Recent changes of the general circulation in the stratosphere, and its relation to the tropospheric general circulation

通过卫星资料分析和数值模拟，研究了平流层和对流层大气环流的近期变化。根据英国气象局的平流层分析资料，首先分析了20世纪90年代和80年代3月气温和纬向风的纬向平均差异。我们可以看到北极平流层下部的降温幅度为10K，而北极上平流层的升温幅度为10K级。在高纬度地区，15m/S量级的极地夜间急流也有相应的加强。为了研究臭氧消耗对大气环流的影响，利用大气环流模式进行了数值模拟。在北极臭氧消耗实验中，获得了北极平流层下部的降温和平流层上部的增暖。这种冷却导致了极地夜间急流的加强。这些变化与观察结果一致。降温是由于臭氧耗尽导致太阳紫外线加热减少所致，而变暖是由于下沉运动增强而产生的绝热加热所致。在接下来的研究中，还需要进一步的实验来排除实验中出现的平流层突然变暖S的污染。

Recent changes of the general circulation in the stratosphere and the troposphere are investigated by satellite data analyses and numerical simulation. Zonal-mean differences of the temperature and zonal wind for March between 1990s and 1980s are firstly examined on the basis of stratospheric analyses of the UK Meteorological Office. We can see a cooling of order 10K in the North polar lower stratosphere and a warming of order 10K in the North polar upper stratosphere. The corresponding intensification of the polar night jet of order 15 m/s is also seen in high latitudes. These tendencies are considered to be due to the ozone depletion in 1990s.In order to investigate effects of ozone depletion on the general circulation, numerical simulation by using a general circulation model is performed. In Arctic ozone depletion experiment, a cooling in the North polar lower stratosphere and a warming in the North polar upper stratosphere are obtained. The cooling brings about the intensification of the polar night jet. These changes are consistent with observations. The cooling is caused by the decrease of solar UV heating due to the ozone depletion, while the warming is caused by adiabatic heating due to the enhancement of downward motion. In subsequent studies, further experiments are required to exclude the contamination of stratospheric sudden warming s occurring in the experiments.