利用泥质岩硼含量重建过去湖泊古盐度和湖面变化历史

根据封闭湖泊古盐度与湖面变化之间具有反向变化的特点,以沱沱河地区通天河剖面为例,利用泥质岩的硼元素含量作为古盐度计,重建了青藏高原北部地区晚渐新世-早中新世湖泊沉积的古盐度变化曲线,讨论了应用湖水古盐度变化曲线追踪过去湖平面变化历史的适用范围和局限.结果表明:雅西错组上部古湖泊水体的盐度一般处于咸水湖分布区,盐度变化于微咸水到超咸水范围内,指示渐新世晚期气候干燥,湖平面长期处于低水位期;但中新世早期五道梁组沉积期,高原气候开始向湿润方向发展,湖水古盐度明显下降,湖水位快速上升.     

青海湖近600年的水位变化

根据王苏民＾「４」给出的青海湖深水区重力岩芯的密集采样结果,重建了青胡近６００年的水位变化,发现水位变化与降水关系密切,水位的长降时段与降水的丰枯时段相对应,６００年来青海湖区的环境变化有１８０年左右的周期。     

大空间建筑物室内气流的大涡模拟

利用大涡模式对大空间建筑物室内气流进行模拟研究,并取得了良好的效果。模拟的内容包括:(1)在机械通风情况下,当存储货物的仓库发生火灾时,将会改变室内的温度场和流场的分布;(2)在自然通风情况下,简单方形钝体建筑物以及大型体育馆室内的流场状况。对以上模拟结果的分析表明,发生火灾时,室内流场主要是由热力作用支配,通风口的位置、通风气流的热力性质、室内物品的堆放方式以及室内物品的热力属性都会在很大程度上影响室内的流场和温度场。在自然通风情况下,室外的气流状况和通风口的位置对室内的气流都有很大的影响,室外的风速大小和风向分别对室内风速的大小和流场分布有重要影响,而通风口的位置主要影响室内气流分布状况。由于决定室内气流的因素很多,所以像体育馆这种对室内气流和空气质量要求比较高的建筑物,要评价以及设计其通风效果及室内空气品质必须针对具体情况从多个方面作具体分析。     

One‐dimensional expression to calculate specific yield for shallow groundwater systems with microrelief

Although the importance to account for microrelief in the calculation of specific yields for shallow groundwater systems is well recognized, the microrelief influence is often treated very simplified, which can cause considerable errors. We provide a general one‐dimensional expression that correctly represents the effect of a microrelief on the total specific yield that is composed of the soil and surface specific yield. The one‐dimensional expression can be applied for different soil hydraulic parameterizations and soil surface elevation frequency distributions. Applying different van Genuchten parameters and a simple linear microrelief model, we demonstrate that the specific yield is influenced by the microrelief not only when surface storage directly contributes to specific yield by (partial) inundation but also when water levels are lower than the minimum surface elevation. Compared with a simplified representation of the soil specific yield, in which a mean soil surface is assumed for the calculation of soil specific yield, the correct representation can lead to lower as well as higher soil specific yields depending on the specific interaction of the soil water retention characteristics and the microrelief. The new equation can be used to obtain more accurate evapotranspiration estimates from water level fluctuations and to account for the effect of microtopographic subgrid variability on simulated water levels of spatially distributed hydrological models. Copyright © 2015 The Authors Hydrological Processes Published by John Wiley & Sons Ltd     

非饱和-非稳定渗流条件下的边坡临界滑动场

受季节性降雨或水库运行的影响,岸坡外水位及坡内孔隙水压力场的变化较大,不利于岸坡的稳定性。在水位变化过程中,利用非饱和-非稳定渗流有限元计算得到孔隙水压力场,基于非饱和土的渗流和抗剪强度理论,对水位变化过程中的边坡临界滑动场法进行改进,提出可考虑水位变化与岸坡非饱和-非稳定渗流过程的边坡临界滑动场数值模拟方法。将改进后的水位变化过程中的边坡临界滑动场法分别应用于黏土、粉土岸坡在水位升降过程中的稳定性分析,研究了水位升降速率及基质吸力对岸坡稳定性的影响,并揭示了边坡在水位变化过程中的稳定性变化历程。研究表明,该方法计算结果合理、可靠,更适用于涉水边坡的稳定性计算,且岸坡稳定性变化历程受水位升降速率、基质吸力等多种因素共同影响,只有在考虑非稳定渗流的基础上同时考虑基质吸力的作用才能正确得出水位变化过程中岸坡稳定性变化规律和实质。     

Stochastic systems with cross-correlated Gaussian white noises

This paper theoretically investigates three stochastic systems with cross-correlation Gaussian white noises. Both steady state properties of the stochastic nonlinear systems and the nonequilibrium transitions induced by the cross-correlated noises are studied. The stationary solutions of the Fokker-Planck equation for three specific examples are analysed. It is shown explicitly that the cross-correlation of white noises can induce nonequilibrium transitions.     

Effects of Salinity Fluctuation Frequency on the Osmolarity, Na^＋-K^＋ -ATPase Activity and HSP70 Expression in Juvenile Chinese Shrimp, Fenneropenaeus chinensis

Experiments were conducted to examine the effects of salinity fluctuation frequency on the osmolarity, Na+-K+-ATPase activity and HSP70 of Chinese shrimp Fenneropenaeus chinensis with initial wet body weight of 1.460 g ± 0.091 g. The salinity in the control group (D0) was 28 throughout the experiment, whereas treatments D2, D4, D6 and D8 were subjected to different salinity fluctuation frequencies of 2, 4, 6 and 8 d, respectively. The salinity in treatments D2, D4, D6 and D8 was kept at 28 for 2, 4, 6 and 8...     

新疆艾比湖湖面波动特征及其原因

艾比湖为西北内陆封闭湖泊,湖泊面积变化反映了区域气候环境的变化。通过艾比湖历史时期及近期湖面波动特征研究,对近期湖泊的演化趋势进行了分析。研究认为,近50年来艾比湖湖面经历了两次大幅度变化,20世纪60年代湖泊面积的大幅度萎缩与21世纪初湖泊面积的大范围扩张。近期艾比湖湖面扩展与流域降水增加密切相关,而20世纪60年代湖泊面积的萎缩主要受流域农业灌溉耗水等人类活动的影响。从气候历史演化的角度(没有人类活动作用)分析,类似目前的气候条件,艾比湖湖面以较稳定地保持在1000～1500km^2内较为客观。     

胶州湾叶绿素的浓度、分布特征及其周年变化

2003年6月-2004年5月对胶州湾及邻近海域水体中叶绿素a浓度变化及其空间分布进行了周年调查.结果表明,调查海域叶绿素a全年平均浓度为2.81mg/m^3,月平均浓度变化范围为0.73-8.44 mg/m^3.整个海域叶绿素a浓度周年变化呈现双峰型,分别在夏季8月和冬季2月出现两个高峰,但是不同区域的变化幅度不同,其水平分布格局为湾内高于湾外,湾内北部高于南部.营养盐浓度变化与叶绿素a浓度的变动未发现明显的相关性,但是在局部海域硅酸盐对冬季浮游植物水华的进一步发展具有一定的限制作用.综合分析营养盐、叶绿素a和浮游动物的周年变化及其之间的关系显示,下行控制（Top-down control）在胶州湾浮游植物的数量变动中起着重要的调控作用.     

Fluctuation in <Emphasis Type="Italic">Ommastrephe bartrami</Emphasis> yield in the North Pacific

The fluctuation in Ommastrephe bartrami yield from 1995 to 2001 in the North Pacific was shown obvious, on which this study was conducted using data of sea surface temperature (SST), chlorophyll-a (chl-a) and statistical production. The study shows that, cool water and low food abundance caused by abnormal Kuroshio resulted in the reduction in abundance of O. bartrami, which was worsened by excessive catch and the unawareness to local fishery resources protection. Supported by National Key Project for Basic Research of China (2005CB422300)