Effects of the quasi biennial oscillation in the tropics on interannual variations of atmosphere and chemistry in the extratropics

利用化学气候模式（MRI-CCM）和ERA-40再分析资料，研究了热带准两年振荡（QBO）对热带外大气和化学年际变化的影响。结果发现，传统的Holton-Tan解释，在平流层下部的赤道风作为中纬度行星波传播的波导不能解释冬季环流的ERA-40数据或模拟。虽然纬向风和温度的合成差异显示出轻微的但统计上显著的Holton-Tan效应，例如，在偏东的QBO条件下，平流层极涡较弱，扰动较大，EP通量诊断在中纬度平流层没有显示出更多的向极传播。相反，行星波传播更多的赤道，以及更多的向上在东风阶段的QBO。此外，还利用MRI-CCM研究了QBO的未来预测及其对热带外大气的影响。

Effects of the quasi biennial oscillation(QBO) in the tropics on interannual variations of atmosphere and chemistry in the extratropics were investigated with data of a chemistry-climate model(MRI-CCM) and the ERA-40 Reanalysis. It was found that the conventional Holton-Tan explanation that the equatorial winds in the lower stratosphere act as a waveguide for midlatitude planetary wave propagation cannot explain the winter circulation in either the ERA-40 data or the simulation. Although the composite differences in zonal wind and temperature show a slight yet statistically significant Holton-Tan effect, i. e., the stratospheric polar vortex is weaker and more disturbed under easterly QBO conditions, the EP-flux diagnostics do not show more poleward propagation in the midlatitude stratosphere. Rather, planetary waves propagate more equatorward as well as more upward during the easterly phase of the QBO. Further, future projection of the QBO and its effect on the extratropics was also investigated with the MRI-CCM.