What is the role of easterly waves on cyclogenesis in north Indian Ocean ?
It has been recognized since at least the 1930s that lower tropospheric westward traveling disturbances often serve as the “seedling” circulations for a large proportion of tropical cyclones. These disturbances are known as easterly waves. The waves move generally toward the west in the lower tropospheric trade wind flow. They are first seen usually in October to April. The waves have a period of about 3 or 4 days and a wavelength of 2000 to 2500 km. One should keep in mind that the “waves” can be more correctly thought of as the convectively active troughs along an extended wave train. Though, these waves are generated frequently, but it appears that the number that is formed has no relationship to how much tropical cyclone activity there is over the north Indian Ocean each year. It is currently completely unknown, how, easterly waves change from year to year in both intensity and location and how these might relate to the activity ?
