A MESO-β SCALE SIMULATION OF THE EFFECTS OF BOREAL FOREST ECOSYSTEM ON THE LOWER ATMOSPHERE

Based on the Intensive Field Campaign(IFC-1)data of Boreal Ecosystem-Atmosphere Study(BOREAS).a three-dimensional meso-β scale model is used to simulate the effect of boreal forests onthe lower atmosphere.A fine horizontal resolution of 2 km×2 km is used in order to distinguish thevegetative heterogeneity in the boreal region.A total of 20×25 grid points cover the entire sub-modeling area in BOREAS' South Study Area(SSA).The ecosystem types and their coverage ineach grid square are extracted from the North American Land Cover Characteristics Data Base(NALCCD)generated by the U.S.Geographical Survey(USGS)and the University of Nebraska-Lincoln(UNL).The topography of the study area is taken from the Digital Elevation Map(DEM)of USGS.The model outputs include the components of the energy balance budget within the canopyand at the ground.the turbulence parameters in the atmospheric boundary layer and the wind.temperature and humidity profiles extending up to a height of 1500 m.In addition to the fine timeand spatial step,the unique feature of the present model is the incorporation of both dynamic andbiological effects of the Boreal forest into the model parameterization scheme.The model resultscompare favorably with BOREAS' IFC-1 data in 1994 when the forest was in the luxuriant growingperiod.     

流褶层及韧变带研究

流褶层与韧变带是地壳拉伸变形，顺层固态流变作用下的产物。流褶层是以原始层理为变形面或再经递进变形的褶皱变形岩层或岩石共生组合层位。韧变带具明显的层控性，受岩石成分和应变程度控制，不同环境和不同成分岩石的韧变带具有相异的组合型式和变形机制，井具有一定的递变规律。流褶层和韧变带可分属不同层位，但流褶层可实现向韧变带的转化。     

Low-cost volcano surveillance from space: case studies from Etna, Krafla, Cerro Negro, Fogo, Lascar and Erebus

 Satellite data offer a means of supplementing ground-based monitoring during volcanic eruptions, especially at times or locations where ground-based monitoring is difficult. Being directly and freely available several times a day, data from the advanced very high resolution radiometer (AVHRR) offers great potential for near real-time monitoring of all volcanoes across large (3000×3000 km) areas. Herein we describe techniques to detect and locate activity; estimate lava area, thermal flux, effusion rates and cumulative volume; and distinguish types of activity. Application is demonstrated using data for active lavas at Krafla, Etna, Fogo, Cerro Negro and Erebus; a pyroclastic flow at Lascar; and open vent systems at Etna and Stromboli. Automated near real-time analysis of AVHRR data could be achieved at existing, or cheap to install, receiving stations, offering a supplement to conventional monitoring methods. Received: 21 January 1997 / Accepted: 3 April 1997     

A transdisciplinary analysis of water problems in the mountainous karst areas of Morocco

Water management and engineering in the karstic High Atlas of Morocco are difficult tasks under the prevailing geological, hydrogeological, geomorphological, vegetational and climatic conditions. It is important to be able to understand and predict the characteristics and availability of water for future water planning in the region under changing climatic and agricultural conditions. An interdisciplinary analysis of problems and adequate hydrological modelling tools developed by geologists, hydrologists and biologists are necessary. The karst areas of the High Atlas Mountains are characterised by impermeable triassic basalt underlying substantial subsurface reservoirs with high potential discharge rates. The karst groundwater aquifers are extensive but largely unknown in dimension, probably with a hierarchical network of groundwater flow paths. It is estimated that approximately 70% of the surface water is directly lost to groundwater. Steep landslide- and debris flow prone slopes exist next to coarse-grained, highly porous river beds. Infrequent, high intensity rainfall or snowmelt causes a particularly high flood risk to these karst areas. In addition, agriculture and land use changes have degraded the karst areas. The most important driving forces for degradation include permanent overgrazing even during droughts and the use of firewood by a continually growing population. Large scale degradation of vegetation has occurred in the oro-mediterranean (mountainous Mediterranean) zone, between 2600 and 3400 m which coincides with the most important zone for karstic groundwater creation. The combination of high amounts of groundwater flow and rapid surface flow due to sparse vegetation has increased the problems of flood flow.     

过渡季节(6—7月)澳大利亚冷高压对赤道辐合带形成的影响

应用车贝雪夫多项式分析过渡季节(6—7月)澳大利亚冷高压与赤道辐合带的关系,得出了对赤道辐合带北移的主要形势以及过程演变特征,最后用合成方法得到它的演变概念模式,为赤道辐合带的北移影响西太平洋及南海地区提供了中期预报的依据。     

南海沉积岩芯的地球化学研究

本文对南海中部陆坡区和海盆区的5个岩芯中的 Si,Al,Fe,Mn,Ca,Mg 和 CaCO_3成分做了分析,并对其分布特征与有关影响因素进行了讨论。受沉积区环境差异的影响,元素的分布具有区域性特征;受海区特定地理位置的影响,元素的分布呈现出过渡性特征(浅海到大洋的过渡);受沉积过程中环境变化的影响,元素的分布展示了周期性变化或旋回性。根据岩芯中元素的分布特征,并参考有关古地磁,氧碳同位素和钙质超微化石的测试分析结果,将本区岩芯划分为14层地球化学层,并将本区划分为两个沉积地球化学区,揭示了早更新世以来本区沉积环境的变化和存在的两种沉积模式。     

Sugar and Lipid Components in Sea Foam near Kelp Beds

Abstract. A component analysis of the sugar and lipid fraction in foam layers around kelp beds on the South African west coast showed the following trends: In the residue of foam drainage of both 12 h and 120 h old foam the sugar fraction is represented by mannose (33–41 %), galactose (4–30%), fucose (3–29%) and glucose (19–26%). With the exception of fucose, the same components could be found in foam filtration. In the lipid fraction the main fatty acids are palmitic (23.3–27.3%), oleic (14.0–5.5%) and timnodonic acid (11.2–9.1%). Selacholeinic acid was only found in 12 h old foam while lignoceric acid could not be located in foam filtration. Against expectation mannitol was not identified in quantifiable amounts in foam samples although it is the dominant component of kelp mucilage, whose presence is of major importance for foam formation. Hypotheses explaining the lack of mannitol are forwarded. Component sugar and lipid content for 11 of foam was calculated and estimation of sugar and lipid content in an average foam patch (volume of 30001) is given. The importance of foam formation as a mechanism for binding and transfer of energy in the marine environment is emphasized.     

海带几个不同种的雌性克隆对高温的适应力

每几个不同种的雌性克隆对高温(22℃、24℃、26℃)的适应力有所差异。大西洋沿岸的Laminariahyperhoren和L.sacchrina雌性克隆较太平洋沿岸的L.japonica、L.angustata和L.ochotensis雌性克隆明显地不耐高温,遗传性的不同是造成这种差异的主要原因。这种遗传性差异是海带长期自然选择的结果。同一物种L.japonica和L.japonicaCⅡ两种雌性克隆在24℃条件下,在第24天其死亡率分别是40.2％和25.2％,X~2=12.25,P<0.001,差异是高度显著的,说明这种不同是遗传性不同所致,而且属于物种内部的差异。     

Study on the characteristics of the marine boundary layer in the Equatorial Pacific

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Estimating hydraulic conductivity using grain-size analyses, aquifer tests, and numerical modeling in a riverside alluvial system in South Korea

Hydraulic conductivity (K) for an alluvial system in a riverbank filtration area in Changwon City, South Korea, has been studied using grain-size distribution, pumping and slug tests, and numerical modeling. The alluvial system is composed of layers: upper fine sand, medium sand, lower fine sand, and a highly conductive sand/gravel layer at the base. The geometric mean of K for the sand/gravel layer (9.89?×?10^?4 m s^?1), as determined by grain-size analyses, was 3.33 times greater than the geometric mean obtained from pumping tests (2.97?×?10^?4 m s^?1). The geometric mean of K estimates obtained from slug tests (3.08?×?10^?6 m s^?1) was one to two orders of magnitude lower than that from pumping tests and grain-size analyses. K estimates derived from a numerical model were compared to those derived from the grain-size methods, slug tests and pumping tests in order to determine the degree of deviation from the numerical model. It is considered that the K estimates determined by the slug tests resemble the uppermost part of the alluvial deposit, whereas the K estimates obtained by grain-size analyses and pumping tests are similar to those from the numerical model for the sand/gravel layer of the riverside alluvial system.