Brewer-Dobson（BD）环流在全球的辐射收支平衡中扮演着极其重要的角色，被认为是气候系统的重要组成部分。以往关于BD环流的研究大都集中于将BD环流作为一个整体进行分析，很少涉及BD环流不同分支的时空分布特征，这些分支对平流层大气成分的不同影响更没有得到足够重视。本项目拟采用多种再分析资料，观测资料结合大气化学传输模式等，详细分析过去几十年BD环流不同分支的时间变化趋势和空间变化特征，并进一步给出不同分支出现不同变化趋势的原因。在此基础上，诊断BD环流不同分支对平流层大气成分的异常变化和长期变化趋势的影响，并定量评估近些年BD环流不同分支对这些大气成分变化趋势的贡献。研究成果可能为合理评估平流层大气成分的变化提供新的参考依据，具有特色和创新。

The Brewer-Dobson (BD) circulation plays an important role in the global radiation balance and is considered to be an important part of the climate system. Previous studies have focused primarily on the whole changes of the BD circulation, but rarely involved the spatial-temporal variations of different branches of the BD circulation. The effect of different branches of the BD circulation on the stratospheric trace gases has also not drawn enough attention. With different kinds of reanalysis data, satellite data and chemical transport model, this project will analyze the spatial-temporal variations of different branches of the BD circulation over the past few decades. Furthermore, the cause of the long-term trends of different branches of the BD circulation will also be analyzed. Based on these, the influences of different branches of the BD circulation on the large anomaly and long-term trends of stratospheric trace gases are diagnosed. Finally, the project will quantify the contribution of different branches of the BD circulation to the changes of these trace gases. Those researches may provide new evidences for the reasonable assessment of the variations of stratospheric trace gases, with distinctive and novel.