基于动力反演方法的亚洲季风机制探讨

The Exploring of the Asian Monsoon Driving Mechanism Based on Dynamical Inversion Method

为探求董哥洞石笋δ18O值所指示的亚洲季风的驱动机制,用非线性动力反演的方法建立亚洲季风的动力方程。研究发现:董哥洞石笋δ18O值所指示的季风为印度季风,印度季风系统是由南极温度和其他驱动因子共同驱动的复杂非线性动力系统;太阳活动、北极温度和青藏高原温度对印度季风起稳定作用,太阳活动越强烈,稳定作用越弱;北极温度和青藏高原温度越高,稳定作用越弱;印度季风背景值对下一刻印度季风起稳定作用,且强度越大,稳定作用也就越强。

The monsoon driving mechanism is a hot spot in the quaternary global change research, where the international academia has been paid close attention. As early as in 1686, Halley has put forward that the heat differences caused by the sun between the marine and terrestrial bring about the monsoon. With the deepening of the research, different driving factors are proposed one after another, such as the solar activity, the mechanical force and thermal effect of the Qinghai-Tibet Plateau, ENSO, the temperature of the south and north poles, the migration of the intertropical convergence zone, the thermohaline circulation and so on in which the solar activity and the thermohaline circulation are widely accepted. Cave stalagmites oxygen isotope is one of the most important high-resolution alternative indexes of palaeoclimate. Especially in the region strongly affected by the monsoon, the change of the values of stalagmite δ18O is often taken as the index of ancient monsoon intensity. The Asian monsoon is an important part of the global climate system. Usually the Asian monsoon can be divided into East Asia monsoon and Indian monsoon, but the two monsoon regions have no clear boundary. So it is hard to verdict which monsoon the stalagmite collected from this convergence zone represents. Dongge cave is just located in the convergence zone, as is mentioned above,and which monsoon the stalagmite δ18O value of Dongge Cave represents is still controversial. By means of the dynamic inversion analysis of the Asian monsoon, the following results are obtained: 1) The stalagmites δ18O value of Dongge Cave is more likely to represent the Indian monsoon. The Indian monsoon system is a complex nonlinear dynamic system driven by the Antarctic temperature and other factors. 2) The solar activity plays a negative feedback stabilizing role in the Indian monsoon system. The stronger the solar activity is, the weaker the stabilization role it plays will be. The temperature of the Qinghai-Tibet Plateau and the North Greenland plays a negative feedback stabilizing role in the Indian monsoon system. The higher the temperature of the Qinghai-Tibet Plateau and the North Greenland is,the weaker the stabilization role it will be. 3) The Indian monsoon's strength depends on its strength of the former moment.