Combining forms of heavy metal elements in Dianshan Lake sediments and their spatial and temporal variations     

Leping ZHENG Yuliang LIU Xiaoyan SHI Xianwen QIAN Lihua ZHOU Xiaoyan LIU Xinxin WU Weimin SUN 《中国地球化学学报》2006,25(B08):143-143

Dianshan Lake is one of the important water supply sources for Shanghai City. The contents of heavy metals in the sediments are obviously higher than those in the overlying water body. The contents of Pb in the sediments vary seasonally; with increasing depth, the contents of Cd, Pb, Cu, Cr and Fe show no variation generally, but Mn varies in the peak pattern. Cd, Pb, Cu, Cr and Fe in the sediments are present predominantly in sludge phase, but iron and manganese oxide form of Pb and organic matter-sulfide form of Cu are their respective preferential combining forms. Manganese is present largely in exchangeable form, iron-manganese oxide combined form and sludge form. The contents of the various forms of Cd, Pb, Cu, Cr and Fe tend to vary with changing season and depth. The contents of exchangeable forms of Fe and Mn vary with depth in the peak-like pattern.  相似文献   

Mercury levels in surface waters of six reservoirs in the Wujiang River     

《中国地球化学学报》2006,25(B08):151-151

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Seasonal variations of adsorption/desorption equilibrium concentrations of P at water-sediment interface in the Meiliang Bay, Taihu Lake, China     

Xia JIANG Xiangcan JIN Dongmei LIU 《中国地球化学学报》2006,25(B08):164-165

Seasonal variations of adsorption/desorption equilibrium were investigated by collecting overlying water and seasonal sediment from the Meiliang Bay, Taihu Lake, China. At the same time, seasonal variations of TP and P fractions＇ concentrations in the initial and end of adsorption experiment were also carried out. In addition, the effects of temperature on the P translocation process were also conducted and discussed. The following conclusions were obtained： The sequence of adsorption/desorption equilibrium concentrations of P at water-sediment interface was spring〈winter〈autumn. In sediment the concentrations of TP decline. Concentration P decreased with temperature.  相似文献   

Hydrologic and hydraulic characteristics of the Yellow River and impact of flow and sediment diversion     

Dong WANG Shaoming PAN Jichun WU Qingping ZHU Chang LIU 《中国地球化学学报》2006,25(B08):168-169

In the history, the Yellow River nurtured Chinese civilization. It is respected as the ＂ancestor of the four large rivers in China＂ and praised as ＂the mother river of China＂. At the same time, the Yellow River is regarded as ＂the misery of China＂ and considered as the most complex river hard to control in the world. Today, the Yellow River is also one large river greatly influenced by human activities in the world. The safety of the Yellow River, particularly flood control, is always the most important issue for governing and developing the country. Great achievements have been made after many years of efforts for controlling the Yellow River. However, since the nineties of 20 century, some new problems occurred, such as sharp reduction of flux to sea, dry rivercourse, worsen environment, etc. Rapidly shrinking riverbed and two-level perched stream are disadvantageous to flood safety especially. The new concepts and new practices are urgently needed to control the river. Therefore, the Yellow River Conservancy Committee of Ministry of Water Resources had continuously carded out flow and sediment diversion each year from 2002 to 2005. To timely probe into the new issues produced after flow and sediment diversion, and in order to deepen the understanding of rules for the Yellow River＇s water and sediment and provide reference and experience to the researchers for other large rivers, five hydrologic and hydraulic characteristics of the Yellow River, such as lack of water, much of sediment, different resources of water and sediment, inconsistency between water and sediment and frequency of sink switching and route changing, are described. Flow and sediment diversion of the Yellow River is also reviewed. Under flow and sediment diversion,  相似文献   

赴埃及访问总结     

《气象科技合作动态》2006,(4):5-15

为了加强国家级培训中心的能力建设和国际培训与交流，提高培训水平，拓展培训领域，加强管理和师资队伍建设，学习其他国家先进气象水文教育培训的经验，经中国气象局批准，并应埃及气象局局长董事会（Board of Directors）代理主席Magdy Ahmed Abbas的邀请，以中国气象局培训中心副主任刘国平为团长，人事处处长李洪臣、教育科研处副处长赵庆生、科技培训部主任俞小鼎、  相似文献   

科技之窗     

《水文》2006,26(6):95-95

本期“科技之窗”栏目,主要介绍中国水利学会2006学术年会和2006年度大禹水利科技奖水文水资源和信息化类获奖项目统计信息；同时简介了中国水利学会水文专业委员会承办的水文分会场有关情况。  相似文献   

区域气候模式(RegCM2)与水文模式耦合的数值试验   总被引：12，自引：2，他引：12  

张红平  周锁铨  薛根元  孙琪 《南京气象学院学报》2006,29(2):158-165

建立不均匀的地表径流算法，修改RegCM2的径流方案，设计了一个适合与气候模式RegCM2耦合、能模拟水文站流量的汇流模式，模拟了1998年6、7、8月降水的空间分布，分析了该径流方案对降水、地表热量通量、地表径流、土壤湿度产生的影响。结果表明：（1）该方案在模拟1998年长江流域降水空间分布上有一定的合理性，在一定程度上改善了降水量的模拟，其影响大致是总降水量的10％；（2）地表径流方案改变了地面向大气输送的热量通量，这种作用随时间发生变化，这种变化与地表水分的再分配有关；（3）本方案计算的土壤渗透率较强，在暴雨初期，产生径流较少，而在暴雨后期土壤湿度增大，产生的地表径流较大，这一点更符合洪水形成的特点；（4）水文一气候耦合模式模拟了两个长江水文站的流量，模拟值基本反映了实测值的变化趋势，也表明耦合模式基本能反映1998年夏季长江流域大暴雨期间的地表水文过程。  相似文献   

中国西北地区的干旱与旱灾——变化趋势与对策   总被引：16，自引：1，他引：16  

程国栋  王根绪 《地学前缘》2006,13(1):3-14

干旱与水资源短缺是西北地区的基本环境特征。西北地区在气候变暖的背景下,区域降水量出现了明显的区域差异:西北西部的新疆地区,20世纪80年代以来降水量增加;西北东部大部分地区降水量持续减少,干旱、连旱趋势增加;黄河流域西北区域降水量减少,干旱化趋势最为显著。在气候干旱化增强的背景下,新疆地区总体上经过70年代的枯水期后,在80年代中期开始较大范围内径流量呈现增加趋势;河西东部、西北东部的黄河流域等地区,70年代以来径流持续减少,大部分河流枯水频率在78%以上,水文干旱化趋势显著。水资源的开发利用、水土保持以及土地利用等人类活动使得西北地区水文干旱进一步加剧。干旱是西北地区最为严重的自然灾害之一,受干旱化气候和水文变化趋势的影响,黄河流域和内陆流域干旱灾害不断加剧,近50a干旱灾害受灾面积急剧扩张,旱灾造成的农业粮食损失不断增加。从创新水资源开发利用途径与管理等角度,提出了提高气候变化的地区适应性和区域水-经济系统旱灾抵御能力的对策与建议。  相似文献   

北京军区给水工程团     

《中国勘察设计》2006,(7):22-23

北京军区给水工程团（Water Supply and Engineering Regiment of Beijing Military Area）组建于1974年，是集水文地质勘察与凿井施工于一体的国家甲级工程勘察单位。拥有目前国内最先进的水文地质钻探设备、凿井设备及各种物探找水仪器，固定资产总值1．3亿元。先后有100余人到北美、欧洲、西亚等地区考察和技术培训，掌握了世界上最先进的水井钻探和物探找水技术。主要业务范围包括水文地质勘察、地下水资源开发与评价、凿井工程、物探找水、物探测井及水质化验等。  相似文献   

编制地壳垂直运动速率等值线图的有限元法   总被引：5，自引：2，他引：3  

李家权  张勤 《地壳形变与地震》1998,18(3):57-61

根据地壳垂直运动研究中的均衡理论,建立描述地壳垂直运动速率空间分布的数学模型,并提出应用有限元法拟合地壳垂直运动速率面的理论和方法。通过计算验证,说明有限元法可实现对地壳垂直运动速率面的精确逼近,是编制地壳垂直运动速率等值图的有效方法。  相似文献