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…     

SHRIMP zircon U-Pb dating for volcanic rocks of the Dasi Formation in southeast Hubei Province, middle-lower reaches of the Yangtze River and its implications

The Jinniu Basin in southeast Hubei,located at the westernmost part of middle-lower val-ley of the Yangtze River,is one of the important vol-canic basins in East China. Volcanic rocks in the Jin-niu Basin are distributed mainly in the Majiashan Formation,the Lingxiang Formation and the Dasi Formation,consisting of rhyolite,basalt and basaltic andesite,(trachy)-basalt and basaltic trachy-andesite and (trachy)-andesite and (trachy)-dacite and rhyolite respectively,in which the Dasi volcanism is volumet-rically dominant and widespread. The Dasi volcanic rocks were selected for SHRIMP zircon U-Pb dating to confirm the timing of volcanism. The results indi-cate that there exist a large amount of magmatic zir-cons characterized by high U and Th contents in the volcanic rocks. The concordia ages for 13 points are 128 ± 1Ma (MSWD = 3.0). On account of the shape of zircons and Th/U ratios,this age is considered to represent the crystallization time of the Dasi volcan-ism. The volcanic rocks in the Dasi,Majiashan and Lingxiang Formations share similar trace elementand REE partition patterns as well as Sr-Nd isotopic compositions. In combination with the regional geol-ogy,it is proposed that the southeast Hubei volcanic rocks were formed mainly during the Early Creta-ceous,just like other volcanic basins in middle-lower Yangtze valley. A lithospheric extension is also sug-gested for tectonic regime in this region in the Cre-taceous Period.     

Response of downstream sediment to water resource development in mainstream of the Lancang River

The impact of hydropower cascades of the Lancang River on downstream sedimentation has become one of the key problems in the research of the transboundary water resource development and its possible environmental effects. In this paper, the newest sediment data series spanning 17 years （1987-2003） at Yunjinghong hydrometric station and Chiang Saen hydrometric station, in northern Thailand, are analyzed to reveal these effects. Monthly mean sediment concentration data of the two stations are compared in-phase and yearly series are analyzed by the method of correlation and regression analysis and causality test. The analysis result shows that, though both of them are located at lower reaches of Manwan and Dachaoshan hydropower stations which are already constructed and in use, the sediment responses of the two stations are different under the regulation of the hydropower stations Annual series at Yunjinghong station are positively correlated but do not match well with those at Chiang Saen station. In addition, the results of Granger causality test on the time series also suggest that the series of maximum monthly mean sediment concentration of the Yunjinghong station each year may give cause for the ones of Chiang Saen station, while the series of minimum monthly mean sediment concentration each year and annual mean sediment concentration of Yunjinghong do not evidently give cause for the ones of the other station. Undoubtedly, this discovery will provide new evidences to assess the impacts of cascades construction in mainstream of the Lancang River on the variation of downstream sediment and its transboundary effects.     

岷江上游干旱河谷区土壤水分含量及其动态

于2002年8月～2003年7月对四川西部理县干旱河谷区土壤水分状况进行了定位研究。结果表明：在理县干旱河谷区，不饲海拔高度0～50cm土层土壤平均含水量总的变化趋势是阴坡比阳坡高。而土壤水分空间异质性阳坡比阴坡大。同一坡向不同海拔的土壤含水量变化为2050m处的最高，1850m处的次之，1450m处再次之，1650m处最少，表明了在干旱区河谷的两岸坡面上部土壤水分状况最好，在坡面下部靠近河流处次之，中下坡水分条件最差。相同海拔高度，不同坡向土壤含水量都表现为随着土层深度的增加土壤含水量增加的趋势，且30～50cm土层的土壤含水量最高。     

南京长江第三大桥斜拉索的防腐系统研究

根据目前我国拉索型桥梁索结构的防腐体系均遭到不同程度破坏的现状,在对索结构防腐体系破坏原因分析的基础上,结合南京长江第三大桥的特点,研究了拉索的防腐系统。结果表明:选择双峰HDPE护套,及在拉索内填充具有水汽隔绝、阻蚀防腐和润滑抗磨双重作用的防腐填充物,可延长拉索的使用寿命。该研究已成功应用于南京长江第三大桥的斜拉索体系。     

黄河微污染原水生物预处理研究

针对受污染的黄河水源水,进行生物陶粒滤池试验研究.结果表明,生物陶粒滤池预处理能全面净化受污染黄河水的水质.在气水比为0.25:1、滤速为5.1m/h的条件下,对CODMn、NH 4-N、NO-2-N、的去除率分别为4.8%-22.7%,20%-77.6%,75%-98.3%.对UV254和藻类的去除率分别为7.3%-30.4%和24.4%-41.8%.     

塔里木河流域遥感影像数据库系统的设计和建立

目的 采用当前非常流行的数据仓库技术管理塔里木河流域海量遥感影像、背景数据，实现塔河流域管理的数字化、信息化。方法 采用当前流行的数据仓库管理技术，按照空间数据-属性数据一体化、多源数据无缝集成及基于C／S结构和关系数据库3层体系结构的设计思想，将塔里木河流域遥感信息、空间地理信息、多专题信息、社会经济信息，以及多媒体和元数据等各类信息进行集成建库。结果 实现了多类型、多尺度的海量遥感影像、空间地理等基础数据的无缝集成和统一管理。结论 综合使用遥感、地理信息系统、数据库等技术，建立基于动态监测与管理的生态环境信息系统，具有明显的工程优势和技术优势。     

疏勒河流域中下游景观格局动态变化分析研究

1：10万土地利用现状图和地形图，对疏研究，结果表明：疏勒河流域中下游景观指数呈波形变化，1990～1994年，景观多样性指数和均匀度指数呈增加态势，1994～1999年呈减小态势，而景观优势度指数的变化态势与上述两个指数的变化态势相反．各景观要素的转化使疏勒河流域中下游的景观格局向两个不同方向发展：一方面在靠近水源和流域的中上游地带，农耕发达，一般形成集约化、灌溉系统完善的农田景观；另一方面，随上游水资源利用程度的不断提高，在远离水源或流域下游地带，天然生态体系破坏不断加剧，区域景观向荒漠化方向发展，说明流域中上游人工绿洲的形成与发展是以流域下游天然绿洲大面积荒漠化为代价的．     

引黄灌区地下水漏斗的综合治理--以位山灌区为例

位山黄灌区下游由于地表水资源不足,地下水强烈开采,已形成大面积的漏斗区.为了该区域水资源的持续利用,应对该区域水资源施行统一管理、地下水的合理调控、节约用水、防治水污染和建立地下水监测网络等措施.     

大珠江三角洲城市群经济整合机制与模式研究

基于经济全球化对大珠江三角洲城市群经济整合机制展开系统性的深入分析．从产业体系的升级和重组、产业空间转移和集群化发展对城市群经济整合发展深层作用等多维的视角出发提出大珠江三角洲城市群经济整合模式，其中包括产业转移与互补、点轴联网辐射、职能分工和集群化整合等4种模式。