PRELIMINARY STUDY ON THE INFLUENCE OF FY-4 LIGHTNING DATA ASSIMILATION ON PRECIPITATION PREDICTIONS
PRELIMINARY STUDY ON THE INFLUENCE OF FY-4 LIGHTNING DATA ASSIMILATION ON PRECIPITATION PREDICTIONS
复制标题
FY-4闪电资料同化对降水预报影响的初步研究
DOI：
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发表时间：
2019
影响因子：
1.2
通讯作者：
HUANG Fu-xiang
中科院分区：
文献类型：
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作者：
LIU Rui-xia;LIU Jie;PESSI Antti;HUI Wen;CHENG Wei;HUANG Fu-xiang
利用风云四号气象卫星（FY-4）上的闪电成像仪资料，研究了闪电资料的同化及其对降水预报的影响。首先对风云四号（FY-4A）闪电成像仪观测到的闪电事件进行了质量控制检查，然后从闪电分布中剔除噪声点。随后的分布与地面观测和降水的空间分布和范围更加一致。我们选择了与闪电频率密切相关的雷达反射率作为同化闪电数据的参数，并利用了Vaisala提供的美国东部大样本闪电频率和雷达反射率数据。在统计分析的基础上，得到了闪电频率与雷达反射率之间的经验关系，并建立了闪电频率与雷达反射率之间的查表。将闪电事件数据转换为雷达反射率数据，发现转换后的反射率与地面雷达观测的合成反射率具有很高的一致性。进一步将闪电资料同化到模式中，利用闪电资料对模式云分析过程进行了调整，对模式降水场进行了调整。以2017年8月8日发生在华南地区的一次暴雨天气过程为例进行数值预报试验，设计了对照试验、不同化FY-4闪电资料的试验（NoLig）和同化FY-4闪电资料的试验（Lig）进行对比分析。结果表明，同化FY-4A闪电资料后，Lig试验对降水强度、中心位置和范围的预报精度明显上级对照试验和NoLig试验，尤其是对短期（1-2 h）预报效果明显。本文的研究结果突出了FY-4闪电资料在降水预报中的应用价值和潜力。
Data from the lightning mapping imager on board the Fengyun-4 meteorological satellite (FY-4) were used to study the assimilation of lightning data and its influence on precipitation predictions. We first conducted a quality control check on the events observed by the first Fengyun-4 satellite (FY-4A) lightning mapping imager, after which the noise points were removed from the lightning distribution. The subsequent distribution was more consistent with the spatial distribution and range of ground-based observations and precipitation. We selected the radar reflectivity, which is closely related to the lightning frequency, as the parameter to assimilate the lightning data and utilized a large sample of lightning frequency and radar reflectivity data from the eastern United States provided by Vaisala. Based on statistical analysis, we obtained the empirical relationship between the lightning frequency and radar reflectivity and established a look-up table between them. We converted the lightning event data into radar reflectivity data and found that the converted reflectivity and composite reflectivity of ground-based radar observations showed high consistency. We further assimilated the lightning data into the model, adjusted the model cloud analysis process and adjusted the model hydrometeor field by using the lightning data. A rainstorm weather process that occurred on August 8, 2017, in South China was used for the numerical forecast experiment, and three experiments were designed for comparison and analysis: a control experiment, an experiment without the assimilation of FY-4 lightning data (NoLig), and an experiment with the assimilation of FY-4 lightning data (Lig). The results show that after assimilating the FY-4A lightning data, the accuracies of the intensity, central location and range of the precipitation predicted by the Lig experiment were obviously superior to those predicted by the control and NoLig experiments, and the effect was especially obvious in the short-term (1-2 hour) forecast. The studies in this paper highlight the application value and potential of FY-4 lightning data in precipitation predictions.