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arXiv 1302.0893stat.APphysics.ao-ph
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用Enhancement模式输出统计量作概率定量降水预报

Probabilistic Quantitative Precipitation Forecasting Using Ensemble Model Output Statistics

Michael Scheuerer

摘要:

动力预报集合的统计后处理是天气预报的重要组成部分。在这篇文章中,我们提出了一个后处理方法,生成完整的预测概率分布的降水积累的集合模型输出统计(EMOS)的基础上。我们模拟降水量的广义极值分布,左删失为零。这种分布允许在原始尺度上模拟降水,而无需事先转换数据。可以导出其连续秩概率得分的封闭形式表达式,并且允许计算高效的模型拟合。我们讨论了我们的方法,结合进一步的统计特征的空间变异性的降水量在感兴趣的位置附近的扩展。建议的EMOS方法应用于每日18小时的预测6小时累积降水在德国在2011年使用的COSMO-DE集合预报系统由德国气象局。它产生校准和尖锐的预测分布,并与扩展的逻辑斯谛回归和贝叶斯模型平均,这是最先进的降水后处理方法相比,毫不逊色。邻域信息的纳入进一步提高了预测性能,并证明是一个有用的策略,占位移误差的动态预测的概率预测框架。

英文摘要:

Statistical post-processing of dynamical forecast ensembles is an essential component of weather forecasting. In this article, we present a post-processing method that generates full predictive probability distributions for precipitation accumulations based on ensemble model output statistics (EMOS). We model precipitation amounts by a generalized extreme value distribution that is left-censored at zero. This distribution permits modelling precipitation on the original scale without prior transformation of the data. A closed form expression for its continuous rank probability score can be derived and permits computationally efficient model fitting. We discuss an extension of our approach that incorporates further statistics characterizing the spatial variability of precipitation amounts in the vicinity of the location of interest. The proposed EMOS method is applied to daily 18-h forecasts of 6-h accumulated precipitation over Germany in 2011 using the COSMO-DE ensemble prediction system operated by the German Meteorological Service. It yields calibrated and sharp predictive distributions and compares favourably with extended logistic regression and Bayesian model averaging which are state of the art approaches for precipitation post-processing. The incorporation of neighbourhood information further improves predictive performance and turns out to be a useful strategy to account for displacement errors of the dynamical forecasts in a probabilistic forecasting framework.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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