Soil moisture potential and water content in the unsaturated zone within the arid Ejina Oasis in Northwest China   总被引：2，自引：0，他引：2  

X. Zhou  L. Wan  B. Fang  W. B. Cao  S. J. Wu  F. S. Hu  W. D. Feng 《Environmental Geology》2004,46(6-7):831-839

Three soil profiles were selected in the Ejina Oasis, northwest China, to determine water content profiles and evolution of soil moisture potentials in the unsaturated zone within the arid area. The total soil moisture potentials have been monitored for about 3 months in 2001 at different depths in the soil profiles. The occurrence and movement of water in the unsaturated zone was analyzed using the zero flux plane (ZFP) method. It is shown that convergent ZFPs and divergent ZFPs may occur at depths between 0.5 and 3.0 m, and that the depth of the ZFPs was controlled by the root zone of plants growing on the land surface. Profiles of the total soil moisture potentials were observed to be coincident with those of the water contents at the three experimental sites. The total soil moisture potential showed a slight increasing trend and the ZFPs tend to vanish from summer to winter as the water extraction by roots decreased. Evapotranspiration through vegetation has an important bearing on the water content and the total potential in the unsaturated zone.  相似文献   

Estimate of Loading Rate for a TBM Machine Based on Measured Cutter Forces   总被引：1，自引：1，他引：1  

Z. X. Zhang 《Rock Mechanics and Rock Engineering》2004,37(3):239-248

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A Finite Volume Scheme for the Transport of Radionucleides in Porous Media     

E. Chénier  R. Eymard  X. Nicolas 《Computational Geosciences》2004,8(2):163-172

The COUPLEX1 Test case (Bourgeat et al., 2003) is devoted to the comparison of numerical schemes on a convection–diffusion–reaction problem. We first show that the results of the simulation can be mainly predicted by a simple analysis of the data. A finite volume scheme, with three different treatments of the convective term, is then shown to deliver accurate and stable results under a low computational cost.  相似文献   

Application of Remote Sensing in Flood Management with Special Reference to Monsoon Asia: A Review   总被引：4，自引：1，他引：4  

Sanyal  Joy  Lu  X. X. 《Natural Hazards》2004,33(2):283-301

The conventional means to record hydrological parameters of aflood often fail to record an extreme event. Remote sensingtechnology along with geographic information system (GIS)has become the key tool for flood monitoring in recent years.Development in this field has evolved from optical to radarremote sensing, which has provided all weather capabilitycompared to the optical sensors for the purpose of flood mapping.The central focus in this field revolves around delineation of floodzones and preparation of flood hazard maps for the vulnerable areas.In this exercise flood depth is considered crucial for flood hazardmapping and a digital elevation model (DEM) is considered to bethe most effective means to estimate flood depth from remotelysensed or hydrological data. In a flat terrain accuracy of floodestimation depends primarily on the resolution of the DEM. Riverflooding in the developing countries of monsoon Asia is very acutebecause of their heavy dependence on agriculture but any floodestimation or hazard mapping attempt in this region is handicappedby poor availability of high resolution DEMs. This paper presents areview of application of remote sensing and GIS in flood managementwith particular focus on the developing countries of Asia.  相似文献   

Crustal deformation and stress localization in Kanto-Tokai, central Japan revealed by GPS     

S. Zhao  X. Wu  T. Hori  Y. Kaneda  S. Takemoto 《Geophysical Journal International》2004,157(2):737-752

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Impact of inner core rotation on outer core flow: the role of outer core viscosity     

J. Y. Guo  P. M. Mathews  Z. X. Zhang  J. S. Ning 《Geophysical Journal International》2004,159(1):372-389

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Towards a long-term monitoring of Central European water mite faunas (Acari: Hydrachnidia and Halacaridae) – considerations on the background of data from 1900 to 2000     

Reinhard Gerecke  Erwin O. Lehmann 《Limnologica》2005,35(1-2):45-51

The state of knowledge of the Central European water mite fauna and the research history are briefly surveyed. Several areas for which we are provided with rich data sets are of high value for the monitoring of faunistic trends on the background of local and global environmental change. The need for a database combining historical and actual faunistic information is stressed. It should facilitate the access to all data from former times, give a survey on actual activities by regular updates, and help for a better organization of future research activities. On the base of an update of the Limnofauna Europaea (K.O. Viets 1978, Gerecke in www.watermite.org) a first attempt is made to (1) recognize changes in the Central European fauna during the past 100 years; (2) emphasize species which may be endangered or have disappeared during the past 100 years. At the present state of knowledge, the degree of threat to water mite species in this area is best calculated from their preference for particular habitat types which are rare and in danger to disappear in cultivated landscapes. Our knowledge concerning neozoic water mites in the study area is discussed.  相似文献   

Modelling of multiple events using empirical Green''s functions: method, application to swarm earthquakes and implications for their rupture propagation     

Tomá&#; Fischer 《Geophysical Journal International》2005,163(3):991-1005

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Climatic response of thick leaf spruce (Picea crassifolia) tree-ring width at different elevations over Qilian Mountains, northwestern China   总被引：3，自引：0，他引：3  

X. Gou  F. Chen  M. Yang  J. Li  J. Peng  L. Jin 《Journal of Arid Environments》2005,61(4):513-524

Tree-ring cores of thick leaf spruce (Picea crassifolia) taken from four sites at different elevations, in the middle of the Qilian Mountains, in the arid and semi-arid region of northwestern China, were used to develop four tree-ring width chronologies using standard dendrochronological methods. Results indicate that with increasing altitude the chronologies’ year-to-year variations decreased. Hence, the sensitivity of the tree-ring chronologies to climate decreases with altitude. Further analysis showed that the significant limiting factor on tree growth is spring precipitation. Measurements of stomata density and leaf dry weight suggest the species’ ecological adaptation strategy changes with elevation. At high elevation the metabolic rate of thick leaf spruce decreases, thus showing the effect of the climate.  相似文献   

Dynamic characteristics analysis of shallow landslides in response to rainfall event using GIS     

H. X. Lan  C. F. Lee  C. H. Zhou  C. D. Martin 《Environmental Geology》2005,47(2):254-267

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