Characteristics of canopy interception loss in Moso bamboo forests of Japan     

Yoshinori Shinohara  Kohei Kuramoto  Kyoichi Otsuki 《水文研究》2013,27(14):2041-2047

In recent years, Moso bamboo (Phyllostachys pubescens) forests have rapidly expanded in Japan by replacing surrounding coniferous and/or broadleaved forests. To evaluate the change in water yield from forested areas because of this replacement, it is necessary to examine evapotranspiration for Moso bamboo forests. However, canopy interception loss, one of the major components of evapotranspiration in forested areas, has been observed in only two Moso bamboo forests in Japan with relatively high stem density (~7000 stems/ha). There are, in fact, many Moso bamboo forests with much lower stem density. Thus, we made precipitation (Pr), throughfall (Tf) and stemflow (Sf) observations for 1 year in a Moso bamboo forest with stem density of 3611 stems/ha and quantified canopy interception loss (Ic). Pr and Ic for the experimental period were 1636 and 166 mm, respectively, and Ic/Pr was 10%. The value was approximately the same as values for the other two Moso bamboo forests and lower than values for coniferous and broadleaved forests. On the other hand, Tf/Pr and Sf/Pr for our forest (86% and 4%, respectively) were approximately 10% of Pr larger and smaller than values for the other two Moso bamboo forests. These results suggest that the difference in stem density greatly affects precipitation partitioning (i.e. Tf/Pr and Sf/Pr) but does not greatly change Ic/Pr. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Energy balance and evaporation loss of an agricultural reservoir in a semi‐arid climate (south‐eastern Spain)     

B. Gallego‐Elvira  A. Baille  B. Martín‐Górriz  V. Martínez‐Álvarez 《水文研究》2010,24(6):758-766

A typical agricultural water reservoir (AWR) of 2400 m² area and 5 m depth, located in a semi‐arid area (southern Spain), was surveyed on a daily basis for 1 year. The annual evaporation flux was 102·7 W m^?2, equivalent to an evaporated water depth of 1310 mm year^?1. The heat storage rate G exhibited a clear annual cycle with a peak gain in April (G ～ 45 W m^?2) and a peak loss in November (G ～ 40 W m^?2), leading to a marked annual hysteretic trend when evaporation (λE) was related to net radiation (R_n). λE was strongly correlated with the available energy A, representing 91% of the annual AWR energy loss. The sensible heat flux H accounted for the remaining 9%, leading to an annual Bowen ratio in the order of 0·10. The equilibrium and advective evaporation terms of the Penman formula represented 76 and 24%, respectively, of the total evaporation, corresponding to a annual value of the Priestley–Taylor (P–T) coefficient (α) of 1·32. The P–T coefficient presented a clear seasonal pattern, with a minimum of 1·23 (July) and a maximum of 1·65 (December), indicating that, during periods of limited available energy, AWR evaporation increased above the potential evaporation as a result of the advection process. Overall, the results stressed that accurate prediction of monthly evaporation by means of the P–T formula requires accounting for both the annual cycle of storage and the advective component. Some alternative approaches to estimating R_n, G and α are proposed and discussed. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

均匀离散分布的平面应变过程和Fry法应变测量     

杨新岳 《大地构造与成矿学》1993,17(1):82-92

本文运用 Apple Macitonsh 计算机对无应变的均匀离散点分布进行系列平面应变模拟,应变叠加模式分别采用具普遍意义的成岩压实+顺层缩短(LPS)+压溶作用和成岩压实+简单剪切+压溶作用。对各应变阶段的变形点分布进行相应的 Fry 法应变测量,并配合低变形砂岩样品的 Fry 法应变分析实例.证实 Fry 法应变测量方法为一非常有用的应变测量方法,其结果不仅能较好地揭示全岩总应变特征,而且能揭示出许多应变叠加的信息,Fry 法揭示的全岩有限应变椭球主面的方位也较为真实可靠。而 Fry 法运用于应变分布不均匀的劈理化岩石中时,能揭示不同变形域的应变特征,从而达到应变分解的目的。  相似文献   

钨、锡流-熔分配实验结果及其矿床成因意义   总被引：4，自引：1，他引：4  

陈子龙  彭省临 《地质论评》1994,40(3):274-282

本文用实验确定了钨、锡在成分不同的花岗质熔体相与共存水热流体相的流-熔分配系数(D_(Me)~(V/L))及其与介质溶液(NaF,KF,HF,NaCl等水溶液)摩尔浓度间的函数关系。实验结果表明,钨、锡的分配行为明显不同。在相同条件下,随体系的不同,D_W~(V/L)比D_(Sn)~(V/L)大几倍至二十倍。钠和钾对钨、锡的流-熔分配行为的影响基本相同,而氟和氯对钨、锡的分配行为的影响相差甚远,花岗质熔体的主成分对D_W~(V/L)和D_(Sn)~(V/L)有复杂的影响。利用这些结果探讨与花岗岩有关的钨、锡矿床的成矿机理,得出了一些与前人不同的新认识。  相似文献   

Suspended particulate grain size dynamics and their implications for trace metal sorption in the Don River     

Lesley A. Warren  Ann P. Zimmermann 《Aquatic Sciences - Research Across Boundaries》1994,56(4):348-362

We examined particle size distributions of suspended particulate matter (SPM); physical and environmental influences on the observed distributions; and relationships between particle size and geochemical partitioning of metals, over the fall and winter period in a small urban river (Don River, Toronto, Ontario, Canada). For this dataset, the majority of particles (80%) in suspension were less than 10 µm in size. In addition, while total SPM concentrations showed a positive trend with increasing discharge (Q); the proportions of particles found within given size classes were independent of both SPM concentration and Q. Temperature was the only measured environmental variable related to the particle concentrations within size classes. As water temperature increased, the concentration of particles in the smallest size class (1–4 µm) decreased, while the concentration of silt and/or algae sized particles (10–50 µm) increased. Increasing water temperatures may promote bacterial attachment to particles and their subsequent flocculation into larger sized particles. Decreasing concentrations of leachable (most labile) Cd, Zn and Mn were associated with increasing concentrations of the largest particles (70–150 µm) in suspension. In contrast, higher reducible (oxides) associated concentrations of Cd, Zn and Mn occurred with increasing concentrations of smaller particles (1–10 µm) in suspension. Both of these trends are speculated to reflect the importance of particle surface area for metal sorption reactions.  相似文献   

A continuous kinematic model of plate-tectonic motions     

David Bercovici  Pål Wessel 《Geophysical Journal International》1994,119(2):595-610

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地震过程中形变能的演化特征     

张永志 《地震研究》1994,17(2):171-176

本文利用非线性理论分析了震前形变能随时间的演化关系，导出了应力与应变的本构关系为非线性时的突变演化模型。最后利用青海门源６．４级地震前后的跨断层形变资料，计算了非线性形变的演化过程。取得如下认识：１．震前形变能的演化过程是不稳定过程；２．形变能的突变发生在非平衡区；３．门源地震前后的跨断层地形变资料的计算结果与理论分析基本一致。  相似文献   

桂北一洞锡矿床稀土元素地球化学研究     

张杰  税哲夫 《地质与勘探》1995,31(2):23-29

通过对矿床中各类型矿石中的锡石、与成矿有关的岩体及围岩稀土元素地球化学分析，探讨了各成矿阶段锡石中稀土元素的组成模式、总量和特征值的变化规律及原因，成矿物质及稀土元素具多来源性，岩浆岩及围岩中稀土酚模显示其具有同成因特征。  相似文献   

新疆钻孔应变异常特征及其与地震三要素关系研究     

蒋靖祥  许风柱  闫均科 《内陆地震》1995,(2)

将新疆高精度钻孔应变仪１０年来观测到的应变异常划分为趋势异常、短期异常、临震异常三类，并对这三种异常的特征进行了分析总结．认为，地震三要素与应变异常参量关系密切，震级与异常量级、震中距有着确定性关系。  相似文献   

粘滑失稳及其物理场时空分布的实验研究   总被引：6，自引：3，他引：6  

邓志辉  马胜利 《地震地质》1995,17(4):305-310

摩擦滑动的物理场实验研究表明：（１）能量空间分布的差异是失稳的重要条件，单发型大事件常发生于高能量向低能量的突变带或高能量背景区内的相对低能量区；（２）单发型大事件的孕育过程常常经历若干个能量输入输出循环，产生多个前兆阶段，并在失稳前源区常有一个弱化过程。小震或群发型事件失稳前常常只有一个能量积累与强化的过程，失稳前兆阶段性反映较差；（３）粘滑失稳时断层的位错与声发射的大小未见明显关系  相似文献