平流层对对流层的作用是准确评估、预测对流层气候变化的一个重要方面。其中平流层成分尤其是臭氧的变化,可以改变平流层乃至对流层的辐射平衡,从而影响平流层、对流层的热动力过程。本文从辐射、动力2个角度介绍了平流层臭氧影响对流层气候变化的若干研究进展。平流层臭氧可以通过长短波辐射的方式对对流层大气造成辐射强迫,利用大气化学气候模式可以定量计算平流层臭氧变化引起的辐射强迫,但是辐射强迫的估算受模式中辐射传输模块本身缺陷的影响存在不确定性。动力方面,平流层臭氧变化产生的辐射效应可以改变温度的垂直和经向梯度,造成波折射指数的变化,进而影响平流层甚至对流层内波的折射与反射,通过上对流层下平流层区域内的波—流相互作用,对对流层气候产生影响。另外,南极臭氧损耗可通过大气环状模影响冬春季中高纬度对流层的天气气候,但是其影响的强度大小以及物理机制仍需进一步的确认。值得注意的是,北极平流层臭氧的变化与北半球中高纬度气候变化之间的关系相比南半球要更加复杂,需要更为深入的研究。
The influence of the stratosphere on the troposphere is an important issue to accurately evaluate and predict tropospheric climate changes.Stratospheric chemical compositions,especially the stratospheric ozone,could influence the dynamic and thermal processes by changing the radiation balance in the stratosphere as well as the troposphere.Studies on the influence of the stratospheric ozone on the tropospheric climate via the radiative and dynamic processes are reviewed in this paper.The stratospheric ozone can affect the tropospheric temperature by infrared heating,and the radiative forcing of the stratospheric ozone can be calculated using Chemistry-Climate Model(CCM).However the shortages of radiation scheme in the CCM bring large uncertainties for the estimation of radiative forcing.From the perspective of dynamic processes,the variations in the stratospheric ozone can change the vertical and meridional temperature gradient and further influence the refractive index of planetary waves as well as the propagation and reflection of planetary waves in the stratosphere and even the troposphere.Thus,the climate systems in the upper troposphere and lower stratosphere are affected through wave-mean flow interactions.In addition,many previous researches have documented that ozone depletions over the Antarctic regions can influence the synoptic and climate systems during spring and winter in the middle and high latitudes in the Southern Hemisphere through the annular modes.But the quantitative contributions and physical mechanism associated with them are worthy of investigation.It should be pointed out that the relationship between the stratospheric ozone variations and climate changes in the middle and high latitudes over the Northern Hemisphere is more complicated than that over the Southern Hemisphere,which requires more researches in the future.