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arXiv 1609.04103physics.ao-phcs.CVphysics.geo-phstat.AP
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基于实时再分析数据的机器学习临近预报方法

A Machine Learning Nowcasting Method based on Real-time Reanalysis Data

College of Information Science and Engineering, Ocean University of China(中国海洋大学信息科学与工程学院);Institute of Urban Meteorology, China Meteorological Administration(中国气象局城市气象研究所);National Center for Atmospheric Research(国家大气研究中心);National Meteorological Center, China Meteorological Administration(中国气象局国家气象中心)

Lei Han, Juanzhen Sun, Wei Zhang, Yuanyuan Xiu, Hailei Feng, Yinjing Lin

摘要:

尽管在过去几十年中取得了显著进展,但对流风暴临近预报仍然是一个挑战,因为大多数临近预报系统都是基于雷达反射率的线性外推,而没有太多考虑其他气象场。变分多普勒雷达分析系统(VDRAS)是一种先进的对流尺度分析系统,能够通过同化多普勒雷达观测数据来提供三维风、温度和湿度的分析。尽管可能有用,但如何使用这些字段来改进临近预报仍然是一个悬而未决的问题。在这项研究中,我们提出的结果,从我们的第一次尝试开发一个支持向量机(SVM)框为基础的nOWcasting(SBOW)方法下的机器学习框架,使用VDRAS分析数据。SBOW的设计要点如下:1)将研究域划分为多个位置固定的小盒子,将临近预报问题转化为一个问题,即:30分钟后盒子里会出现大于35分贝的雷达回波吗?2)精心构造了包含时间趋势和周围环境资料的基于框的时空特征; 3)首先使用基于框的构造特征训练SVM分类器,然后使用训练好的分类器进行预测。与复杂昂贵的专家系统相比,SBOW的上述设计允许系统小型、紧凑、简单、易于维护和扩展且成本低。实验结果表明,SBOW在不使用复杂的跟踪算法的情况下,能够较好地预测风暴的移动趋势和发展。

英文摘要:

Despite marked progress over the past several decades, convective storm nowcasting remains a challenge because most nowcasting systems are based on linear extrapolation of radar reflectivity without much consideration for other meteorological fields. The variational Doppler radar analysis system (VDRAS) is an advanced convective-scale analysis system capable of providing analysis of 3-D wind, temperature, and humidity by assimilating Doppler radar observations. Although potentially useful, it is still an open question as to how to use these fields to improve nowcasting. In this study, we present results from our first attempt at developing a Support Vector Machine (SVM) Box-based nOWcasting (SBOW) method under the machine learning framework using VDRAS analysis data. The key design points of SBOW are as follows: 1) The study domain is divided into many position-fixed small boxes and the nowcasting problem is transformed into one question, i.e., will a radar echo > 35 dBZ appear in a box in 30 minutes? 2) Box-based temporal and spatial features, which include time trends and surrounding environmental information, are elaborately constructed, and 3) The box-based constructed features are used to first train the SVM classifier, and then the trained classifier is used to make predictions. Compared with complicated and expensive expert systems, the above design of SBOW allows the system to be small, compact, straightforward, and easy to maintain and expand at low cost. The experimental results show that, although no complicated tracking algorithm is used, SBOW can predict the storm movement trend and storm growth with reasonable skill.

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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