两种干旱指标在乌海地区干旱分析中的应用比较研究

本文对降水量距平百分率、M 指数两种干旱指标进行了分析、比较,发现降水量距平百分率是适合乌海地区的干旱指标,并以此为乌海地区的干旱指标,根据乌海实际干旱情况,将干旱等级标准按不同时间尺度进行了调整,根据调整后的等级标准,对乌海地区的干旱情况进行了分析.     

开采沉陷工程岩体本构关系研究

传统开采沉陷理论存在对采动岩体本构关系研究不够的问题, 本文在运用现代工程地质学理论和现代数学力学理论相结合, 对采动岩体本构关系进行深入研究的基础上, 提出了用黑箱问题灰箱化的全息反分析法, 确定采动工程岩体本构关系及其有关参数。实例分析表明, 对于复杂岩体结构的开采沉陷问题, 能够取得满意的结果。     

Change of annual extreme water levels and correlation with river discharges in the middle-lower Yangtze River: Characteristics and possible affecting factors

As one of the fastest developing regions in China, the middle-lower Yangtze River(MLYR) is vulnerable to floods and droughts. With obtained time series of annual highest water level(HWL), annual lowest water level(LWL) and the corresponding river discharges from three gauging stations in MLYR that covering the period 1987–2011, the current study evaluated the change characteristics of annual extreme water levels and the correlation with river discharges by using the methods of trend test, Mann-Whitney-Pettitt(MWP) test and double mass analysis. Major result indicated a decreasing/increasing trend for annual HWL/LWL of all stations in MLYR during the study period. A change point in 1999 was identified for annual HWL at the Hankou and Datong stations. The year 2006 was found to be the critical year that the relationship between annual extreme water levels and river discharges changed in the MLYR. With contrast to annual LWL in MLYR, further investigation revealed that the change characteristics of annual HWL were highly consistent with regional precipitation in the Yangtze River Basin, while the linkage with Three Gorges Dam(TGD) operation is not strong. Our observation also pointed out that the effect of serious down cutting of the riverbed and the enlargement of the cross-section area during the initial period of TGD operation caused the downward trend of the relationship between annual LWL and river discharge. Whereas, the relatively raised river water level before the flood season due to TGD regulation since 2006 explained for the changing upward trend of the relationship between annual HWL and river discharge.     

Effect of bis(tributyltin) oxide on reproduction and population growth rate of calanoid copepod Schmackeria poplesia

A full life-cycle toxicity test, combined with histology, on calanoid copepod Schmackeria poplesia was used to study the effect of bis(tributyltin) oxide (TBTO). The results indicate no sex-specific differences in TBTO toxicity. Long-term mortalities of the copepods exposed to concentrations higher than 20 ng TBTO L⁻¹ were significantly elevated compared with that of control, and larval development was inhibited when they were exposed to 40 and 60 ng TBTO L⁻¹. The percentages of ovigerous females were reduced compared with the control (P<0.01) after 24 days exposure to concentrations higher than 10 ng TBTO L⁻¹. Histological examinations suggest that exposure to TBTO might block the posterior end of the diverticula and inhibits the production of egg sacs. A modified Euler-Lotka equation was used to calculate a population-level endpoint, the intrinsic rate of natural increase (r _m), from individual life-table endpoints, i.e. mortality rate, time of release of first brood, sex ratio, the fraction of ovigerous females among all females as well as the number of nauplii per ovigerous female. Apart from the highest TBTO concentration (60 ng L⁻¹), where all females aborted their egg sacs, 20 ng TBTO L⁻¹ was the only concentration that significantly decreased r _m compared with that of control (an effect associated with decreased sex ratio). The results show that the S. poplesia is affected by prolonged exposure to low concentrations of TBTO. The full life-cycle toxicity test combined with histology experiments provides more integral understanding of the toxicity of endocrine disrupters.     

鄱阳湖流域径流模型

流域径流是鄱阳湖主要来水,建立鄱阳湖流域径流模型对揭示湖泊水量平衡及其受流域自然和人类活动的影响具有重要意义.针对鄱阳湖-流域系统的特点:流域面积大(16.22×104km2)、多条入湖河流、湖滨区坡面入湖径流等,研究了相应的模拟方法,建立了考虑流域土壤属性和土地利用空间变化的鄱阳湖流域分布式径流模型.采用6个水文站1991-2001年的实测河道径流对模型进行了率定和验证.结果显示,模型整体模拟精度较高.其中,赣江、信江和饶河均取得了较好的模拟结果,月效率系数为0.82-0.95;抚河和修水模拟精度略低,为0.65-0.78.模型揭示了研究时段内年平均入湖径流总量为1623×108m3,其中,赣江最多,占47%,其次为信江和抚河,分别占13%和12%,湖滨区坡面入湖径流约占4%,其余24%来自饶河、修水以及其它入湖支流.模型将用于评估流域下垫面或气候变化引起的入湖水量变化,为湖泊水量平衡计算提供依据.     

Spatial and temporal variability of reference evapotranspiration and influenced meteorological factors in the Jialing River Basin,China

Theoretical and Applied Climatology - Reference evapotranspiration (ETr) is one of the important parameters in the hydrological cycle. The spatio-temporal variation of ETr and other meteorological...     

利用GPS对太阳耀斑进行监测及预报的方法研究

为利用GPS对太阳耀斑进行监测和预报研究,从IGS网站上下载了全球分布的60多个GPS跟踪站的观测数据,对两起X级的太阳耀斑爆发时所引起的TEC变化进行了计算及分析.结果表明,中低纬度的GPS跟踪站在太阳耀斑发生期间均监测到了总电子含量的突增现象,并且与X射线辐射通量图具有很好的一致性;差分TEC可以获得更精细的总电子含量的变化情况,更加适合于对太阳耀斑的细致研究;通过对相邻日绝对总电子含量的研究发现,在耀斑爆发前期,相邻日绝对总电子含量会出现大幅度的跳跃现象.     

长江中下游夏季降水变化与亚洲夏季风系统的关系

以长江中下游流域实测降水数据和亚洲季风指数为基础,采用Mann-Kendall检验、线性相关和偏相关分析、小波分析等方法,揭示长江中下游夏季降水的时空变化特征及其与亚洲季风系统之间的相互关系和影响差异。结果表明,近50 a来长江中下游夏季降水量呈显著的增加趋势,其与亚洲主要夏季风指数之间均呈负的线性相关关系,且显著性影响范围东亚夏季风大于南海夏季风大于南亚夏季风。不同亚洲夏季风子系统间存在复杂的相互作用关系,尤其是东亚夏季风和南海夏季风之间的相互作用对长江中下游夏季降水产生了重要影响。长江中下游夏季降水量与亚洲主要夏季风指数存在2~4 a时间尺度上的显著相关性,且以反位相关系为主。此外,长江中下游夏季降水量与东亚夏季风的相干性最为突出,在小于8 a的时间尺度上,两者之间的相关性在近50 a来呈现减弱的趋势,特别是自20世纪80年代中后期以来。     

基于GF-1卫星遥感影像的港口空间格局监测与评估——以营口鲅鱼圈港区为例

文章采用国产GF-1卫星遥感影像,通过对港口内部空间格局以及各组成单元特征进行分析,建立了面向对象的港口空间格局遥感监测方法与步骤,探索构建了码头岸线指数、码头岸线利用指数、码头指数、堆场指数和港池指数等港口空间格局集约利用评估指标,并以营口鲅鱼圈港区为例进行实证研究。结果显示:营口鲅鱼圈港区的码头岸线指数为0.51,码头岸线利用指数为1 498.16万t/km,码头指数为12.23hm~2/km,港池指数为242.76hm~2/km,堆场指数为108.46hm~2/km。码头岸线与码头面积、堆场面积、港池面积的基本比例为1.00∶12.00∶108.00∶250.00。营口鲅鱼圈港区仍有8 821.17万t/a的吞吐量提升空间。     

A Multi-Generation Schmakeriapoplesia Culturing System for Use in Ecotoxicological Study

Crustacean zooplankton form the keystone link between primary producers and fish stocks in marine and estuary, ecosystems. We have established a multi-generation cultivation system for zooplankton ruth which future experiments on the biological effects of pollutants in marine and estuary environments can be better performed. A population of calanoid copepod, Sehmakeria poplesia, was collected in December 2003 and maintained in a static system through all stages （eggs to adults）. The population ex- hinted an average developmental time of 13.6 d in conditions corresponding to the natural environment （water temperature 20~C salinity 15）. A series of experiments were performed to examine copepod egg production and hatching success as functions of food type and feeding concentration. Results in our study showed that Isoehrysis galbana was more favored for the reproduction of cope- pods than Phaeodactylum tricornutum, and 10xl0%ellsmL-1 was the most practical algae concentration. We have demonstrated that the Schmakeria poplesia population can be maintained in the laboratory through multiple generations. In addition, methods to control egg production through changes in food concentration have been established, making it feasible to control the start date of exposure experiments or the timing of the collection of oftspring to initiate a new generation.