Effect of connecting rain barrels on the storage size reduction

In this article, the possibility of sharing rain barrels and the potential benefit of reducing storage size through physical and non‐physical connections of rain barrels in a community are investigated. Using the concepts of homogeneous/heterogeneous users in rainwater harvesting systems (RWHS), two simple cases of a community composed of four prospective users are examined. The first is performed with the users who have the same mean and variance in water demands (homogeneous users), and the second is with the users with different means and variances (heterogeneous users). To take account for the rainfall characteristics in different places, historical records from six cities in the USA are used for storage–reliability–yield analysis. The result indicates that required total storage can be reduced by connecting multiple rain barrels. In addition, a significant difference is found between homogeneous and heterogeneous user groups. Homogeneous users do not achieve a substantial benefit from connecting their rain barrels; these users may even be disadvantaged by sharing. In contrast, heterogeneous users receive benefit by reducing the total required storage. Most benefit is expected between users with maximum difference in mean water demands. The reduction in storage size was as considerable as 37% in this study. The quantity of storage reduction depends on locations and target reliabilities. Knowledge of the benefits and limitations of rain barrel connections can improve RWHS performance through ability to customize a network plan for individual users. Copyright © 2011 John Wiley & Sons, Ltd.     

Direct observation of complex Tóthian groundwater flow systems in the laboratory

Based on the theory of gravity‐driven groundwater flow systems, we have developed a complex Flow System Sand‐Box Model (FSM). It enables the visual observations of the development and characteristics and temporal evolution of complex Tóthian flow systems in the laboratory. The configuration of the regional, intermediate and local flow systems can be controlled and observed; hydraulic head, flow direction and travel time can be measured; and the scale and shape of the sub‐flow systems as well as the path lines and flow lines can be observed directly. The experiments demonstrate the Tóthian flow systems in a small basin with multiple sources and sinks. Greater local topographic (water table) undulation will lead to larger local flow systems. Greater regional and less local topographic undulation will enhance the development of intermediate and regional flow systems. In homogeneous media, increasing fluid‐potential differences between source and sink increase the spatial scale of the generated flow systems. The FSM is a useful teaching aid and experimental device to study and develop an intuitive insight into gravity‐driven groundwater flow systems. It helps to visualize and understand the hydraulic properties and controlling factors of Tóthian flow systems and may be used to study problems related to the chemical and temperature characteristics of the flow systems as well. Copyright © 2010 John Wiley & Sons, Ltd.     

Reply: Bulk sampling of coarse clastic sediments for particle-size analysis

The work of Gale and Hoare (1992) provides a guide to the minimum mass of bulk sample required to obtain a reproducible measure of the complete particle-size distribution of coarse clastic sediments such as till, fluvial gravel and beach gravel. Dunkerley (1994) makes a number of criticisms and misrepresentations of this procedure. These are systematically refuted and corrected here, and further data obtained from till and beach gravel are provided to support the criterion adopted by Gale and Hoare (1992) for sample reliability. The procedure of Gale and Hoare (1992) is confirmed as a practical guide to the mass of bulk sample required to obtain a reliable measure of the particle-size distribution of coarse clastic sediment.     

北上热带气旋发展与不发展的对比分析

重点分析了一个北上热带气旋（８５０９号台风）变性发展过程中扰动能和扰动有效有效位能的收支平衡关系及其与中纬地区高空环境场、Ｑ矢量散度、旋度特征和锋生锋消现象的联系，并和与此台风前期路径及强度相似、但进入西风带后很快消失了的８４０６号台风的诊断结是要 进行了对比。结果表明：有利的大尺度环境是台风变性发展的主要因子和先决条件，斜压过程是否能有效和大量地制造扰动动能以抵消台风北上过程中的能量耗散是其能否     

关于地震预报决策程序问题的讨论

地震预报决策是大家所关心的问题。地震预报决策正确与否,关系到能否达到减灾目的。科学的地震预报决策程序是实现正确的地震预报决策的保证。本文就地震预报决策中有关决策目标的确定,地震预测,震害预测,地震对策,预报决策备择方案的制定及评估,决策方案的选择及实施等问题进行了讨论。     

甘肃及其邻域地壳中间界面的某些性质

本文根据地壳中间界面上反射波的运动学和动力学参数，探测了地壳中间界面的埋深、复盖介质中波的传播速度、温度、压力、反射性、透过性、弹性等性质。     

东海陆架盆地岩石密度与磁性

本文在东海陆架盆地２０口钻井１６０块岩心标本物测定和１７口钻井密度测井的基础上，通过整理、分析、统计，给出了东海陆架盆地的岩石密度和磁性特征。     

Physical,radiative, and dynamical processes within a nighttime marine stratus cloud

Observations taken by aircraft and conventional platforms are used to investigate dynamical, physical, and radiative processes within a marine stratus cloud during the Canadian Atlantic Storms Program (CASP) II field project which took place over the east coast of Canada. Stratus which formed over the ocean on February 6, 1992 during the nighttime, is studied to analyze cloud top and base processes. The cloud was supercooled during the study period. Fluctuations and fluxes are calculated along constant flight altitude legs approximately 100 km long in space. The scales of structures larger than 5 km are removed from the analysis using a running average technique. Droplet spectra obtained by a forward scattering spectrometer probe (FSSP) were used in a 1-D radiative transfer model to calculate infrared (IR) fluxes and radiative heating rates. A heat conservation equation was used to estimate vertical air velocity (w _a ) within the cloud. The results showed that, because of a warmer ocean surface, significant moisture and heat were transferred from the ocean surface to the boundary layer. The cloud base was at about 400 m height and the top was at about 1.4 km.w _a at the cloud base was estimated about 5 cm s^–1. Strong IR cooling rate at the cloud top was calculated to be 75°C day^–1 for a 100 m thick layer. Negative skewness inw _a , suggesting narrow downdrafts, was likely due to radiative cooling at the cloud top. The entrainment velocity was found to be about 1.5 cm s^–1 at cloud top. Mean moisture and heat fluxes within the cloud were estimated to be comparable to those from the ocean surface. Vertical air velocity at the cloud top due to radiative cooling was found to be about –40 cm s^–1.     

暴雨类冷涡与非暴雨类冷涡的合成对比分析

选择了８例典型的东北冷涡暴雨过程和８例典型的东北冷涡弱降水过程进行了合成对比分析，发现暴雨类冷涡其暴雨主要出现在冷涡的发展阶段，而非暴雨类冷涡的降水主要发生在冷涡的成熟阶段；暴雨类冷涡与其南侧的副热带低值系统联系密切，非暴雨类冷涡的这一特点不甚明显；暴雨类冷涡的两个降水中心分别出现在系统东侧偏南和南侧偏东一些的地，距系统中心大约３００－４００ｋｍ和７００－８００ｋｍ，这些区域处于低层辐合、高层辐菜