Basedonmonthlyrainfalldatafrom80stationsofChinafortheperiodofJanuary1951—February1985analysedintermsofthemaximumentropyspectrumandEEOF(extendedempiricalorthogonalfunction)techniques,thespatialandtemporalfeaturesofquasi-biennialoscillation(QBO)intherainfallareinvestigatedinadetailedmanner,withsomeresultsofinterestacquired.HighlyevidentistheQBOinrainfalloverChina,especiallythemidandlowerreachesoftheChangjiangRiver,theNEsideoftheQinghai-XizangPlateau,NorthChina,thesouthernpartofNEChina,areassouthoftheChangjiangRiverandoftheNanlingmountainregion,andmostofXinjiang.ThespatialwavedescribedbythefirstandsecondeigenvectorsofEEOFforeasternChinaisatypeofwavetravellingfromNEtoSW,indicatingthecycleofpatterns(inthesouthtonorthdirection):dryness(D)-wetness(W)-dryness(D)→southernW-northernslightD→W-D-W→southernD-northernslightW→D-W-Dagain,withthefloodedregionbetweentheChangjiangandHuangheRiversfortheD-W-DoccurrenceandwiththeChangjiangRiverasthepisionforthesouthernW-northernslightDhappening.Thethirdandfourtheigenvectorsshowastandingwave-likefeatureforthesameeasternpart,indicatingthecycleofD-W-D→transition→W-D-W→transition→D-W-D,again,wherethetransitionmeansthegeneralweakeningofdroughtandfloodingandtheirsubsequentreversaldevelopment.Theamplitudesofthetimecoefficientsofthefirsttwoeigenvectorsareoppositeinthetrendoftheirchangestothoseofthenexttwoandshowaperiodof10—14years.
