王叶红. 2019. 双雷达风场反演拼图在登陆台风“莫兰蒂” (1614) 强降水精细预报中的同化应用试验[J]. 气象学报, (0):-, doi:10.11676/qxxb2019.041
双雷达风场反演拼图在登陆台风“莫兰蒂” (1614) 强降水精细预报中的同化应用试验
Assimilation experiments for the application of dual-radar retrieval wind mosaics in detailed heavy precipitation forecast produced by landfall typhoon “Meranti” (1614)
投稿时间:2017-10-13  修订日期:2018-09-28
DOI:10.11676/qxxb2019.041
中文关键词:  双雷达,风场反演,同化,台风,强降水
英文关键词:Dual—radar, Wind field retrieval, Assimilation, Typhoon, Heavy precipitation
基金项目:国家自然科学基金(41405106、41675047)、福建省气象局开放式气象科学研究基金(2017K08)、厦门市科技惠民计划项目(3502Z20174052、3502Z20164080)、高原与盆地暴雨旱涝灾害四川省重点实验室开放研究基金项目(SZKT201803)
作者单位E-mail
王叶红 海峡气象开放实验室 yehongw@whihr.com.cn 
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中文摘要:
      [资料和方法]利用龙岩、漳州、泉州新一代天气雷达和厦门海沧双偏振雷达资料,采用地球坐标系下双雷达三维风场反演与拼图技术,基于天气研究和预报模式(Weather Research and Forecasting,WRF)及其资料同化系统,[目的]对登陆台风“莫兰蒂” (1614)引起的2016年9月14日—15日福建强降水过程进行了双雷达风场反演拼图资料检验及其三维变分同化对强降水精细预报影响的数值试验,[结果和结论]结果发现:(1)地球坐标系下双雷达反演风场能合理反映实际风场分布状况,其误差相对较小。相较厦门翔安风廓线雷达及厦门探空秒级测风数据,反演风风向(风速)平均绝对误差分别为7.8°(2.6 m/s)及3.4°(1.1 m/s);(2)反演风场水平方向稀疏化对同化及预报结果极为重要,过密的反演风场资料会给同化及预报结果带来负效果。文中采用18/6/2 km三重嵌套,在三重嵌套区域均进行同化以及仅在2 km区域进行同化两种情况下,均表现为当反演风场资料水平分辨率提高到0.1°时,同化分析及预报的台风环流开始受到负影响;且当反演风场资料水平分辨率越高时,负效果越明显。敏感性试验结果显示,分辨率取0.2°时数值预报效果最好;(3)以美国国家环境预报中心全球预报系统(National Centers for Environmental Prediction/Global Forecast System,NCEP/GFS) 0.5°×0.5°分析场为初值,基于三个不同起报时刻(2016年9月14日14时、14日20时及15日02时)模拟的福建境内台风内核雨带和螺旋雨带逐时演变、台风路径与强度、逐时降水TS评分和空间相关差异显著,其中14日14时起报试验效果最好;而14日20时起报试验效果最差,这与该试验初始台风大风轴风速明显偏大有关;(4)在上述3个不同起报时刻试验基础上,分别增加双雷达反演风场资料的三维变分同化后,福建境内地面风场和台风内核雨带、螺旋雨带逐时分布、逐时降水TS评分和空间相关、台风环流结构以及u、v风垂直廓线分布均有明显改善,最大正影响时效可达24 h;但仅对1—6 h时效内台风路径有所改善。
英文摘要:
      Based on Longyan, Zhangzhou, Quanzhou Doppler weather radar data and Xiamen—Haicang dual polarization Doppler radar data, dual—radar retrieved three—dimensional wind and mosaic technique in the dynamic earth coordinate, WRF (Weather Research and Forecasting) model and its data assimilation system, a set of numerical experiments are performed to investigate the impacts of three-dimensional variational assimilation of dual—radar retrieved winds upon the detailed heavy precipitation forecast caused by the landfall typhoon “Meranti” (1614) during the period of 14—15 Septembertember 2016 in Fujian province. The results indicate that: (1) Dual—radar retrieval wind in the dynamic earth coordinate can describe real wind fields reasonably, and its error is relatively small. The verifications between retrieval winds and wind profiler radar detections during the “Meranti” landfall show that the mean absolute errors of retrieval wind direction and speed are 7.8° and 2.6 m/s, respectively. The verifications between retrieval winds and Xiamen second radio-soundings show that those are 3.4° and 1.1 m/s, respectively. (2) The horizontal sparsification of retrieval winds have obvious impacts upon the assimilation and forecast results. Over—dense retrieval winds have negative effects on the assimilation and forecast results. In the case of using 18/6/2 km triple nested grid model and taking assimilation in triple nested regions and only in the inner 2 km region, the analyzed and forecasted typhoon circulation structures are negatively impacted when the horizontal resolution of retrieval wind arrives at 0.1°, and the negative effects are more obvious when the horizontal resolution of retrieval wind is higher. Sensitivity experiment results indicate that numerical forecasts comes to the best when using 0.2° horizontal resolution data. (3) Using NCEP/GFS (National Centers for Environmental Prediction/Global Forecast System) 0.5°×0.5° analysis data as model initial fields, three experiments are carried out at different initiation time, i.e. 14:00, 20:00 BT 14 and 02:00 BT 15, September 2016. It is found that the experimental results with different initiation time are obviously different when analyzing the hourly evolution modelling of typhoon inner core and spiral rain band in Fujian province, the typhoon track and intensity, the threat scores and spatial correlation coefficients of hourly precipitation. The simulation initiated at 14:00 BT 14 comes to the best. The simulation initiated at 20:00 BT 14, however, comes to the worst, which is due to the initial typhoon maximum wind core being stronger than the observation. (4) Based on the above three experiments initiated at different time, radar retrieval winds are assimilated by three—dimensional variational assimilation system. The hourly simulation of surface wind field, the typhoon inner core and spiral rain band in Fujian province, the threat scores and spatial correlation coefficients of hourly precipitation, the typhoon circulation, the vertical profiles of zonal and meridional winds are all obviously improved, and the valid time of positive effect is up-to 24 hours. For the simulation of typhoon track, the valid time of positive effect is, however, only up—to 6 hours.
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