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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 was 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 found 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. 相似文献
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FY-4A卫星是我国首次星载闪电成像仪的静止气象卫星,其采用的可重载型FPGA芯片可连续在2ms时间,按像元完成针对400×600像元的多帧闪电信号数据处理,实时生成闪电数据及地标观测数据,并具有在轨软件上注更新配置功能。由于近地空间环境复杂,因此FPGA属于单粒子翻转敏感器件,需要采用多种手段进行单粒子翻转防护。在FY-4地面应用系统工程建设中,根据FPGA单粒子翻转对闪电探测产品所造成影响的不同,结合闪电事件数据逻辑关系、系统资源等情况,设计并在地面系统中部署了单粒子检测程序,实现了FPGA单粒子翻转异常自动辨识;根据闪电观测任务特点、闪电探测产品恢复时效性要求,同时采取自动判别与自动发令、动态刷新与定时刷新、软件复位与硬件复位等多种单粒子翻转防护综合措施,实现了FPGA单粒子翻转自动恢复。通过以上工作,目前FY-4A闪电成像仪已经有效地减少了单粒子翻转效应对闪电探测产品的影响。 相似文献
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The Lightning Mapping Imager (LMI) equipped on the FY-4A (FengYun-4A) geostationary satellite achieves lightning positioning through optical imaging and has the advantages of high temporal resolution, high stability, and continuous observation. In this study, FY-4A LMI lightning event, group and flash data from April to August 2018 are selected, and their quality are assessed through qualitative and quantitative comparison with the ground-based Advanced Time of Arrival and Direction system (ADTD) lightning observation network data and the American International Space Station (ISS) lightning imaging sensor (LIS) data. The results show that the spatial distributions of FY-4A lightning are consistent with those of the ground-based ADTD and ISS LIS. The temporal variation in FY-4A lightning group frequency is consistent with that of ADTD stroke, which reflects that FY-4A LMI can capture the lightning occurrence in inland China. Quantitative statistics show that the consistency rate of FY-4A LMI and ISS LIS events is relatively high but their consistency rate is lower in terms of lightning group and flash data. Compared with the lightning observations by the ISS LIS and the ground-based ADTD, FY-4A LMI reports fewer lightning events in the Tibetan Plateau. The application of Tibetan Plateau lightning data requires further processing and consideration. 相似文献
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静止卫星闪电探测对强对流天气的实时监测和预警具有重要意义,然而大量虚假闪电信号的存在却对闪电探测结果造成了很大影响。文章主要研究静止卫星闪电探测中的虚假信号滤除算法,以提高闪电数据分析结果的准确性。根据虚假闪电信号产生的原因和形态特征,对现有滤除算法进行系统的分析、归纳和总结。研究表明,目前的算法有各自的针对性,不同算法通常针对特定的噪声源起到过滤作用。未来发展方向,一是从仪器本身特点及其工作环境出发,探索适合于我国静止卫星闪电成像仪的虚假信号滤除算法;二是设计更加通用高效的算法,保证闪电观测的实时性和连续性;三是重视算法精度评估,并以此不断改进和完善算法。 相似文献
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