南极对流层-平流层下部气候变化特征及其原因

利用南极16站30余年地面至30hPa10层月平均气温距平序列资料,采用最大熵功率谱方法,研究了南极对流层至平流层下部气候变化的长期趋势和周期性特征,并讨论了平流层(对流层)气候变化与南极臭氧总量(南半球500hPa环流)变化之间的联系。指出:南极气温具有明显的长期趋势和周期性变化;平流层下部显着变冷、对流层增暖,变化最大层高度在100、700hPa,最大降冷速率远大于增暖速率,气层稳定度趋于减弱;30、50hPa气温具有准两年周期,100hPa上下具有显着的年周期,对流层是以3.5年甚低频周期为主;对流层顶气温无显着趋势变化和周期性变化;南极最大臭氧层高度显着变冷与近15年来臭氧层损耗有关。南半球对流层中部极涡及绕极气流减弱是南极对流层气候变暖的直接原因。

ANTARCTIC CLIMATIC VARIATION IN THE TROPOSPHERE AND LOWEER STRATOSPHERE WITH CAUSES

Through agency of ground-to-30hPa 10-level monthly mean temperature anomaly series from 16 Antarctic stations and with the aid of maximument ropy power spectral technique, study is conducted of the long-term trend and periodicty of the troposphere and lower strat osphere temperature and of the connection between climatic change in the lower strat osphere (troposphere)temperature and total ozone(southern hemisphere 500 hPa circulation).Results show that Ant arctic temperature exhibit spronounced long-term trend and periodicity; appreciable cooling(w arming)occurs in the lower st rat osphere(troposphere),with maximal variation at 100 and 700 hPa,strongest cooling being by far greater than maximum warming rate and air-layer stability tending to decrease;30 and 50 hPa temperatures possess quasi-biennial period and around 100 hPa temperat ure displays not iceable annual cycle;3.5 year period is dominant as the very low frequency variation in the troposphere;tropopause temperat ure shows no pronounced change in the trend and periodicty;the height where max imum ozone layer emerges has its temperature g reat ly reduced,a fact that is associated with the layer subjected to damages in the past 15 years;the polar vort ex in the southern hemisphere troposphere and circum polar flow weakings represent a direct cause of the tropospheric warming over Antarctics.