吴剑坤,陈明轩,秦睿,高峰,张宇,闫雪瑾,宋林烨. 2019. 变分回波跟踪算法及其在对流临近预报中的应用试验[J]. 气象学报, (0):-, doi:10.11676/qxxb2019.062
变分回波跟踪算法及其在对流临近预报中的应用试验
The variational echo tracking method and its application test in convective storm nowcasting
投稿时间:2019-03-21  修订日期:2019-06-25
DOI:10.11676/qxxb2019.062
中文关键词:  临近预报,中值滤波,雷达回波,变分回波跟踪算法,交叉相关法
英文关键词:Nowcasting, Median filter, Radar echo, Variational echo tracking method, Tracking radar echoes by correlation method
基金项目:国家自然科学基金
作者单位E-mail
吴剑坤 北京城市气象研究院 jkwu@ium.cn 
陈明轩 北京城市气象研究院 mxchen@ium.cn 
秦睿 北京城市气象研究院 rqin@ium.cn 
高峰 北京城市气象研究院 fgao@ium.cn 
张宇 广东海洋大学海洋与气象学院 zhangyu_meteo@163.com 
闫雪瑾 河北省气象台 kandher@163.com 
宋林烨 北京城市气象研究院 lysong@ium.cn 
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中文摘要:
      [目的]目前业务上0-1h对流天气临近预报仍旧以客观外推为主,采用不同外推算法,得到雷达回波以及降水的外推临近预报。本文以业务应用为目标,开展变分回波跟踪算法在强对流天气临近预报中的应用研究。[资料和方法]利用京津冀地区的8部新一代多普勒天气雷达逐6分钟雷达组网拼图资料,选取了2016-2018年夏季发生在京津冀地区的18个典型对流个例,开展了变分回波跟踪算法和交叉相关法的0-1h临近预报对比试验及检验评估。与传统的交叉相关法相比,变分回波跟踪算法采用变分技术求解雷达回波运动矢量场,在计算中使用了两个严格的约束条件,运用迭代法进行求解,其得到的运动矢量场更为准确。[结果] 结果表明,变分回波跟踪算法要优于传统的交叉相关法,给出的30、60min内雷达回波的形状、位置及强度的外推预报和实况更为接近,定量检验评分更高:[结论] 1)京津冀地区4次典型对流天气临近预报对比试验表明,和交叉相关法相比,变分回波跟踪算法可以更好地预报出未来1h内雷达回波的位置、形态和强度。2)通过对18个典型对流个例定量检验,发现当雷达回波阈值为35dBZ和45dBZ时,无论是30min还是60min外推预报,变分回波跟踪算法的命中率(POD)和临界成功指数(CSI)都明显高于交叉相关法,而误警率(FAR)更低;而分天气类型定量检验时发现,绝大多数天气类型,变分回波跟踪算法外推效果优于交叉相关法。
英文摘要:
      The objective extrapolation forecast is the main method for 0-1 hour convective storm nowcasting. Radar echo extrapolation was performed by using the 6 minute interval radar mosaics obtained from the radar images of 8 multi-radars in Beijing-Tianjin-Hebei region. A comparative study of two extrapolated forecasts of eighteen typical convective precipitation events occurred in Beijing-Tianjin-Hebei region from 2016 to 2018 was conducted. Compared with the tracking radar echoes by correlation method, the variational echo tracking method utilizes variational technique to compute the motion vector fields, and uses two strict constraints to get a better motion vector field. The results indicated that the variational echo tracking method performed better in prediction of the radar echo pattern, echo location, and echo intensity at 30- and 60-min forecast lead times: 1) A comparative study of the two forecasts of four precipitation events in Beijing-Tianjin-Hebei region was conducted. The results indicated that the radar echo location, the echo pattern and echo intensity produced by the variational echo tracking method were closer to the real observation within one hour. 2) Quantitative evaluation of the two forecasts for the eighteen typical convective precipitation events was conducted. Compared with the tracking radar echoes by correlation method, the probability of detection and the critical success index of the 30- or 60-min extrapolated forecast of echoes larger than 35 dBZ or 45 dBZ produced by the variational echo tracking method were higher, meanwhile the false alarm rate was lower. Also, a quantitative evaluation classified by the weather type indicated that the variational echo tracking method performed better than the tracking radar echoes by correlation method in most weather types.
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