Characteristics of Soliton with Dynamic Constraints on its Existence / Propagation in Tropical Easterly Wave

The study concerns the propagation of easterly wave (EW) at tropics as west-moving soliton more steady both in form and velocity as evidenced in the dynamic framework. Under the impact of different circulation patterns over the regions of western Pacific trade wind, South-Asia monsoon and their transition, such a soliton becomes tapering off during its westward movement and degrading to a common dispersive wave on the whole, followed by disintegra-tion when striking the South-China Sea monsoon segment, thereby indicating that the sea sector is inaccessible to the soliton. When no monsoon trough is present over the South Asian monsoon area around 30oN or the monsoon de-pression is shallow, it is likely to have west-travelling soliton, which suggests the incursion of the EW into the South-Asian monsoon region.