Evapotranspiration management based on the application of SWAT for balancing water consumption: A case study in Guantao,China

Rapid social and economic development results in increased demand for water resources. This can lead to the unsustainable development and exploitation of water resources which in turn causes significant environmental problems. Conventional water resource management approaches, such as supply and demand management strategies, frequently fail to restore regional water balance. This paper introduces the concept of water consumption balance, the balance between actual evapotranspiration (ET) and target ET, and establishes a framework to realize regional water balance. The framework consists of three stages: (1) determination of target ET and actual ET; (2) quantification of the water-saving requirements for the region; and (3) reduction of actual ET by implementing various water saving management strategies. Using this framework, a case study was conducted for Guantao County, China. The SWAT model was utilized to aid in the selection of the best water saving management strategy by comparing the ET of different irrigation methods and crop pattern adjustments. Simulation results revealed that determination of SWAT model parameters using remote sensing ET is feasible and that the model is a valuable tool for ET management. Irrigation was found to have a greater influence on the ET of winter wheat as compared to that of maize, indicating that reduction in winter wheat cultivation is the most effective way to reduce regional ET. However, the effect of water-saving irrigation methods on the reduction of ET was not obvious. This indicates that it would be difficult to achieve regional ET reduction using water-saving irrigation methods only. Furthermore, selecting the best water saving management strategy by relying solely on the amount of reduced ET was insufficient, because it ignored the impact of water conservation measures on the livelihood of the agricultural community. Incorporating these considerations with our findings, we recommend changing the current irrigation method to sprinkler irrigation and replacing 20% of the winter wheat-maize cultivated area with cotton, as the best strategy to achieve water balance in the study area.     

广东新丰江水库XFJ-1孔DDTs和HCHs的沉积记录

以~(210)Pb对广东新丰江水库XFJ-1孔进行了定年,以GC-ECD测定新丰江水库沉积钻孔中DDTs和HCHs的含量,通过对比其剖面变化特征与该类农药在我国的生产、使用历史,探讨了水库中DDT、HCH的历史输入途径.过去30年来,XFJ-1孔平均沉积速率为1.42cm/a,沉积物中HCHs和DDTs的含量分别为1.26-3.90ng/g和1.00-3.96ng/g.DDTs、HCHs含量从20世纪80年代初逐渐下降,总体上与我国1983年开始禁止DDT、HCH的大规模生产和使用这一历史事件相符.DDTs、HCHs及其化合物比值的剖面变化特征均表明:流域内后期土壤侵蚀、搬运的再循环污染物质(即二次污染源)对水库DDT和HCH的贡献不明显;相反,农药历史使用(即一次污染源)是其主要来源,大气沉降是其主要输入途径.此外,γ-HCH、o,p′-DDT和p,p′-DDT含量的垂直变化表明,大规模禁用以后这些化合物仍有少量新的输入,需引起重视.     

南岭山地湖泊多环芳烃的大气沉降历史记录

高大山脉对大气环流具有阻挡或屏障作用.通过分析测定南岭山地湖泊沉积物中多环芳烃(PAHs)的垂直分布,结合210Pb定年,探讨了大气PAHs污染在南岭山地的沉积历史.结果显示,沉积物中的PAHs主要以低环数化合物为主,其中尤以菲的含量为最高.在剖面深度0～28 cm范围内,总多环芳烃的含量范围为86～778 ng/g.自1970年开始,PAHs含量持续增加,其中20世纪80、90年代中后期PAHs含量略有降低;在2000年后,沉积柱中的PAHs含量呈急剧增加之势态.多环芳烃在大气迁移过程中发生了组成分异,沉积物中相对富集轻组分(低环数)PAHs,与颗粒物结合的大气干湿沉降是PAHs向偏远山地积的主要途径.     

Seasonal variability of eddy characteristics and energetics in the Kuroshio Extension

Ocean Dynamics - Based on the eddy-resolving Four-dimensional variational Ocean Re-Analysis for the Western North Pacific over 30 years (FORA-WNP30) product, this study investigates the...     

气象灾害应急管理能力评价

建立气象灾害应急能力评价指标体系对增强应对气象灾害管理能力和提高灾害的应急响应能力有重要的意义。从系统理论的角度出发,基于气象灾害应急管理的特征和结构的分析,运用层次分析法原理,构建了由气象灾害预警防御能力、政府组织能力、支撑保障能力3个1级指标和15个2级指标组成的气象灾害应急管理能力的评价指标体系,可为提高气象灾害应急管理能力和防灾减灾提供科学依据。     

Dynamic Analysis of a Single-Column Platform (II)

This paper describes the study of a single-column structure used as well-head platform. In order to check the reliability of computation theory and programme, model tests have been carried out. The paper introduces the conclusion of tests and the dynamic properties of single-column platform are obtained.     

我国干热岩资源分布及勘探:进展与启示

干热岩是地热资源的重要赋存形式之一,是未来地热开发的主攻方向。我国干热岩勘查工作近年来进展迅速,先后在不同地区发现了优质的干热岩资源,取得了我国干热岩资源勘查突破,但同时也存在不少勘查失败的案例。本文在分析高放射性产热型、沉积盆地型、近代火山型和强烈构造活动带型等四种类型干热岩成因模式的基础上,结合我国的地质构造背景、地热地质条件,对未来我国干热岩资源重点勘查方向及靶区进行了论述,并重点针对目前不同类型区干热岩资源勘探工程进行了梳理,简要分析了不同勘探区的选址依据、勘探过程、地温场分布及特征、前景预测等,并初步进行了经验总结,希望对我国未来干热岩资源勘查及开发工作起到借鉴作用。     

南海月平均流的计算

本文用一个二维全流方程模式,计算了南海1—12月的逐月平均流。所得的南海逐月环流的总趋势以及一些中小尺度的涡旋现象不仅与海洋观测相一致,也与已有的一些研究结果相吻合。而且,计算所得的海洋场和海面起伏场均很好地反映出南海的季节性变化特征,特别是高海暖流的存在在计算中又进一步得到了证实。文中对南海海流的机理也作了一此初步探讨。     

Magnetic connection and current distribution in black hole accretion discs

We discuss one of the possible origins of large-scale magnetic fields based on a continuous distribution of toroidal electric current flowing in the inner region of the disc around a Kerr black hole (BH) in the framework of general relativity. It turns out that four types of configuration of the magnetic connection (MC) are generated, i.e. MC of the BH with the remote astrophysical load (MCHL), MC of the BH with the disc (MCHD), MC of the plunging region with the disc (MCPD) and MC of the inner and outer disc regions (MCDD). It turns out that the Blandford–Znajek process can be regarded as one type of MC, i.e. MCHL. In addition, we propose a scenario for fitting the quasi-periodic oscillations in BH binaries based on MCDD associated with the magnetic reconnection.