夏季是深对流多发的季节,深对流在STE(Stratosphere Troposphere Exchange,对流层平流层交换)过程中起着重要作用。对20052012年夏季我国及周边地区的深对流统计发现,2009年深对流发生的次数较少,2010年深对流发生的次数较多。通过拉格朗日输送模式对2009年和2010年夏季的大气运动状态进行模拟并统计分析,发现30°N以南和以北的地区具有明显不同的平流层对流层交换特征,30°N以北我国及周边地区TST(Troposphere to Stratosphere Transport,对流层向平流层输送)和STT(Stratosphere to Troposphere Transport,平流层向对流层输送)较为活跃,30°N以南远没有30°N以北地区活跃,但其净输送量却大致相当。在30°N以南,68月净输送是对流层向平流层输送。在30°N以北,6月净输送是平流层向对流层输送,78月净输送是对流层向平流层输送。比较深对流出现较少的2009年夏季和深对流出现较多的2010年夏季的TST和TST-STT,发现2010年68月这3个月的TST和TST-STT总量都超过2009年,表明2010年夏季我国及周边地区对流层向平流层的输送和净输送都强于2009年,与深对流活动的多少可能表现出正相关。
英文摘要:
Stratosphere-troposphere exchange(STE) is a process not only involving transport from the troposphere to stratosphere,but also from the stratosphere to troposphere. STE is very important to the variation of water vapor and atmospheric chemical compositions. Correspondingly,it also plays an important role in the radiation balance and climate changes in the global climate system. Deep convection occurs frequently in summer. The strong upward flow in deep convective cloud can transport the atmosphere of the lower troposphere quickly to the upper troposphere,and even to the lower stratosphere. Thus,it is very important in the process of STE. To date,this conclusion has been reached largely with the help of aircraft observations.