北半球冬季平流层温度和Brewer-Dobson环流对11 a太阳循环的响应

Responses of stratospheric temperature and Brewer-Dobson circulation to 11-year solar cycle in boreal winter

采用北京气候中心大气辐射模式(BCC-RAD)、日本气象厅JRA-55月平均再分析资料,研究了北半球冬季低纬度平流层上、下两个温度异常区对太阳周期的响应及其机制。结果表明,太阳活动偏强年,低纬度的上平流层温度暖异常是由臭氧短波加热异常引起的,它在中纬度的上平流层激发出异常强西风,阻碍行星波正常上传,由波破碎驱动的Brewer-Dobson环流也减弱,该环流上升支减弱的动力加热作用导致了低纬度的下平流层暖异常。

Using the radiation transfer scheme of Beijing Climate Center(BCC-RAD)and the monthly Japanese 55-year reanalysis data from Japan Meteorological Agency(JRA-55),this paper investigates the impacts of 11-year solar cycle on planetary waves and stratospheric temperature in boreal winter.Results show that during the strong solar activity years,the warm anomaly in tropical upper stratosphere is linked with the positive ozone ultraviolet heating,which strengthens westerly jet in upper stratosphere over mid-latitudes.The planetary waves are prevented to propagate to extratropical upper stratosphere where the waves break.The weak wave forcing drives a weak Brewer-Dobson circulation(BDC).The downward BDC anomaly in the tropical lower stratosphere warms the local air by the dynamical adiabatic process.