Pore-water response on seasonal environmental changes in intertidal sediments of the Weser Estuary,Germany

In order to determine time-dependent changes in estuarine pore-water chemistry and flux variations across the sediment-water interface, sediment cores of an intertidal mud flat in the Weser Estuary were taken monthly over a one-year period. Sediment temperature, pH, Eh, Cl^–, O₂, NO ₃ ^– , and SO ₄ ^2– pore-water concentrations were measured and showed variations that relate to the changes of surface temperature and estuarine water composition. Fick's first law was applied to quantify diffusive fluxes from concentration gradients in the diffusive boundary layer and in the pore water. Total nitrate fluxes were calculated from flux chamber experiments. Diffusive oxygen fluxes increased from 5 mmol m^–2 d^–1 in winter to 18 mmol m^–2 d^–1 in early summer, while nitrate fluxes into the sediment increased from 3 mmol m^–2 d^–1 in winter to 60 mmol m^–2 d^–1 in early summer. Oxygen and nitrate fluxes into the sediment correlated linearly to sediment temperature. Sulfate fluxes increased from 0.5 mmol m^–2 d^–1 in winter to 10 mmol m^–2 d^–1 in August and September. Converted into carbon fluxes, the sum of these oxidants ranged from 10 mmol m^–2 d^–1 in winter to 80 mmol m^–2 d^–1 in summer. An estimation of the upper limit of the annual nitrate flux into the sediment showed that about 10% of the 250,000 t of nitrate discharged annually by the river may be decomposed within the inner Weser Estuary.     

湖相沉积物与全球变化的研究

为预测未来全球的气候变化，必须了解在过去水圈、气圈与生物圈的各自作用以及它们是如何相互影响的。为此，ＩＧＢＰ（国际地圈－生物圈计划）组织了过去全球变化项目（ＰＡＧＥＳ）。湖相沉积物保存着与ＰＡＧＥＳ有关的不同时空尺度的丰富的地球系统历史信息，特别是湖相沉积物包含着可以说明全球气候变化的水圈与生物圈的陆源组分的反应。这种信息对了解影响气候变化的流域是如何发展的至关重要。笔者应用西伯利亚贝加尔湖与中国西北部青海湖作为两个实例，叙述了多学科研究湖相沉积物物理与化学参数，并利用这些参数测定了晚更新世湖区及其流域对过去气圈的变化以及日幅射分布的影响     

地球内核快速旋转的发现与全球变化的轨道效应

科里奥利效应是产生内核快速旋转的主要原因。科氏力使上升物质向西漂移，下降物质向东漂移；造成地球外层自转减速，地球内层自转加速。所以，自旋体中的垂直运动可以产生大规模的水平运动——圈层差异旋转。地震波测量结果表明，内核旋转速度每年比地壳地幔快１°。对于一个内核差异旋转的地球，太阳辐射不仅形成地磁场的内外磁尾和地壳与内核的反向振动，而且影响核幔角动量交换和电磁耦合，从而控制了地球内能的释放，形成天文周期与地质旋回的一一对应关系。地球轨道和太阳轨道的全球变化响应，为太阳辐射量变化控制地球内能释放提供了证据     

Influence of water level fluctuation on the spatial dynamic of the water chemistry at Lake Fertõ/Neusiedler See

Lake Fertõ/Neusiedler See is a steppe lake situated on the Hungarian-Austrian border with a surface area of 309 km². It is an extremely shallow lake with regulated outflow. 54% of the whole lake and 85% of the Hungarian part (75 km²) is covered by reed. There are numerous reedless areas (inner ponds) of variable size within the reed belt, which is enmeshed with canals connecting the inner ponds with the open water areas. Fundamental differences were recorded in the water chemistry of the three water type areas, open water, canals and inner ponds. The degree of these differences is basically determined by the distance from the open water areas and the water level of the actual years. An extremely high, an average and an extremely low water level year was examined, in order to present the spatial and temporal differences in the water chemistry of the investigated water bodies. Differences due to the water level fluctuation between years in the three different water types are discussed on the basis of electrical conductivity, cation, and anion concentration changes of the water. Our results support the concept of high instability of Lake Fertõ and describe habitats with remarkable temporal and spatial variability. The high influence of water level on habitat conditions at different sites of the lake recommend a carefull water level regulation strategy.     

长江三角洲主要城市产业结构转换的综合评价

文章在对地区产业结构转换影响因素系统分析的基础上，采用定量分析方法，对长江三角洲15个主要城市的产业结构转换能力、产业转换速度、产业转换方向以及它们之间的关系进行探讨。研究表明：长江三角洲主要城市产业结构转换能力的区域差异明显，产业结构转换能力与区域经济发展所处阶段有很大的关系；产业结构转换能力、速度与经济发展水平呈正相关。     

中国大陆地区中强地震前加卸载响应比异常时间尺度的统计研究

加卸载响应比理论是近年来提出的地震预测方法。本文进行了加卸载响应比异常时间尺度的统计研究，其中包括中国大陆地区5．0～8．1级的部分中强地震共30个震例，并得出加卸载响应比异常的时间尺度与未来地震震级之间的拟合函数。结果表明，地震前加卸载响应比异常的时间尺度与未来地震的震级具有正变关系，即震级越高，地震前加卸载响应比异常的时间尺度越长。根据加卸载响应比异常的时间尺度与震级之间的关系可以估计未来地震的发震时间，同时，可以确定加卸载响应比时空扫描过程中时问长度的大小。     

A simulation model of morphological,vegetation and sediment changes in ephemeral streams

A model to simulate channel changes in ephemeral river channels and to test the effects of hydrological changes due to climate change and[sol ]or land use change was developed under the auspices of the EU funded MEDALUS programme (Mediterranean Desertification and Land Use). The model, CHANGISM (Channel Change GIS Simulation Model), is designed to simulate the effect of channel flow events and of climate conditions on morphology, sediment and vegetation, through sequences of events and conditions, over periods of up to several decades. The modelling is based on cellular automata but with calculations for water and sediment continuity. Process rules have both deterministic and stochastic elements. An important feature of the model is that it incorporates feedback elements between each event. The main aim of the model is to indicate the likely outcomes of events and combinations of conditions. It is linked to GIS for both input and output. The modelling is based on a channel reach and state is input as GIS layers of morphology (DEM), sediment and vegetation cover and state. Other initial conditions of soil moisture, groundwater level, and overall gradient are input. Parameters for processes are read from tables and can be easily changed for successive runs of the model. The bases for decisions on process specifications are discussed in this paper. Initial tests of the operation and sensitivity of the model were made on idealized reaches. The model was then tested using data from monitored sites in SE Spain. Simulations using clearwater flow worked well but initial simulations using events with sediment loads showed some tendency for excess deposition. Further tests and modifications are taking place. Overall, the model is one of the most sophisticated that simulates the interaction of flows with sediment and vegetation and the outcomes in terms of erosion, deposition, morphology, sediment cover, vegetation cover and plant survival over periods of up to 30 years for the scale of a channel reach. Copyright © 2005 John Wiley & Sons, Ltd.     

洱海环境演变与大理城市发展的关系研究

针对洱海特殊的生态环境和对大理城市发展所起的举足轻重的作用，2002年通过实地环境调查和系列历史及动态资料分析进行了洱海和大理城市之问人地关系的互动研究。概括出大理城市发展的5个阶段，结果表明人类生存场所发展的总趋势是从高处往低处下移，从山前台地向下迁往山缘冲积洪积扇平原，直至湖滨平原地带。并着重分析了变迁的原因和人类活动的影响状况，从而使人们在开发利用洱海的同时，促进人类活动和城市发展建设相得益彰，并建议选择旅游和供水为主的和谐可持续发展道路，强化政府的宏观管理，增大科技投入。     

近40年来珠江口的海平面变化

利用大万山附近1°×1°经纬度网格的卫星高度计资料(1993—2006),计算出珠江口绝对海平面的上升速率为0·30±0·05cm/a,与由卫星高度计得出的全球平均海平面的上升速率一致。珠江口各验潮站近40年的潮位变化趋势分析表明,珠江口海平面正加速上升,为全球气候变暖所致;珠江口海平面与全球温度变化和ENSO活动密切相关,一般在ENSO年海平面相对较低。以IPCC有关全球温度上升幅度的预报值和海平面与全球温度变化的关系为依据,预计到2030和2050年珠江口绝对海平面将分别上升6～14和9～21cm,若考虑地面沉降以及波动值,珠江口部分岸段相对海平面将可能分别上升30和50cm。     

2000—2019年鄱阳湖生态经济区水源涵养时空变化

水源涵养是生态保护的一个重要方面,对鄱阳湖生态经济区生态保护具有重要意义。本文基于InVEST模型,对鄱阳湖生态经济区2000—2019年产水和水源涵养时空变化进行了分析,并运用空间自相关探究了高程、坡度与水源涵养功能的空间关系。结果表明:①鄱阳湖生态经济区多年平均产水深度为971.04 mm,多年平均水源涵养深度为299.298 mm;②2000—2019年水源涵养深度先上升后下降,变化幅度较大,整体呈上升趋势;③水源涵养功能呈地域分布,重要区和极为重要区主要分布在东部和西北部林地,一般重要区分布在鄱阳湖平原;④水源涵养与高程和坡度呈正相关,高值多出现在高海拔和坡度较大的地区。