高原季风特征及其与东亚夏季风关系的研究

Discussion on the Characteristics of Plateau Monsoon and Its Relationship with East Asian Summer Monsoon

利用ERA-Interim的位势高度场、温度场和风场再分析资料,计算了1988-2017年的传统高原季风指数(Trational Plateau Monsoon Index,TPMI)和动态高原季风指数(Dynamic Plateau Monsoon Index,DPMI),分析了高原季风的空间分布特征和时间演变规律,结合东亚夏季风指数(East Asian Summer Monsoon Index,EASMI),探讨了高原季风与东亚季风的关系。研究表明:(1)高原夏季风从4月开始形成,暖性低值系统在高原上生成;6月暖性低压系统中心形成并达到最强,此时高原夏季风强度也达到最大;10月暖性闭合低压系统向东北方向移动且强度也随之减弱并退出,高原夏季风结束。(2)DPMI和EASMI具有明显的年际变化特征,在关键年高原夏季风和东亚夏季风的强度表现一致。(3)中纬度受东亚季风所影响区域的位势高度场和青藏高原区域的位势高度场均处于同一正相关区域,而且超前两个月的DPMI同EASMI的相关系数最大,表明高原夏季风对东亚夏季风具有一定的指示意义。(4)东亚夏季风经圈环流受高原温度场变化的影响而移动,高原夏季风的低压系统与高原温度场关系密切。

This paper uses ERA-Interim's geopotential height field, temperature field and wind field reanalysis data to calculate the Dynamic Plateau Monsoon Index (DPMI) from 1988 to 2017, and analyzed the spatial distribution of the plateau monsoon. The relationship between characteristics and time evolution, combined with the East Asian Summer Monsoon Index (EASMI), explores the relationship between the plateau monsoon and the East Asian monsoon. The results show that:(1) The plateau summer monsoon began to form in April, and the warm low value system was formed on the plateau. In June, the warm low-pressure system center formed and reached the strongest. At this time, the plateau summer wind intensity also reached the maximum;the warm closed low pressure in October The system moves to the northeast and the intensity decreases and exits. The plateau summer monsoon ends.(2) DPMI and EASMI have obvious interannual variation characteristics, and the intensity of the plateau summer monsoon and the East Asian summer monsoon is consistent in the key years.(3) The geopotential height field of the mid-latitude area affected by the East Asian monsoon and the geopotential height field of the Qinghai-Tibet Plateau are in the same positive correlation area, and the correlation coefficient between DPMI and EASMI in the first two months is the largest, indicating that the plateau summer monsoon pair The East Asian summer monsoon has certain indications.(4) The East Asian summer monsoon circulation is affected by the change of the plateau temperature field. The low-pressure system of the plateau summer monsoon is closely related to the plateau temperature field.