用CEOF分析近百年中国东部旱涝的分布及其年际变化特征

通过1850～1991年旱涝百分率的CEOF分析，研究了近百年来中国东部旱涝的分布特征、时空变化特点及年际演变规律。结果表明，我国东部主要有三种旱涝分布类型。第一种类型是以长江流域为中心全国大范围旱或涝，空间位相近似相同，且有10.7年和3.1年周期性变化，振幅强度在1923～1924年间曾发生过增强突变。第二种类型为南北旱涝趋势相反的分布，空间位相自北向南变化显著，且有4.3年周期性变化，振幅强度在1884～1885年间曾有一次减弱突变。第三种类型呈江淮流域与华北和华南旱涝趋势相反的分布，空间位相从南北两个方向向中间或相反方向移动，并有3.4年周期性变化，振幅强度在1911～1912年有过增强突变。     

北京西山南部构造序列初探

笔者利用解析构造学方法,初步确定了本区的构造序列。它反映了从下部构造层次到上部构造层次的系统变化,从早期的层内固态流变经压扁作用和弯曲作用到后期的剪切破裂变形过程中岩石韧性递减的系统演变。由于岩浆侵入而使其间增加了一个韧性再增强的变形期。     

Pedogenic zones in postglacial sediment of lake manitoba,Canada

The postglacial sediment record of Lake Manitoba is composed dominantly of silty clay to clayey silt with little variation in most physical, chemical, and mineralogical properties. Distinct in the sedimentary sequence of this large lake, however, are four zones that have a low moisture content, blocky to pelletal structure, and gleyed colour. All of these zones formed during the warmest and driest postglacial period in the region, 9500 to 4500 years ago. Although several possible hypotheses can be formulated regarding the origin of these zones including changes in sedimentation rate, clay mineralogy, lake chemistry, and depth of winter freezing, the most likely explanation is that they represent pedogenic horizons. Formation by pedogenesis during dry or extremely low water conditions is not mutually exclusive of the other hypotheses, and several are favoured by low water conditions.     

A three‐component end‐member analysis of streamwater hydrochemistry in a small Japanese forested headwater catchment

Intensive water sampling in conjunction with hydrological observations was conducted during three different rainstorms in order to understand the effects of rainfall events on the temporal variation of streamwater chemistry in a small headwater forest catchment. Concentrations of Na⁺ and SO₄^2? decreased as the discharge rate increased. Hydrograph separation of the components was made using the three‐component model based on the end‐members mixing analysis (EMMA). The three end‐members were:

• 1 the groundwater in the saturated zone that prescribes the chemistry of the baseflow;
• 2 the throughfall that dilutes the streamwater;
• 3 the groundwater in the transient saturated zone prescribed, which was dependent on the groundwater level.

When the groundwater level was lower, only the two components, groundwater in the saturated zone and throughfall, affected the streamwater chemistry. When the groundwater level rose and the saturated zone spread, the groundwater in the transient saturated zone became the third component. When the groundwater in the transient saturated zone contributed to the discharge, this component became the dominant source and the streamwater chemistry was affected by the groundwater chemistry in the transient saturated zone. When this component was discharged as the saturation overland flow, the streamwater chemistry was greatly affected by this component. Copyright © 2001 John Wiley & Sons, Ltd.     

EUTROPHICATION AND RED TIDES AS CONSEQUENCES OF ECONOMIC DEVELOPMENT

1 mTRoorcnoxThe EnvirDment AgenCy of UK (l997) defins eUtIDPhication as "the enrichInnt of waters byinorgedc plant nUtrientS that result in the simulation of an mp Of syInPtOInati changes. These includethe inCrased PrOduCtiOn Of aigae or othe aquatic PlantS, affeChng the quallty of the water and distUIbingthe balance Of orpedsms Present within it. Such changes Inay be undesirable and intetw with wateuses." Sndth et al. (l999) indicated tha eopation of waters is mainly caused by h…     

地下水物理参量强地震中短期预报方法的检验

应用“九五”子专题“地下水物理参量异常识别标志体系及预报方法研究”的研究思路,预报方法和指标对河北省井网1983年以来的水位观测资料进行了全时程扫描,结果表明“群井群常年频次法”在河北及邻近地区中强地震前有较明显的异常显示,应用效果较好,对该方法进行了预报效能R值评分,评价结果表明漏报率低,虚报率高。     

Chironomids as indicators of climate change: a 100‐lake training set from a subarctic region of northern Sweden (Lapland)

Multivariate numerical analyses (DCA, CCA) were used to study the distribution of chironomids from surface sediments of 100 lakes spanning broad ecoclimatic conditions in northern Swedish Lapland. The study sites range from boreal forest to alpine tundra and are located in a region of relatively low human impact. Of the 19 environmental variables measured, ordination by CCA identified mean July air temperature as one of the most significant variables explaining the distribution and the abundance of chironomids. Lossonignition (LOI), maximum lake depth and mean January air temperature also accounted for significant variation in chironomid assemblages. A quantitative transfer function was created to estimate mean July air temperature from sedimentary chironomid assemblages using weightedaveraging partial least squares regression (WAPLS). The coefficient of determination was relatively high (r² = 0.65) with root mean squared error of prediction (RMSEP, based on jack-knifing) of 1.13 °C and maximum bias of 2.1 °C, indicating that chironomids can provide useful quantitative estimates of past changes in mean July air temperature. The paper focuses mainly on the relationship between chironomid composition and July air temperature, but the relationship to LOI and depth are also discussed.     

A study on environmental aridity over northern and southern to Qinling Mountains under climate warming

1 Introduction With progressive researches on global climate change, an integrated study of various disciplines tends to be inevitable. Mr. Moore III, chairman of IGBP, holds that the key to integration is to synthesize scientific findings so as to get new ideas and to chance cognition up to a new high[1]. Micro-study, rather than macro-study focuses on regional change[2-5]. To strengthen the global perspective in the study, "to research on typical regions and to deepen the regional divide…     

新疆新源台固体潮潮汐因子特征浅析

采用Venedikov调和分析方法对新源台倾斜固体潮整点观测数据进行处理，得到倾斜固体潮鸩波潮汐因子变化曲线。分析其震兆异常特征，给出了新源台倾斜固体潮潮汐因子异常标准，结果发现异常与周围200km范围内的5级以上地震对应较好，具有较高的预报效能并通过了尺值评分检验。     

2004年12月26日印尼大地震河北省数字水位、地热记震能力分析

分析了我省地震监测井网数字化水位、地热资料对2004年12月26日印尼大地震的震后反映,分析了水位、地热对地震波反映的表现形态.通过分析可验证我省2001年新上数字资料-水位和地热的可靠性、灵敏性,以便科学地分析数字水位、地热资料、提取可靠的前兆异常信息,高效地服务于日常地震分析预报工作.