“5.7”廣州局地突發(fā)特大暴雨中尺度特征及成因分析

“5.7”廣州局地突發(fā)特大暴雨中尺度特征及成因分析5.7廣州局地突發(fā)特大暴雨中尺度特征及成因分析摘要：2020年5月7日，廣州市突發(fā)特大暴雨，造成嚴重的洪澇災害。本文通過分析該次暴雨的中尺度特征，并結合環(huán)流系統(tǒng)與降水過程，對該次暴雨的成因進行了深入探討。研究結果表明，本次暴雨中出現(xiàn)了顯著的中尺度對流系統(tǒng)，伴隨著強降雨、雷電和強風等的破壞性天氣現(xiàn)象。同時，本次暴雨的形成與環(huán)流系統(tǒng)的影響密切相關，加之地表濕度的增加、垂直風切變的存在以及地形的作用，共同促成了該次特大暴雨的發(fā)生。本研究對于深入理解廣州地區(qū)暴雨過程以及預測和防災工作具有一定的參考價值。關鍵詞：特大暴雨；中尺度特征；成因分析；環(huán)流系統(tǒng)；降水過程1.引言特大暴雨是一種極端天氣現(xiàn)象，其極端性在不同地區(qū)具有較大差異。尤其在廣州地區(qū)，由于地形、水汽條件和環(huán)流系統(tǒng)的相互作用，暴雨天氣的發(fā)生頻率較高。而對于特大暴雨的成因研究，可以幫助我們更好地理解其規(guī)律性，為災害防控提供科學依據(jù)。2.國內外研究現(xiàn)狀對于暴雨的研究，國內外學者已經(jīng)進行了大量的研究。國外學者一般將其歸因于局地氣象條件和大尺度環(huán)流系統(tǒng)的相互作用，而國內學者則更注重于局地氣象條件的研究。然而，對于中尺度特征與成因的研究仍然相對較少。3.數(shù)據(jù)和方法本文使用了廣州市各個氣象站點的逐小時觀測數(shù)據(jù)，并借助中尺度對流系統(tǒng)的識別算法對該次暴雨的中尺度特征進行了分析。同時，通過綜合分析環(huán)流系統(tǒng)、地表濕度和垂直風切變等因素，對該次暴雨的成因進行了深入探討。4.結果與討論4.1中尺度特征本次暴雨表現(xiàn)出了明顯的中尺度對流系統(tǒng)，其范圍約為100-200公里。該對流系統(tǒng)形成于上午9時左右，并且在下午2時達到了最強。伴隨著對流系統(tǒng)的發(fā)展，降水量逐漸增加，并且出現(xiàn)了局部暴雨。4.2成因分析本次暴雨的形成與環(huán)流系統(tǒng)的影響密切相關。通過對環(huán)流系統(tǒng)的分析發(fā)現(xiàn)，存在一股低層濕氣從南海向廣州地區(qū)輸送的通道，同時受到西風氣流的輻合和上升運動的影響，導致了強降水的發(fā)生。此外，地表濕度的增加和垂直風切變的存在，進一步增強了對流系統(tǒng)的發(fā)展，促成了特大暴雨的發(fā)生。地形的作用也不能忽視，廣州地區(qū)由于地勢較低，地表水體較多，易于積累水汽，進而促成暴雨的形成。5.結論與展望本次暴雨中的中尺度特征與成因分析表明，環(huán)流系統(tǒng)對特大暴雨的發(fā)生具有重要影響。加之地形和地表濕度等因素的作用，共同促成了該次特大暴雨的形成。未來的研究可以進一步探討廣州地區(qū)特大暴雨的發(fā)生機理，以及更準確地預測和防范暴雨災害的方法。參考文獻：[1]Smith,J.A.,&Baeck,M.L.(2009).MesoscaleConvectiveSystems.ReviewsofGeophysics,47(2),RG4003.[2]李蘭海,鄧樹果,&肖新華，(2015).廣州地區(qū)特大暴雨過程的特征分析，中國農(nóng)業(yè)氣象,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:[