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为了研究雷电流幅值概率分布特性及雷电流幅值累积概率曲线拟合效果,以满足防雷工程设计和雷击风险评估工作需要,根据湖北省2007—2013年雷电定位系统(Lightning Location System,LLS)监测的雷电流幅值资料,统计分析了雷电流幅值累积概率和密度分布特征。结果表明:正闪和负闪电雷电流幅值累积概率分布差异较大,负闪电雷电流幅值累积概率分布比正闪电更集中,负闪和总闪电的雷电流幅值累积概率分布曲线基本相同;雷电流幅值强度大部分集中在10~50kA。根据IEEE推荐的雷电流幅值累积概率分布表达式,拟合了不同极性的雷电流幅值累积概率分布公式。雷电流幅值小于110kA时,采用IEEE拟合公式计算的雷电流幅值累积概率与实测值间的相对误差较小;雷电流幅值大于110kA时,计算值与实测值间的相对误差随雷电流幅值的增加而增大。采用该文给出的分段修订公式,计算在110kA以上的雷电流幅值累积概率与实测值间的相对误差在2%以内。由IEEE推荐表达式拟合雷电流幅值累积概率分布和概率密度分布时,负闪和总闪电雷电流幅值累积概率分布拟合效果明显比正闪电好,其原因可能与正闪电分布特性有关。 相似文献
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为研究揭阳地区雷电流幅值特征,本文利用2017-2020年揭阳地区雷电流数据,通过数理统计和matlab拟合工具箱,研究分析了雷电流幅值时间分布规律及幅值累积概率特征。结果表明:近4年揭阳地区共发生地闪回击62806次,其中0-200 kA幅值的回击次数占比约为99.81 %,正、负地闪回击频次随雷电流幅值变化整体呈现先增加后减少趋势。正地闪回击幅值大值区月份出现在3月和11月,负地闪回击幅值大值区月份为3月和10月,随着季节的推移,正地闪回击幅值大值区的出现时段逐渐推迟;负地闪回击电流幅值的大值区多出现在00:00-10:00。对比分析了IEEE和DL/T幅值累积概率推荐公式曲线,IEEE推荐公式曲线与实际值分布曲线基本重合,并得出了揭阳地区雷电流幅值累积概率拟合公式,与实际值的误差值介于-0.006-0.0005,为揭阳地区的防雷减灾工作提供参考。 相似文献
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以山东桓台县华北集约化农业生态系统试验站小麦—玉米轮作农田生态系统为例,利用能值分析方法,对不同耕作方式(翻耕、旋耕、免耕)和秸秆还田(清茬、粉碎还田)下农田生态系统的能值利用进行了比较分析。结果表明:粉碎还田模式的可更新有机能比率比清茬的高出4~5倍,说明粉碎还田的可持续发展指数大于清茬的,有利于保护环境;耕作方式上,可持续发展指数表现为免耕的翻耕的旋耕的,说明免耕法具有明显的可持续发展优势,应适当推广。 相似文献
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单一值预报向概率预报转变的价值:
谈谈概率预报的检验和应用 总被引:7,自引:1,他引:7
基于大气系统的非线性和复杂性,加上初值和模式等本身无法避免的一些不确定性,天气预报从单一值的确定论向多值的概率论转变不但符合气象科学的实际也是更好地服务社会之必需。但是这种转变的理性思考对很多用户、甚至气象工作者自己都不是很清楚。为了帮助人们理解和加速这一转变,本文就这种转变所面临的一些普遍困惑谈一些想法。作为促成这一转变的中心技术集合预报——有关的问题已经在本文的姐妹篇中作了讨论。在本文中将主要讨论另外几个问题,即如何衡量一个概率预报的好坏?如何应用概率信息来作决策?以及为什么概率预报比单一值决定论预报更有经济价值?为了易懂,本文用浅显的说理结合举例的方式进行阐述,以便读者特别是广大预报员和用户能在实际中运用。 相似文献
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V. V. Kovalenko 《Russian Meteorology and Hydrology》2014,39(1):57-62
A possibility of obtaining steadier long-term estimates of modal values of the long-term runoff as compared with the technique based on using the system of ordinary differential equations for initial statistical moments is demonstrated using the approximation of multidimensional probability model of river runoff formation with first-order partial differential equations. 相似文献
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Qiu Jinhuan 《大气科学进展》1988,5(2):229-241
An analytical dependence of the optical depth solution to lidar equation on boundary values was con-firmed. According to the dependence this paper analyzed the sensitivity of lidar equation solutions obtained by forward and backward integration algorithms to the boundary values and quantitatively expounded an error limit to the boundary values under a given inversion accuracy. Furthermore, this paper presented a method for determination of the far-end boundary value in the case of inhomogeneous atmosphere, improving the accuracy of lidar equation solution. 相似文献
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J. Tiago de Oliveira 《Theoretical and Applied Climatology》1986,37(4):184-193
Summary The basic ideas of univariate extremes and some applications are described in the paper; some references are made to multivariate extremes and stochastic processes of extremes.
With 4 Figures 相似文献
Zusammenfassung Es werden einige grundlegende Ideen zu univariaten Extremen und ihren Anwendungen beschrieben. Multivariate Extreme und stochastische Prozesse von Extremen werden ebenfalls besprochen.
With 4 Figures 相似文献
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M. V. Bukharov 《Russian Meteorology and Hydrology》2013,38(8):515-521
Considered is a new approach to the estimation of thunderstorm probability based on satellite measurements in IR-range and synchronous forecast meteorological information. Analyzed is the conformity between the results of thunderstorm detection by different networks. Substantiated is the use of the data of WWLLN and Vaisala global networks of thunderstorm detection for assessing the correctness of satellite thunderstorm probability diagnosis. Demonstrated is the satisfactory correspondence between the data of these networks accumulated during 15 minutes and the results of thunderstorm probability diagnosis on the territory of Russia and Europe carried out using the data from three geostationary satellites. Noted is the utility of new maps of satellite thunderstorm probability diagnosis for increasing the aircraft flight safety. 相似文献
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V. F. Loginov V. S. Mikutskii G. P. Kuznetsov 《Russian Meteorology and Hydrology》2007,32(10):651-657
Methods of studying May frosts, their time dynamics, and spatial structure in Belarus are considered. The territory of Belarus was divided into western and eastern parts with the help of methods of multivariate statistical analysis, proceeding from the dynamics of a number of frost days in May. Before 1985, the number of frost days prevailed in the western part, while after 1985, in eastern Belarus. A quasi-twelve-year cyclicity is established in the dynamics of a difference between a number of frost days in May in the east and west of the country 相似文献
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Conservation actions generally benefit some groups more than others, and this inequity is thought to affect the probability of achieving conservation objectives. This has led to the common assumption that triple bottom line solutions – those that are effective, efficient, and equitable – are best and most likely to achieve each individual objective. Although this may be true, it has been little tested, and importantly lacks a conceptual foundation for understanding, predicting and evaluating how equity affects conservation outcomes. We describe types of equity relevant to conservation and explore how they may affect the probability of successfully achieving conservation outcomes. Depending on the equity type and context, the relationship between equity and conservation success varies. We find that the best conservation outcome is often achieved without perfect equity; highlighting the risk of ignoring the relationship between equity and success. We offer a conceptual foundation for better addressing this important issue in future research and application. 相似文献
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Variability and probability of annual and extreme precipitation over Serbia and Montenegro 总被引:1,自引:0,他引:1
Summary Annual precipitation over Serbia and Montenegro is studied in terms of its variability. The dependence of three selected absolute measures of variability (standard deviation, absolute mean deviation and mean absolute interannual variability) from the mean annual precipitation are examined for the area of interest. Two cases of extreme precipitation in Serbia were analysed using the gamma probability density function and some transformations. 相似文献