Impact of Flood Disasters on Taiwan in the Last Quarter Century

The increasing natural disasters, especially floods during the last quarter century, are raising the economic losses in Taiwan. The most severe hazard in Taiwan is flooding induced by typhoons and storms in summer and autumn. By comparing the rivers around the world, the ones in Taiwan have the steepest slopes, the largest discharge per unit drainage area, and the shortest time of concentrations. Rapid urbanization without proper land uses managements usually worsen the flood problems. Consequently, flood hazards mitigation has become the most essential task for Taiwan to deal with. Although the government keeps improving flood defense structures, the flood damage grows continuously. In this article, possible flood mitigation strategies are identified for coping with complex environmental and social decisions with flood risk involved.     

卫星遥感监测ET方法及其在水管理方面的应用

概述了利用遥感技术监测流域蒸发(ET)用于流域水管理的研究,利用卫星遥感监测ET比传统地面监测ET方法具有更高的经济合理性和实用性;通过遥感监测的ET,不仅可以对农业用水效率、灌溉系统性能作出更符合实际的评价,还可服务于流域水资源管理和区域水资源利用规划。随着信息技术的快速发展,卫星遥感监测ET的方法在水管理方面的应用前景广阔,我国应加强对该技术的研究和应用。     

非均匀陆面条件下区域蒸散量计算的遥感模型

非均匀陆面条件下的区域蒸散计算是一个复杂的问题。文中首先在利用遥感资料求取地表特征参数 (如植被覆盖度、地表反照率等 )的基础上 ,建立了裸露地表条件下的裸土蒸发和全植被覆盖条件下植被蒸腾计算模型 ,然后结合植被覆盖度 (植被的垂直投影面积与单位面积之比 )给出非均匀陆面条件下的区域蒸散计算方法。实测资料验算表明该模型具有较高的计算精度。文章最后利用该模型对中国北方地区的蒸散量进行了计算 ,并对该研究区蒸散的特点进行了分析     

施放氢气球时存在的安全隐患及防范措施

针对采用球服务中的安全隐患，提出有效的防范措施，对开展此项工作的同志有很好的借鉴意义。     

吐哈盆地侏罗纪煤中主要组分结构特征与生烃性分析

在高纯度煤岩显微组分分离富集的基础上,应用透射式显微傅里叶红外光谱技术 (Micro FTIR),对吐哈盆地侏罗纪煤中的主要组分-镜质体、丝质体、角质体、藻类体的结构组成进行了测定。结果表明 :藻类体主要由长链脂族结构组成,芳香结构含量相对较少;角质体和基质镜质体中含有较丰富的芳香结构以及长链脂族结构;而丝质体则主要由芳香结构组成,脂族结构含量很少。显微组分的这种结构特征决定了藻类体具有很高的生烃潜力、角质体和镜质体的生烃潜力中等、而丝质体的生烃潜力则很低。对于吐哈盆地煤成油来说,由于藻类体主要由长链脂族结构组成,并且生烃潜力也高,因此其具有高的液态烃产率、丝质体的产油率最小、角质体和镜质体的液态烃产率中等。由于镜质体是本区煤中含量最高的组分。因此,对于吐哈盆地所形成的具有工业规模的油田来说,镜质体应该是主要的贡献组分之一。但对于富含藻类体的厚层状烛藻煤,由于它类型好,品质高、生烃潜力大、以中长链脂族结构为主,是煤成油最理想的源岩。     

Implications of the relationship between catchment vegetation type and the variability of annual runoff

The impact of changing catchment vegetation type on mean annual runoff has been known for some time, however, the impact on the variability of annual runoff has been established only recently. Differences in annual actual evapotranspiration between vegetation types and the potential effect of changing vegetation type on mean annual runoff and the variability of annual runoff are briefly reviewed. The magnitude of any change in the variability of annual runoff owing to a change in catchment vegetation type is related to the pre‐ and post‐change vegetation types and the seasonality of precipitation, assuming that the variability of annual precipitation remains constant throughout. Significant implications of the relationship between vegetation type and the variability of annual runoff are presented and discussed for water resource management, stream ecology and fluvial geomorphology. Copyright © 2002 John Wiley & Sons, Ltd.     

Division of Gas Accumulation System and Laws Controlling Distribution of Natural Gas in Typical Petroliferous Basins of China

Considering the existing problems of the petroleum system, this paper brings forward the concept of natural gas accumulation system and presents the dividing principles. Then detailed statistics on the accumulation factors of the 32 typical natural gas accumulation systems in China and studies on the laws controlling distribution of gas are collected. The research shows that the petroleum accumulation system is the basic unit controlling petroleum generation, migration and accumulation. Generating intensity, generating amount, accumulating efficiency and migration distance plays an important role in the distribution of natural gas. Through analysis on results of resources evaluation, discovered reserves and residual reserves, potential areas in middle-scaled petroliferous basins in China are forecasted in this paper. Ordos, Sichuan, Tarim and Qaidam basins are found out to be the main basins developing and enriching gas accumulation systems.     

Evapotranspiration from citrus trees growing in sandy soilunder drip irrigation with saline water

An experiment on evapotranspiration from citrus trees under irrigation with saline waterwas carried out for 4 months. Two lysimeters planted with a citrus tree in the green house wereused. One lysimeter was irrigated with saline water (NaCl and CaCl2 of 2000 mg/L equivalence,EC = 3.8 dS/m, SAR = 5.9) and the other was irrigated with freshwater using drip irrigation. Theapplied irrigation water was 1.2 times that of the evapotranspiration on the previous day.Evapotranspiration was calculated as the change in lysimeter weight recorded every 30 minutes.The lysimeters were filled with soil with 95.8% sand. The results of the experiment were as follows.(i) The evapotranspiration from citrus tree was reduced after irrigation with saline water. Theevapotranspiration returns to normal after leaching. However it takes months to exhaust the saltfrom the tree. ( ii ) To estimate the impact of irrigation with saline water on the evapotranspirationfrom citrus trees, the reduction coefficient due to salt stress (Ks) was used in this experiment.Evapotranspiration under irrigation with saline water (ETs) can be calculated from evapotranspira-tion under irrigation with freshwater (ET) by the equation ETs = Ks× ET. Ks can be expressed as afunction of ECsw. (iii) The critical soil-water electrical conductivity (ECsw) is 9.5 dS/m, beyondwhich adverse effects on evapotranspiration begin to appear. If ECsw can be controlled at below9.5 dS/m, saline water can be safely used for irrigation.     

Solar–terrestrial effects possibly stronger in biblical times

Paleomagnetic studies have shown that, moving backwards in time, the geomagnetic dipole moment increased to a peak nearly 50% greater than at present ca. 2500 years ago. Attempts to model how changes in dipole moment affect solar–terrestrial relations have hitherto invoked a scaling relation for the size of the magnetosphere based on finding where the magnetic pressure of the dipole field balances the ram pressure of the solar wind. This approach predicts that, following a solar storm, the strength of the terrestrial response represented by the electrical potential across the auroral zones in the ionosphere should vary as the 1/3 power of dipole moment. Such a weak dependence suggests that a 50% increase in dipole moment would minimally effect (14%) terrestrial manifestations of solar storms. Recent work, however, based on a feedback mechanism involving electrical currents coupling the magnetosphere and ionosphere has identified a stronger 4/3, power scaling relation applicable to storm conditions. Here we use a global MHD simulation to calculate for a 50% increased dipole moment the correspondingly increased auroral-zone potential and its extension to low latitudes.     

固体介质中弹性波传播机制的细胞自动机有限深势阱模型

分析了采用细胞自动机研究波动问题的建模方法，针对一维、均匀、各向同性固体介质中弹性纵波的微观机制，借用一经典弹簧振子模型、细胞自动机格子气模型，以及量子力学中的无限深势阱模型，建立了一个细胞自动机有限深势阱模型，从量子力学角度出发，基于介观物理和纳米概念，以微观精子的德布罗意假设为基础，利用薛定谔方程，讨论了该模型中粒子（分子组）的振动速度与粒子物质波波速之间的联系，给出了模型中的波动方程，得出ζ＝Vp（ζ为粒子振动速度，Vp为物质波纵波波速）。同时还讨论了模型中粒子的大小和能量传递问题，引入引力场，得出了能量及引力势的量子化条件，另外，对声波速度、格子气粒子振动速度和本文模型中分子组振动速度进行了比较；还对本文模型中的粒子能量分布作了分析。