轨道尺度东亚夏季风的动力反演

为了探求太阳辐射和高纬地区温度对东亚夏季风的驱动机理,用动力反演的方法建立了东亚夏季风的动力方程,为东亚夏季风的驱动机制研究提供了一种新的方法。在轨道尺度上得到如下结论: 东亚夏季风是由南极温度和太阳辐射量共同驱动的复杂非线性动力系统; 太阳辐射是驱动东亚夏季风的最重要驱动力,驱动贡献至少达到67.57%,南极温度次之,其驱动贡献达到21.58%,格陵兰温度对东亚夏季风的驱动不起作用; 太阳辐射量的增加,会驱使东亚夏季风增强; 南极温度存在一个阈值,在阈值两侧,对东亚夏季风具有不同的驱动机制; 东亚夏季风对太阳辐射驱动的响应,还部分地依赖于季风强度的背景值。

THE DYNAMIC INVERSION OF ORBITAL-SCALE EAST ASIAN SUMMER MONSOON

In centennial and millennial scales,the land-sea thermal difference caused by the valid solar radiation finally results in the strong-weak change of the East Asian summer monsoon.The conclusion has been authenticated by the numerical modeling experiment which based on the climate system model.Some literatures also show that both the northern high latitude temperature and the southern hemisphere temperature seem to have certain drive effect on the East Asian summer monsoon.Whether the high latitude temperature is one of the driving sources of the East Asia summer monsoon is still controversial.The research on the driving mechanism of the East Asian summer monsoon mainly has two aspects: one is the establishment of the monsoon records and the relevant statistical analysis.The second is numerical simulation experiment.The numerical simulation experiments can reveal the driving mechanism of the monsoon evolution by simulating the monsoon evolution process.The statistics modeling can make full use of the existing data,but can't reveal the inherent mechanism.However,the dynamics modeling emphasizes the mechanism research,but often ignores the data.The statistics-dynamics modeling combines the advantages of these two modeling,which not only makes full use of the data,but also reveals the dynamic mechanism.The dynamic inversion method is just one of the statistics-dynamic modeling.Here,based on the inversion method,we explored the mechanism that the solar radiation and high-latitude temperature drive the East Asian monsoon,which provides a new method for the East Asian monsoon driving mechanism research. The substitute index of the East Asian summer monsoon,the southern and northern high latitude temperature and the solar radiation respectively selects the δ18O data of the split jointed stalagmites from Sanbao and Hulu cave in China,the δD data from the South Pole EPICA Dome C,the δ18O data from the Greenland GRIP ice core and the solar radiation data in 65th degree of northern latitude in July.By means of the dynamic inversion analysis of the East Asian summer monsoon,the following results are obtained in the orbital scale: (1)The East Asian monsoon is a complex nonlinear dynamic system which was driven by the Antarctic temperature and the solar radiation. (2)The solar radiation is the most important driving force to the East Asian monsoon,which the contribution rate reaches at least 65.57%.The Antarctic temperature is another noticeable driving force to the East Asian summer monsoon,and its contribution rate is 21.58%.And the Greenland temperature has scarcely any contribution to the East Asian monsoon. (3)A threshold is discovered in the Antarctic temperature,each side of this threshold has different driving mechanism to the East Asian summer monsoon. (4)The increase of the solar radiation will result in the strengthening of the East Asian monsoon,vice versa.(5)The response of the East Asian summer monsoon to the solar radiation still partly depends on the temporal monsoon strength. (6)The East Asian summer monsoon's strength has dependence on its strength on the former moment.