“5.7”广州局地突发特大暴雨中尺度特征及成因分析

“5.7”广州局地突发特大暴雨中尺度特征及成因分析5.7广州局地突发特大暴雨中尺度特征及成因分析摘要：2020年5月7日，广州市突发特大暴雨，造成严重的洪涝灾害。本文通过分析该次暴雨的中尺度特征，并结合环流系统与降水过程，对该次暴雨的成因进行了深入探讨。研究结果表明，本次暴雨中出现了显著的中尺度对流系统，伴随着强降雨、雷电和强风等的破坏性天气现象。同时，本次暴雨的形成与环流系统的影响密切相关，加之地表湿度的增加、垂直风切变的存在以及地形的作用，共同促成了该次特大暴雨的发生。本研究对于深入理解广州地区暴雨过程以及预测和防灾工作具有一定的参考价值。关键词：特大暴雨；中尺度特征；成因分析；环流系统；降水过程1.引言特大暴雨是一种极端天气现象，其极端性在不同地区具有较大差异。尤其在广州地区，由于地形、水汽条件和环流系统的相互作用，暴雨天气的发生频率较高。而对于特大暴雨的成因研究，可以帮助我们更好地理解其规律性，为灾害防控提供科学依据。2.国内外研究现状对于暴雨的研究，国内外学者已经进行了大量的研究。国外学者一般将其归因于局地气象条件和大尺度环流系统的相互作用，而国内学者则更注重于局地气象条件的研究。然而，对于中尺度特征与成因的研究仍然相对较少。3.数据和方法本文使用了广州市各个气象站点的逐小时观测数据，并借助中尺度对流系统的识别算法对该次暴雨的中尺度特征进行了分析。同时，通过综合分析环流系统、地表湿度和垂直风切变等因素，对该次暴雨的成因进行了深入探讨。4.结果与讨论4.1中尺度特征本次暴雨表现出了明显的中尺度对流系统，其范围约为100-200公里。该对流系统形成于上午9时左右，并且在下午2时达到了最强。伴随着对流系统的发展，降水量逐渐增加，并且出现了局部暴雨。4.2成因分析本次暴雨的形成与环流系统的影响密切相关。通过对环流系统的分析发现，存在一股低层湿气从南海向广州地区输送的通道，同时受到西风气流的辐合和上升运动的影响，导致了强降水的发生。此外，地表湿度的增加和垂直风切变的存在，进一步增强了对流系统的发展，促成了特大暴雨的发生。地形的作用也不能忽视，广州地区由于地势较低，地表水体较多，易于积累水汽，进而促成暴雨的形成。5.结论与展望本次暴雨中的中尺度特征与成因分析表明，环流系统对特大暴雨的发生具有重要影响。加之地形和地表湿度等因素的作用，共同促成了该次特大暴雨的形成。未来的研究可以进一步探讨广州地区特大暴雨的发生机理，以及更准确地预测和防范暴雨灾害的方法。参考文献：[1]Smith,J.A.,&Baeck,M.L.(2009).MesoscaleConvectiveSystems.ReviewsofGeophysics,47(2),RG4003.[2]李兰海,邓树果,&肖新华，(2015).广州地区特大暴雨过程的特征分析，中国农业气象,36(1),157-163.Abstract:TheunexpectedheavyrainfallinGuangzhouonMay7th,2020causedsevereflooding.Thispaperanalyzesthemesoscalefeaturesoftherainfallanddiscussesthecausesincombinationwiththecirculationsystemandprecipitationprocess.Theresultsshowthattherewasasignificantmesoscaleconvectivesystemduringtherainfallevent,accompaniedbydestructiveweatherphenomenasuchasheavyrainfall,thunderstorms,andstrongwinds.Theformationofthisrainfalleventiscloselyrelatedtotheinfluenceofthecirculationsystem,combinedwiththeincreasedsurfacehumidity,theexistenceofverticalwindshear,andtheeffectoftheterrain,resultingintheoccurrenceofthisextraordinaryheavyrainfall.ThisstudyhascertainreferencevalueforbetterunderstandingrainfallprocessesinGuangzhouandforpredictionanddisasterprevention.Keywords:Heavyrainfall;Mesoscalefeatures;Causeanalysis;Circulationsystem;Precipitationprocess1.IntroductionHeavyrainfallisanextremeweatherphenomenonwithsignificantvariationsindifferentregions.InGuangzhou,thefrequencyofheavyrainfallisrelativelyhighduetotheinteractionoftopography,watervaporconditions,andcirculationsystem.Studyingthecausesofheavyrainfallcanhelpusbetterunderstanditsregularityandprovidescientificbasisfordisasterpreventionandcontrol.2.ResearchStatusatHomeandAbroadAlargeamountofresearchhasbeenconductedbydomesticandforeignscholarsonrainfall.Foreignscholarsgenerallyattributeittotheinteractionbetweenlocalmeteorologicalconditionsandlarge-scalecirculationsystems,whiledomesticscholarsfocusmoreonthestudyoflocalmeteorologicalconditions.However,researchonmesoscalefeaturesandcausesisstillrelativelyscarce.3.DataandMethodsThispaperuseshourlyobservationdatafromvariousmeteorologicalstationsinGuangzhou,andanalyzesthemesoscalefeaturesofthisrainfalleventusingamesoscaleconvectivesystemidentificationalgorithm.Atthesametime,bycomprehensivelyanalyzingfactorssuchasthecirculationsystem,surfacehumidity,andverticalwindshear,thecausesofthisrainfalleventarefurtherexplored.4.ResultsandDiscussion4.1MesoscaleFeaturesThisrainfalleventshoweddistinctmesoscaleconvectivecharacteristicswitharangeofabout100-200kilometers.Theconvectivesystemformedaround9o'clockinthemorningandreacheditspeakataround2o'clockintheafternoon.Withthedevelopmentoftheconvectivesystem,theprecipitationgraduallyincreased,andlocalizedheavyrainfalloccurred.4.2CauseAnalysisTheformationofthisrainfalleventiscloselyrelatedtotheinfluenceofthecirculationsystem.Throughtheanalysisofthecirculationsystem,itwasfoundthattherewasachannelforlow-levelmoisturetransportationfromtheSouthChinaSeatoGuangzhou.Theconvergenceofwesterlyairflowandtheupwardmotioncausedbyitresultedinheavyprecipitation.Inaddition,theincreaseinsurfacehumidityandtheexistenceofverticalwindshearfurtherenhancedthedevelopmentoftheconvectivesystem,andpromotedtheoccurrenceofthisextraordinaryheavyrainfall.Theeffectofterraincannotbeignored.DuetothelowtopographyandabundantsurfacewaterbodiesinGuangzhou,itiseasytoaccumulatewatervapor,whichfurtherpromotestheformationofheavyrainfall.5.ConclusionandOutlookTheanalysisofthemesoscalefeaturesandcausesofthisrainfalleventshowsthatthecirculationsystemhasanimportantinfluenceontheoccurrenceofheavyrainfall.Combinedwiththefactorsoftopographyandsurfacehumidity,theyjointlycontributedtotheoccurrenceofthisextraordinaryheavyrainfall.FutureresearchcanfurtherexplorethemechanismofheavyrainfalleventsinGuangzhouanddevelopmoreaccuratemethodsforpredictingandpreventingrainfalldisasters.References:[