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   

转动物台椭圆偏光运动轨迹分析          下载免费PDF全文

张立冬 《岩石矿物学杂志》1988,7(2):175-184

本文研究了转动物台椭圆偏光的运动规律,并用公式和图解表示椭圆偏光运动轨迹,导出的椭圆偏光方程式集中反映了各公式之间的关系。为解决椭圆偏光长轴运动轨迹,推导出计算椭圆长轴(a)和视旋转角(Ar)两个新公式,使最大视旋转角所对应的物台转角的研究有新的进展。本文重点讨论不透明矿物反射光的椭圆偏光的性质,但对透明矿物透射光的椭圆偏光也有一定意义。  相似文献   

关于二轴晶矿物光性正负判别式的讨论     

黄振恒 《矿物学报》1988,(3)

作者同意刘智星的论断:旧的二轴晶矿物光性正负判别式是错误的。本文也对刘智星的推论作了更为简明直观的解释,同时提出一个新的测定二轴晶矿物光性正负的判别式:Nm-N_(45)。应用此判别式检查了近470个二轴晶矿物的光性,发现某些文献中所记载或所引用的资料(折射率或光性符号)有错。  相似文献   

A survey of numerical methods for stochastic differential equations     

P. E. Kloeden  E. Platen 《Stochastic Hydrology and Hydraulics》1989,3(3):155-178

The development of numerical methods for stochastic differential equations has intensified over the past decade. The earliest methods were usually heuristic adaptations of deterministic methods, but were found to have limited accuracy regardless of the order of the original scheme. A stochastic counterpart of the Taylor formula now provides a framework for the systematic investigation of numerical methods for stochastic differential equations. It suggests numerical schemes, which involve multiple stochastic integrals, of higher order of convergence. We shall survey the literature on these and on the earlier schemes in this paper. Our discussion will focus on diffusion processes, but we shall also indicate the extensions needed to handle processes with jump components. In particular, we shall classify the schemes according to strong or weak convergence criteria, depending on whether the approximation of the sample paths or of the probability distribution is of main interest.  相似文献   

用王水分解含金矿物的机理探讨   总被引：2，自引：0，他引：2  

王占国 《铀矿地质》1989,5(5):311-316

本文从理论上对王水分解含金矿物的机理进行了探讨。在非标准状态下,温度、压力不变,改变体系中物质的浓度、酸度条件,用能斯特公式求解体系中HNO_3和Au的电极电位值,而后用EMF(电池电动势)根据规则判断反应是否可以进行。经理论计算,结论是可行的。另外由于Au~(3 )和Cl~-大量存在时,生成稳定的[AuCl_4]~-,经过络合作用,促使了HNO_3和Au的氧化还原反应,最终使含金矿物溶解完全。作者认为王水同含金矿物反应的机理是:氧化和络合的双重作用。  相似文献   

三分量地震资料中各向异性检测     

张中杰  滕吉文  何樵登  魏计春  王爱武 《吉林大学学报(地球科学版)》1994,(1)

各向异性研究是当令地震学研究领域中重要课题之一；三分量地震资料中各向异性的检测是各向异性理论研究成果解决地球科学实际问题的重要桥梁。本文简要描述了各向异性介质中横波分裂现象，分别介绍了现有的四种主要检测技术，即偏振图法、协方差拒阵法、质，点振动分辨率法及传输矩阵法，并对这四种技术作了一定的评述。  相似文献   

由电子探针分析数据估算角闪石、黑云母中的Fe~（3＋）、Fe~（2＋）     

林文蔚  彭丽君 《吉林大学学报(地球科学版)》1994,(2)

待定矿物化学式中阳离子数法是由电子探针分析值求矿物中Ｆｅ￣（３＋）、Ｆｅ￣（２＋）的新方法。在该方法中，矿物化学式中的阴离子数是唯一已知条件，阳离子数未知，通过本文给出的一系列步骤可以得出实际阳离子数的可能估计。进而求出Ｆｅ＿２Ｏ＿２、ＦｅＯ。该法对Ｆｅ＿２Ｏ＿３、ＦｅＯ的计算结果避免了出现负值，在总体上，该方法的计算结果较其它方法更接近其化学分析值。  相似文献   

Acoustic reflection calculation using transfer matrices     

G. W. Farnell 《Geophysical Journal International》1994,118(2):358-368

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用解析有限元法嵌入地下水管理模型求最优解   总被引：1，自引：0，他引：1       下载免费PDF全文

陈雨孙 《水科学进展》1994,5(1):50-57

为了弥补当前地下水资源优化管理模型中通用的两种构模方法的缺点,即嵌入法的代数方程组过于庞大、上机困难,和响应矩阵法不保证全局最优,提出了用解析有限元法建立整体非稳定(即带有时间变量)抽水响应矩阵作为约束条件嵌入线性规划模型.这一方法由于具备了空间上表达任一节点在任一时刻的地下水运动规律的能力,克服了上述构模的两大缺点,其推广应用将有利于提高地下水资源的优化开发和管理.  相似文献   

Rangeland production: use of models incorporating aggregated knowledge and fuzzy construction     

Thomas D. A.  Ximing Sun 《Journal of Arid Environments》1995,30(4)

This work reports on a method using fuzzy membership functions to construct an aggregated interaction matrix in which the summation of variables is scaled according to the way rainfall and soil variables affect water availability to plants and hence influence rangeland productivity. Aggregation of the variables gives a comprehensive value which can be used to predict production. The model increases the predicability of production to 81% compared to models using rainfall alone and a multiplicative parametric one which give predictibilities of 61 and 76% respectively. The results showed that (1) the importance of rainfall in determining production was most important at lower rainfalls i.e. <350 mm; (2) soil texture and particularly slope were important through out the rainfall range (149–700 mm) investigated; and (3) soil depth was only important at the higher >350 mm rainfalls. The aggregated interaction matrix gives a measure of land productive capability.  相似文献