FY-4A多源协同监测梧州强对流的热动力演变

hermodynamic-Kinematic Evolution of Wuzhou Severe Convection Monitored by FY-4A Multi-Sensor Synergy

  • 摘要: 本研究基于风云四号A星(FY-4A)多源卫星数据,对2022年4月22日广西梧州强对流天气过程开展综合分析,重点探究卫星遥感在强对流预警中的应用价值. 研究采用水汽云图,可见光,红外增强云图,对流定量化产品和相当黑体亮温(TBB)等数据,系统揭示强对流云团的演变特征及其与极端天气的关联机制. 结果表明:对流云团发展表现为云顶亮温降低、水汽阻塞加强和动力干带演变等特征;TBB低值区(≤230 K)与强降水区域一致,当5分钟TBB递减率超过−10 K时预示短时强降水,当5分钟TBB递减率超过−30 K,冰雹范围最大;水汽等云图的大尺度分析对双偏振雷达可起到补充作用,基于云顶温度梯度的预警方法较双偏振雷达具有更优的时效性,但受限于卫星分辨率(2 km/3 min),在强对流天气监测中存在一定局限.

     

    Abstract: This study conducted a comprehensive analysis of a severe convective weather event in Wuzhou, Guangxi, on 22 April 2022, utilizing multi-source satellite data from the Fengyun-4A (FY-4A) satellite. The research focused on investigating the application value of satellite remote sensing for severe convection early warning. Employing datasets including water vapor imagery, visible light, infrared enhanced cloud imagery, quantitative convective products, and equivalent blackbody brightness temperature (TBB), the study systematically revealed the evolutionary characteristics of severe convective cloud clusters and their linkage mechanisms with extreme weather. Results indicate that the development of convective cloud clusters is characterized by decreasing cloud-top brightness temperature, enhanced water vapor blocking, and the evolution of dynamic dry intrusions. Regions with low TBB values (≤230 K) correspond well with areas of heavy precipitation. A 5-minute TBB decrease rate exceeding -10 K serves as a precursor to short-term heavy rainfall, while a decrease rate exceeding -30 K corresponds to the maximum spatial extent of hail. Large-scale analysis using water vapor and other cloud imagery effectively complements dual-polarization radar observations. An early warning methodology based on cloud-top temperature gradients demonstrates superior timeliness compared to dual-polarization radar. However, its effectiveness in severe convective weather monitoring has certain limitations due to constraints imposed by the satellite's spatial and temporal resolution (2 km / 3 min).

     

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