Solar influence on the troposphere and oceans through stratospheric processes

本研究的目的是通过进行观测分析和数值模式实验，论证太阳通过平流层动力学过程对对流层和海洋的影响，并确定其机制。利用气象研究所(MRI)的化学气候模式和柏林自由大学(FUB)的大气环流模式，研究了赤道QBO在平流层中的作用，以及太阳对对流层的影响随QBO的不同位相的不同而不同。在MRI和FUB模式中使用相同的平流层动量强迫，通过一个协调模式实验证明了平流层经向环流的变化对对流层垂直运动的影响。耦合海洋模式实验为了了解太阳变化引起的平流层环流变化对对流层和海洋的影响，利用MRI海洋耦合模式进行了动量强迫实验。结果表明，在太阳常数不变的情况下，全球年平均温度可变化约0.5K.3。利用再分析资料进行的观测研究表明，印度洋地区的季风环流受太阳活动周期引起的平流层经向环流变化的影响。这进一步导致了印度洋偶极子模式与太平洋地区厄尔尼诺/南方涛动之间关系的调整。作为平流层对赤道对流活动的影响修正的一个例子，展示了平流层主要变暖后的卷云覆盖和降水。国际合作SPARC化学和动力过程对太阳的影响工作组(Solaris)成立，并于2006年10月与我们的合作者在美国国家大气研究中心组织了第一次会议。

The purpose of the present study is to demonstrate the solar influence on the troposphere and oceans through stratospheric dynamical processes and to identify its mechanism by conducting observational analyses and numerical model experiments.1. Atmospheric model experimentsThe role of the equatorial QBO in the stratosphere and the difference of the solar impact on the troposphere according to the phase of the QBO were shown by using a Meteorological Research Institute (MRI) chemical climate model and Free University of Berlin (FUB) atmospheric general circulation model. The impact of the change of the stratospheric meridional circulation on the vertical motion of the troposphere was demonstrated by a coordinated model experiment by using the same stratospheric momentum forcings in the MRI and FUB models.2. Coupled ocean model experimentTo understand the impact of the stratospheric circulation change due to the solar variation on the troposphere and oceans, a momentum forcing experiment is conducted using a MRI coupled ocean model. It was shown that without a change in the solar constant, globally averaged annual mean temperature can be changed about 0.5K.3. Observational studyBy using reanalysis data, the monsoon circulation over the Indian Ocean region was shown to be influenced through change in stratospheric meridional circulation due to the solar cycle. This further lead to a modulation of the relationship between the Indian Ocean Dipole mode and the El Nino/Southern Oscillation in the Pacific sector. As an example of the stratospheric impact modification of the equatorial convective activity, cirrus cloud coverage and precipitation following a stratospheric major warming were shown.4. International cooperationSPARC working group on the solar influence through chemical and dynamical processes (SOLARIS) was formed and its first meeting was organized with our collaborators at U.S. National Center for Atmospheric Research in October 2006.