平流层爆发性增温事件中大气准16日行星波

摘要

2014年1月上中旬高纬平流层发生弱增温事件,增温幅度约25K,纬向西风减弱并于2月初转向.行星波在平流层爆发性增温(SSW)事件产生中具有重要作用.利用北半球近东经120°链上中低纬5个流星雷达探测的风场数据,研究了此SSW事件发生前和发生期间中间层和低热层区(MLT)大气风场的行星波状况.结果显示,极区平流层增温前MLT区大气呈现出明显增强的准16日波动,增温达到最大时,16日波也最强,表明中低纬MLT区的行星波变化与SSW事件存在耦合关系.进一步利用欧洲中心平流层再分析资料数据,分析SSW期间北半球平流层的波动和零风线状况,发现平流层准16日波和零风线随时间由低纬向高纬移动,反映出16日波与SSW之间存在某种动力学联系.%A minor Sudden Stratospheric Warming (SSW) event occurred in the early and middle January of 2014.The amplitude of increasing temperature was about 25 K,and the zonal eastward wind became weaker and shifted its direction until the early February.The Planetary Waves (PW) play an important role in SSW events.Using the wind data detected by 5 meteor radars at low and middle latitude of northern hemisphere near 120°E,the PWs during this minor SSW event are studied.Results show that the enhanced quasi-16-day PW is found at Mesosphere and Lower Thermosphere (MLT) region.The enhancement of quasi-16-day waves was prior to the warming,and the quasi-16-day PW had mostly the strongest amplitude when the polar temperature reached its peak.This demonstrates the coupling between PW of low and middle latitude MLT region and SSW.Furthermore,using the reanalysis data from the European Center for Medium-range Weather Forecasts (ECMWF),the wave coupling between stratosphere and mesosphere is investigated.The band pass filtering result of the stratospheric temperature shows that quasi-16-day PW propagated from lower latitude to the pole,meanwhile the zero-wind line moved from low latitude to high latitude,The results indicate a dynamical connection between the 16-day PWs and SSW.