| 基于梯度的500 hPa槽线天气系统自动分析方法 |
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| 引用本文： | 颜长建,胡文东,张春梅,王式功,杨有林,任浩,吕昌伟.基于梯度的500 hPa槽线天气系统自动分析方法[J].应用气象学报,2016,27(6):741-749. |
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| 作者姓名： | 颜长建 胡文东 张春梅 王式功 杨有林 任浩 吕昌伟 |
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| 作者单位： | 1.北方民族大学计算机科学与工程学院，银川750021 |
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| 基金项目： | 资助项目： 公益性行业（气象）科研专项（GYHY201206005，GYHY201306002，GYHY201206004），国家自然科学基金项目（61461002） |
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| 摘 要： | 利用位势高度场资料，针对500 hPa高空槽线天气系统，以天气学定义及其图形学特征分析为基础，在保持天气动力学理论约束的同时，提出基于位势高度梯度进行槽线天气系统自动分析的方法。面向各级气象台站的天气预报业务，利用气象信息综合分析系统 (MICAPS) 第4类位势高度格点数据资料，经过梯度计算、垂线确定、方向划分、邻域对比、节点初选、噪声判别、分类滤除、聚类分析、轴向平均等步骤，解决了一系列相关技术问题，完成了西风槽和横槽两类槽线系统自动分析的程序开发。近年宁夏寒潮强降温等过程的分析试验表明，该算法稳定可靠，中高纬度地区槽线分析能力更强，运行效率进一步提高。
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| 关 键 词： | 梯度向量 槽线 高空天气系统 自动分析 |
| 收稿时间： | 2016-03-16 |
Auto analysis of Trough System at 500 hPa Based on Gradient Algorithm |
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| Institution: | 1.College of Computer Science and Engineering, Beifang University of Ethnics, Yinchuan 7500212.College of Atmospheric Science, Chengdu University of Information Technology, Chengdu 6102253.Ningxia Meteorological Information Center, Yinchuan 750002 |
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| Abstract: | As the forecast products are increasing rapidly and the efficiency of manual process remains pretty low at present, the demand for intelligent assistant computer system of weather forecast is very urgent. It is the fundamental way to improve the automatic level of operational forecast in order to release the working pressure for detail forecast. The study on auto-analysis technology of weather systems is conducted as it is the key to build an intelligent forecast computer software with the thinking way of human kind. Based on synoptic notion and graphic features of trough system, under the guidance of computer graphics theory, trough system at 500 hPa are analyzed.The mathematic relations between gradient of geopotential height, its perpendicular direction and the nodes of trough system are proven by analysis of trough system conception, synoptic and graphics characteristics. The algorithm of trough system auto-analysis is developed under the strict constrain of atmospheric dynamic theory taking gradient of geopotential height as key element, and searching the relative minimal in its perpendicular direction within an optimal neighborhood which is determined by contrastive analysis. A set of software is developed using the geopotential height field of European Centre for Medium-Range Weather Forecasts at 500 hPa in format 4 of MICAPS which is the operational standard of China Meteorological Administration to meet the need of forecast centers at all levels of the country. The technical problems such as gradient calculating, direction zoning, neighborhood designating, primary nodes selecting, noise filtering, cluster analyzing are solved. Some fake troughs and over flow points can be identified with positioning according to the synoptic principals and basic experience, while the indices of density and location of primary nodes are applied to eliminate different noises, which concentrated in some certain areas. The multiple trough lines are merged by clustering and axial direction averaging. The auto-analysis technology and process of both westerly trough and traverse trough lines are developed and products are output in format 14 of MICAPS for forecasters. The algorithm and corresponding software system of auto-analysis of troughs is evaluated with parameters such as offset, length and general inclination angle. Recent experiments on cold wave samples in Ningxia show that the algorithm and the relevant software are stable, the effect in general is satisfying, and the method shows a better performance, especially in areas of middle and high latitudes. Through trail run, the efficiency of trough auto-analysis is improved further, and shortages of contour pursuing method are eliminated. |
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| Keywords: | gradient vector trough line weather system auto analysis |
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