The Space-Time Wave Propagating Decomposition And Principle Time-Scale Analysis And Their Application In Investigating The ISO

Since the Intraseasonal Oscillation was first documented by Madden and Julian,this phenomenon has intrigued many atmospheric scientists and oceanographers all over the world.For many scientists,it is well known that the Intraseasonal Oscillation is one dominant component of the global atmosphere.It influences the variability of rainfall over the Pacific islands,in the monsoon regions of Asia and Australia,along the west coast of North America,in South American,and in Africa.It modulates the genesis of tropical cyclones in the Pacific Ocean and the Caribbean Sea and affects equatorial surface winds in the Atlantic Ocean.It may influence the evolution of El Nino-Southern Oscillation(ENSO).Owing to its connection to these and other weather and climate systems,it is important and necessary to investigate the characteristics of the Intraseasonal Oscillation and its relationship with the weather and climate systems.In this paper,based on wave propagation theory,we propose a new analysis method:Space-Time two-dimensional wave propagation decomposition method (STWPD).We investigate the characteristics of the Intreaseasonal Oscillation and its relationship with ENSO and the flood of Jiang Huai basin,using the new method. Meanwhile,a new method is proposed to determine the principle time scale,in view of persistent period.The major results are as follows:(1)Based on the wave propagation theory,we propose a new analysis method: STWPD method.Then,we test and verify the accuracy and practicability of this method using the ideal function.The results show that this method is valid and feasible.(2)Using STWPD method,we investigate the characteristics of the Intraseasonal Oscillation in tropics.It is shown that our results using this new method are same with that of traditional method.The results suggest that this new method is also valid and feasible for the actual data.(3)Using STWPD method,we investigate the relationship between the MJO and ENSO.The results show that the MJO influence the evolution of El Nino and La Nina.Meanwhile,the El Nino and La Nina also modulate the genesis of the MJO.(4)Using STWPD method,we investigate the ISO of the East Asian Monsoon Region and its connection to the flood of Jiang Huai basin.In 1998,the Yangtze River Basin flood,the eastern propagating and western propagating of ISO are all appear and arrive the Yangtze River Basin at the same time.In 2003,the Hwai River Valley flood,the remarkable difference is that the eastern propagating of ISO is absent by comparison with that in l998.(5)Anther important content of this paper is that,we propose a new method to determine the important time scale in view of persistent period.It is Principle Time-scale analysis(PTSA).Then using the ideal function and climate indices; we test and verify the accuracy and practicability of this method.The results show that this method is valid and feasible.Furthermore,we give a global distribution of principle time-scale of ISO using this method.