到20%以下，面积减少量均在600 km2以上。 4、系统分析了研究区湿地景观变化对水禽生境的影响 从研究区湿地景观基质的面积变化、形状和空间邻接关系变化、破碎化等三个方面分析了研究区湿地景观变化对丹顶鹤和黑嘴鸥两种鸟类类群生境的影响，结果表明，湿地景观基质中天然湿地的变化与丹顶鹤、黑嘴鸥适宜生境的大小和空间分布密切相关。在1999~2008年间，随着天然湿地面积的减少，适宜以上两种鸟类类群的生境面积也随之减少，两者呈正相关关系；在1999~2008年间，研究区天然湿地和人工湿地景观基质整体的形状指数均在1.0附近，表明湿地景观基质整体上的边缘效应较小，但建设用地、农林用地等非湿地景观与丹顶鹤和黑嘴鸥适宜生境类型中的主导类型——潮间淤泥滩、潮间盐沼和沼泽湿地等三种景观类型的频繁邻接，对于保护两种鸟类类群十分不利，应积极采取相应的措施加强保护力度；在1999~2008年间，研究区景观整体，以及湿地景观基质结构的破碎化，导致鸟类可利用的天然湿地和人工湿地景观内部斑块之间的连接程度下降，从而使得丹顶鹤、黑嘴