21世纪平流层温度变化和臭氧恢复

温室气体增加和可能的臭氧恢复将是影响21世纪平流层温度变化的两个主要因素。温室气体增加的辐射效应将导致平流层变冷，而臭氧恢复将导致平流层变暖。为探讨平流层温度在这两种相反因素作用下的变化趋势，研究中使用了观测的臭氧和温度资料以及4个有代表性的IPCC AR4海气耦合的全球环流模式的模拟结果（GISS-ER、GFDL CM20、NCAR CCSM3和UKMO-HadCM3）。观测分析结果表明，在近10年来臭氧柱含量和平流层低层温度均有升高的趋势，平流层中层温度仍然延续20世纪后20年的变冷趋势。IPCC-AR4的模拟结果表明，单纯温室气体增加将造成平流层变冷。可是，在同时考虑温室气体增加和臭氧层恢复的情况下，模拟结果表明平流层中上层仍将维持变冷的趋势，而下层则存在变暖的趋势，但几个模式给出的变暖趋势有差别。UKMO-HadCM3给出的模拟结果是在3种温室气体排放情况下平流层低层均呈现较强的变暖趋势，变暖的层次可达40 hPa；GFDL-CM20和NCAR-CCSM3给出的变暖趋势较弱一些，并且变暖主要位于60 hPa以下的层次。

Stratospheric temperature changes and ozone recovery in the 21st century

Increasing greenhouse gases and likely ozone recovery will be the two most important factors influencing changes in stratospheric temperatures in the 21st century. The radiative effect of increasing greenhouse gases will cause cooling in the stratosphere, while ozone recovery will lead to stratospheric warming. To investigate how stratospheric temperatures change under the two opposite forcings in the 21st century, we use observed ozone and reanalysis data as well as simulation results from 4 IPCC-AR4 coupled oceanic and atmospheric general circulation models (GISS ER、GFDL CM20、NCAR-CCSM3 and UKMO-HadCM3). Observational analysis shows that total column ozone and lower stratospheric temperatures all show increasing in the past 10 years, while middle stratospheric temperatures demonstrate cooling. IPCC-AR4 simulations show that greenhouse forcing alone will lead to stratospheric cooling. However, with forcings of both increasing greenhouse gases and ozone recovery, the middle stratosphere will be cooled, while the lower stratosphere will be warmed. Warming magnitudes vary from one model to another. UKMO-HadCM3 generates relatively strong warming for all three greenhouse scenarios, and warming extends to 40 hPa. GFDL-CM20 and NCAR CCSM3 produce weak warming, and warming mainly exists at lower levels, below about 60 hPa. In addition, we also discuss the effect of temperature changes on ozone recovery.