Quasi-90-day oscillation observed in the MLT region at low latitudes from the Kunming meteor radar and SABER

(整期优先)网络出版时间:2019-02-12
/ 1
Observationsofaquasi-90-dayoscillationinthemesosphereandlowerthermosphere(MLT)regionfromApril2011toDecember2014arepresentedinthisstudy.Thereisclearevidenceofaquasi-90-dayoscillationintemperaturesobtainedfromtheKunmingmeteorradar(25.6°N,103.8°E)andSoundingoftheAtmosphereusingBroadbandEmissionRadiometry(SABER),aswellasinwindobservedbytheKunmingmeteorradar.Thequasi-90-dayoscillationappearstobeaprominentfeatureinthetemperaturesandmeridionalwindtidesandpresentsquiteregularcyclesthatoccurapproximatelytwiceperyear.Theamplitudesandphasesofthequasi-90-dayoscillationintheSABERtemperatureshowafeaturesimilartothatofupward-propagateddiurnaltides,whichhaveaverticalwavelengthof~20kmabove70km.Intheloweratmosphere,asimilar90-dayvariabilityispresentedinthesurfacelatentheatfluxandcorrelateswiththetemperatureintheMLTregion.Similartothequasi-90-dayoscillationintemperature,a90-dayvariabilityofozone(O3)isalsopresentintheMLTregionandisconsideredtobedrivenbyasimilarvariabilityintheupwardly-propagateddiurnaltidesgeneratedintheloweratmosphere.Moreover,the90-dayvariabilityintheabsorptionofultraviolet(UV)radiationbydaytimeO3intheMLTregionisaninsitusourceofthequasi-90-dayoscillationintheMLTtemperature.