The narrow sense and applicable limit of Practical Salinity Scale 1978 (PSS78) and volumetric titration using silver nitrate to measure the salinity of non conservative oceanwater are discussed.The salinity obtained ...The narrow sense and applicable limit of Practical Salinity Scale 1978 (PSS78) and volumetric titration using silver nitrate to measure the salinity of non conservative oceanwater are discussed.The salinity obtained by electrical conductivity method and chlorinity salinity method obviously deviates from the absolute salinity( S A). The Density Salinity Scale(DSS98)proposed by the writers can be extensively used in conservative and non conservative water samples. The merits of the density salinity scale are as follows. (1)The Density Salinity Scale is only related to seawater mass and its buoyant effect, and is not influenced by the variation in seawater composition, and therefore,has high reliability,and repeatability for salinity determination. (2)The salinity values measured by the DSS98 have a conservative property.For oceanwater samples the salinity values are the same as those determined by the PSS78; for non conservative water samples(e g. samples from industrial sources),the salinity values are close to the absolute salinity values in comparison with those measured by the PSS78 and the Knudsen method. (3)For a solution with given solute mass,the solution concentration can be converted into the corresponding salinity by the Density Salinity Scale using the expansion coefficient of the solution and the calibration coefficient of the partial molar volume of the solute.展开更多
草原毛虫(Gynaephora alpherakii)是青藏高原高寒草地生态系统和畜牧业的主要害虫之一。草原毛虫幼虫监测是刻画其时空分布特征、评估致害等级及有效防控的基础。然而,受限于观测成本、效率和精度,传统监测方法无法满足大尺度、动态、...草原毛虫(Gynaephora alpherakii)是青藏高原高寒草地生态系统和畜牧业的主要害虫之一。草原毛虫幼虫监测是刻画其时空分布特征、评估致害等级及有效防控的基础。然而,受限于观测成本、效率和精度,传统监测方法无法满足大尺度、动态、定点开展草原毛虫幼虫监测的需求。本研究提出一种基于无人机的草原毛虫幼虫的高效、准确、定点、适宜大尺度开展的监测方法(Belt mode based on unmanned aerial vehicle,UAVBelt)并予以实地验证。研究结果表明,UAVBelt方法在监测效率、代表性、对草地破坏性(并克服取样障碍)及提高时效性、可预报性等方面均优于传统方法;基于具备地形跟随和变焦功能的无人机(Mavic 2 Zoom)的监测方法(Belt mode based on Mavic 2 with double optical zoom,UAVM2)在取样均一性、数据提取效率和准确性等方面更优。结合无人机自动航拍和分析系统(fragmentation monitoring and analysis with aerial photography,FragMAP),UAVM2监测方法在草原毛虫幼虫信息提取、灾害预警、高效防控等方面具有巨大的应用潜力,可为青藏高原畜牧业和生态系统可持续发展提供必要的理论和实践指导。展开更多
文摘The narrow sense and applicable limit of Practical Salinity Scale 1978 (PSS78) and volumetric titration using silver nitrate to measure the salinity of non conservative oceanwater are discussed.The salinity obtained by electrical conductivity method and chlorinity salinity method obviously deviates from the absolute salinity( S A). The Density Salinity Scale(DSS98)proposed by the writers can be extensively used in conservative and non conservative water samples. The merits of the density salinity scale are as follows. (1)The Density Salinity Scale is only related to seawater mass and its buoyant effect, and is not influenced by the variation in seawater composition, and therefore,has high reliability,and repeatability for salinity determination. (2)The salinity values measured by the DSS98 have a conservative property.For oceanwater samples the salinity values are the same as those determined by the PSS78; for non conservative water samples(e g. samples from industrial sources),the salinity values are close to the absolute salinity values in comparison with those measured by the PSS78 and the Knudsen method. (3)For a solution with given solute mass,the solution concentration can be converted into the corresponding salinity by the Density Salinity Scale using the expansion coefficient of the solution and the calibration coefficient of the partial molar volume of the solute.
文摘具有环境梯度或小尺度生境异质性的群落,a 多样性在不同尺度及不同空间位置上的测定结果将存在差异。基于甘肃省莲花山国家级自然保护区 2条长 420 m、宽 10 m样带的群落调查数据,采用分形理论和方法研究了云冷杉林和针阔叶混交林群落 a 多样性测度随空间尺度变化的效应,以及 a 多样性测度与取样尺度之间的分形关系。结果表明:1)随着取样尺度逐步扩大,云冷杉林和针阔叶混交林群落物种丰富度指数和Shannon 指数值先急剧增长后趋于平稳,表现出一定范围内尺度对样带 a 多样性测度具有强烈影响。综合物种丰富度指数和Shannon 指数尺度变化曲线的估计,云冷杉林样带 a 多样性研究比较适宜的取样尺度为 60 m,而针阔叶混交林样带为 90 m,即云冷杉林样带上比较适宜的取样尺度明显小于针阔叶混交林样带;2)针阔叶混交林样带上 a 多样性与取样尺度之间的分形关系比云冷杉林样带更趋于多变,表明针阔叶混交林物种组成的空间异质性高于云冷杉林。
文摘草原毛虫(Gynaephora alpherakii)是青藏高原高寒草地生态系统和畜牧业的主要害虫之一。草原毛虫幼虫监测是刻画其时空分布特征、评估致害等级及有效防控的基础。然而,受限于观测成本、效率和精度,传统监测方法无法满足大尺度、动态、定点开展草原毛虫幼虫监测的需求。本研究提出一种基于无人机的草原毛虫幼虫的高效、准确、定点、适宜大尺度开展的监测方法(Belt mode based on unmanned aerial vehicle,UAVBelt)并予以实地验证。研究结果表明,UAVBelt方法在监测效率、代表性、对草地破坏性(并克服取样障碍)及提高时效性、可预报性等方面均优于传统方法;基于具备地形跟随和变焦功能的无人机(Mavic 2 Zoom)的监测方法(Belt mode based on Mavic 2 with double optical zoom,UAVM2)在取样均一性、数据提取效率和准确性等方面更优。结合无人机自动航拍和分析系统(fragmentation monitoring and analysis with aerial photography,FragMAP),UAVM2监测方法在草原毛虫幼虫信息提取、灾害预警、高效防控等方面具有巨大的应用潜力,可为青藏高原畜牧业和生态系统可持续发展提供必要的理论和实践指导。
