Coupling between leading modes in the troposphere-stratosphere interaction

关于平流层的研究是从纬向平均值及其偏差及其相互作用的框架下进行的。然而，有许多情况无法从这个框架中解释，因此需要一个新的框架。它是时间平均（非均匀带状场）及其偏差的框架。本研究是该框架下的首次综合研究。特别是目前还没有从这个角度进行数值研究，因此本研究在国际上尚属首次。对流层和平流层耦合的数据分析表明：对流层中的太平洋-北美模式（PNA）垂直传播到平流层，引起波数1 （W1）模式。PNA在对流层的主导地位通过W1模态的激发放大了平流层的环状模态。在某些情况下，这种耦合会导致突然变暖。这些序列明显不同于AO。其次，通过数值模拟，我们成功地模拟了对流层和平流层之间优势波数不同的现象。为了取得成功，非均匀层状油田是必不可少的。此外，对流层PNA经W1与平流层AM的耦合可以用时间积分模式模拟。我们进一步研究了对流层主导模态的真实性。结果表明，北大西洋涛动（NAO）和PNA虽然是对流层中独立的主导振荡，但北大西洋涛动的出现明显是由于北大西洋涛动和PNA的空间相关性。这一结论验证了我们的方法，即PNA和NAO是在对流层处理的。本文还研究了突变变暖的可预测性。因此，我们表明，由波数2或3引起的突然变暖比由波数1引起的变暖更难预测。

Studies about the stratosphere have been performed from the framework of the zonal mean and deviations from it, and their interaction. However, there are many cases that cannot be explained from this framework, and thereby a new framework is needed. It is the framework of time mean (non-uniform zonal field) and deviations from it. The present study is the first comprehensive research from this framework. In particular, no numerical study from this standpoint has been done, therefore this research is the first in the world.Data analyses about the coupling between the troposphere and stratosphere show the followings : The Pacific-North American pettern (PNA) in the troposphere vertically propagates into the stratosphere, causing the wavenumber 1 (W1) pattern. The dominance of the PNA in the troposphere via the excitation of the W1 mode amplifies the annular mode in the stratosphere. In some cases, this coupling causes sudden warmings. These sequences are clearly different from the AO.Next, by using numerical models, we successfully simulate phenomena in which dominant wavenumbers are different between the troposphere and stratosphere. For this success, a non-uniform zonal field is indispensable. Furthermore, the coupling from the PNA in the troposphere via W1 to the AM in the stratosphere can be simulated by a time integration model.We further proceed to the study about the reality of dominant modes in the troposphere. The conclusion is that although the North Atlantic Oscillation (NAO) and PNA are independent, dominant oscillations in the troposphere, the AO apparently appears due to the spatial correlation of the NAO and PNA. This conclusion verifies our approach that the PNA and NAO are treated in the troposphere.The predictability of the sudden warming is also studied. As a result, we show that sudden warmings caused by wavenumbers 2 or 3 are more difficult in their prediction than those caused by wavenumber 1.