渭河天水峡谷全新世特大洪水水文学研究

古洪水水文学是全球变化科学领域的新兴学科.通过对渭河上游天水段基岩峡谷的详细考察,对在杜家坪村附近发现的全新世古洪水滞流沉积剖面进行了深入研究.沉积学观察和分析结果表明这些沉积物为洪水悬移质泥沙沉积形成,因而其主要成分为粉沙,分选良好.其磁化率值很低,表明它们是全新世晚期的沉积物,还没有受到风化成壤作用的改造.通过与其下游宝鸡峡全新世古洪水沉积剖面的地层学和考古年代学对比,确定其发生的时代在3200～3000a BP之间,即全新世大暖期结束之时.利用古洪水水文学方法,求出该组古洪水沉积层所记录的特大洪水的洪峰流量介于23460～25480m3/s之间.同时,通过进一步分析验证,表明对于古洪水洪峰流量计算结果是可靠的.本研究获得了渭河万年尺度特大洪水的水文学数据,延长了洪水水文数据序列,在工程水文领域有重要应用性价值,对于揭示全球变化的水文响应具有重要的科学意义.     

中国城市化对资源与环境影响的综合评价(英文)

This paper constructs a comprehensive evaluation index system for the urbanization level in China in terms of four aspects of urbanization connotation:population,economy,society,and land. A comprehensive measurement is carried out for the Chinese urbanization between 1981 and 2006 based on the Entropy method. The results show that the comprehensive level of urbanization in China has a continuous increase with the major features of economic growth and a rapid evolution of the geographical landscape,followed ...     

太湖水体后向散射特性模拟

为研究太湖水体后向散射系数的光学特性,利用太湖实测数据和半分析方法与光学闭合(Optical Closure)原理,对太湖水体的后向散射系数进行模拟,在此基础上对其光学特性和影响因子进行分析.研究结果表明:由于悬浮物浓度的差异,使得太湖水体后向散射系数具有明显的差异性,后向散射主要由无机悬浮物引起,浮游藻类对后向散射系数的贡献较小;由于悬浮物来源不同,使得悬浮物粒径分布、形状以及组成成分不同,导致太湖水体单位后向散射系数存在一定变化;以550 nm作为参考波段对太湖后向散射系数进行参数化,得出该波段后向散射系数与悬浮物浓度具有很好的线性关系,其指数在1.32~2.8之间变化,平均值为2.09.     

Modeling transient and long-term postseis-mic deformation: A case study of 1995 M_w9.5 Chile earthquake

In this paper, we firstly use finite element method (FEM) with Burgers model to simulate the postseismic viscoe-lastic relaxation taking 1960 Chile earthquake as an example. The postseismic deformation modeled with Burgers model includes co-seismic deformation, transient postseismic deformation and long-term postseismic deformation. So if we apply Burgers model to calculate postseismic deformation of 1960 Chile earthquake, there is no discrep-ancy phenomenon due to different durations of postseismic deforma...     

Application of the HY-1 satellite to sea ice monitoring and forecasting

The HY-1A satellite is the first oceanic satellite of China. During the winter of 2002-2003, the data of the HY-1A were applied to the sea ice monitoring and forecasting for the Bohai Sea of China for the fhst time. The sea ice retrieval system of the HY-1A has been constructed. It receives 1B data from the satellite, outputs sea ice images and provides digital products of ice concentration, ice thickness and ice edge, which can be used as important information for sea ice monitoring and the initial fields of the numeric sea ice forecast and as one of the reference data for the sea ice forecasting verification. The sea ice retrieval system of the satellite is described, including its processes, methods and parameters. The retrieving results and their application to the sea ice monitoring and forecasting for the Bohai Sea are also discussed.     

人工鱼礁区三种习见肉食性软体动物营养生态位研究

以小黑山岛人工鱼礁区为研究区,利用稳定同位素技术分析该海域三种习见肉食性软体动物长蛸（Octopus minor）、短蛸（Octopus fangsiao）和脉红螺（Papana venosa）的营养生态位,进而判断物种种间关系。分析结果显示：食物来源范围由大到小依次为长蛸、脉红螺、短蛸,其中长蛸食物来源包含短蛸食物来源范围,但脉红螺与两种蛸类食物来源无交叉;营养级由高到低依次为长蛸、短蛸、脉红螺。长蛸与短蛸营养生态位重叠比例较高,存在明显的竞争关系,与短蛸相比,长蛸营养级更高,食物来源范围更广,在竞争中处于优势地位;脉红螺的营养生态位与两种蛸类无重叠,其营养级比两种蛸类更低且无捕食或竞争关系。     

柴达木盆地东部地区不整合与油气成藏的关系

本文论述了柴达木盆地东部地区不整合类型与控油特征、不整合结构与油气运聚特征以及不整合运聚油气的成藏模式.柴达木盆地东部地区经历了多次构造运动的改造,形成了多个不整合.根据不整合在油气运聚中的作用,以不整合的成因机制及地震反射特征为基础将柴达木盆地东部地区不整合划分为褶皱、断褶、削截、超覆和平行5种类型.风化剥蚀程度的不均一性使不整合具有典型的层状结构,即不整合面之上的岩石、风化粘土层和半风化岩石.不整合纵向分层结构构成油气运移的双重通道,同时为油气聚集提供良好的储集空间和圈闭条件.不整合发育部位及剖面形态的差异,导致不同类型的不整合形成不同的油气成藏模式.     

Seasonal Characteristics of Precipitation Occurrences in the Core Area of the Subtropical High

Based on the National Centers for Envioromental Prediction（NCEP）Reanalysis 2 daily data and the Global Precipitation Climatology Project（GPCP）1 Degree Daily（1DD）precipitation data from 1997 to 2006,seasonal characteristics of precipitation occurring in the core area of the subtropical high（STH）were investigated by the frequency analysis method.The results indicate that precipitation occurs in the core area of the STH in each season,which is inconsistent with the common knowledge.In summer,there exists 40%–80%of the precipitation frequency in the STH,against less than 50%in other seasons.Generally,the seasonal mean rain rate inside the STH is about 1–2 mm day -1 in winter and less than 4 mm day -1 in summer,which contributes to about 30%–90%of the local total precipitation.In summer,such a contribution is about 50%–90%,and it is less than 40%in other seasons.Statistically,the occurrence frequency of the updraft within the core area of the STH varies from 25%to 75%in summer and less than 25%in other seasons. The results also reveal that there is about 30%of the STH frequency over the eastern China in summer, and the corresponding precipitation and updraft frequencies are 25%and 15%respectively.This is the so-called unique precipitation pattern in summer in eastern China,i.e.,precipitation is controlled by the core of the STH. Additionally,more than half of the precipitation occurring in the STH is accompanied with updraft at 500 hPa while less than half is with downdraft at 500 hPa.The former may represent deep precipitation whereas the latter may hint shallow precipitation in the core area of the STH.     

Optical properties of cirrus transition zones over China detected by CALIOP

A transition zone near cirrus lateral boundaries can be detected by CALIOP (cloud–aerosol lidar with orthogonal polarization). In the present study, for such transition zones over China, a number of optical properties, such as the backscatter coefficient and depolarization ratio, showed transitional characteristics between cirrus and clear sky. The stepped horizontal profile showed sharp changes in particle number and morphology between cirrus clouds and clear sky. The color ratio, however, was unable to show cirrus transition features because of the low signal-to-noise ratio. Typical ice particles presented a color ratio of 0.55–1.25 and a depolarization ratio of greater than 0.12, which were significantly higher than those of clear sky. Therefore, optical properties in transition took the form of stepwise horizontal profiles. The proportion of typical-featured particles also demonstrated a stepped horizontal profile similar to the optical characteristics, but the relationship between the proportion and the optical characteristics was not uniform in the cirrus clouds, transition zone, and clear sky. Therefore, the optical changes in the transition zone were caused by not only the change in particle concentration, but also the change in the particles themselves. The probability density distribution of the transition-zone widths showed a positive skewness distribution, and transition zones with widths of 3–5 km occurred most frequently. Overall, transition-zone width decreased with increasing temperature and increased with increasing vertical and horizontal wind speeds. This trend demonstrated independence with the direction of the vertical and horizontal winds. These observations implied that the transitional features were caused by material exchange, such as entrainment and turbulent transport, near the cirrus lateral boundaries, and by the phase transformation of particles, such as sublimation.     

40-30kaBP青藏高原及邻区高温大降水事件的特征、影响及原因探讨

40－30kaBP相当于末次冰期大间冰阶或海洋氧同位素MIS3晚期。青藏高原在岁差周期夏季高太阳辐射作用下,据古里雅冰芯与若干孢粉记录指示温度比现在高2－4℃,高原及邻区众多大湖的高湖面记录指示大范围降水丰沛。应用Kutzbach水能平衡方程推算了封闭湖泊流域（青海湖、扎布耶／拉果错、阿克塞钦／甜水海）年平均降水可达640mm,560mm,260mm,分别是现代降水的1．7倍,3倍,5倍。高原及邻区包括祁连山以北和云南部分区域在内的大降水对水系河流产生了重大影响。高原内部河湖串联,水系合并;如色林错、班戈错、纳木错串联为高原上最大的内陆水系;若尔盖古湖外流并入黄河水系;长江上游大水在三峡束狭形成强烈旋涡掏蚀成低于海平面的深槽,形成了深槽中、底部的砂砾沉积。这次高温大降水事件是由高太阳辐射导致的由青藏高原高温热低压加强、热带洋面增暖蒸发强烈、南半球越赤道气流增强共同作用而形成的高原特强夏季风,同时极地冰盖迫使西风带南移也可能加强了对高原尤其是西部的降水．H3事件（27kaBP)促进了高温大降水事件的结束,H4事件（35.5kaBP)则可能短期萎缩了夏季风,使高温大降水事件呈现不稳定性特点。