Die Entstehung tropischer Störungen

Abstract

SummaryThe mutually interacting pressure wave and diabatic heating wave originally cause the observed tropical disturbances. The equivalent barotropic models relate the tendency of vorticity with the convective heating effect directly, and so these models elucidate the roles of these mutually interacting waves on the development of observed tropical disturbances readily. The exact solution for the complex frequency adequately explains the growth and movement of tropical disturbances during summer. The results are divided into two parts 1) for the upper atmosphere 2) for the lower atmosphere. For the upper atmosphere during summer, the standing and amplifying natures of wave numbers 1 and 2 are satisfactorily interpreted. So the standing natures and the intensity variations of Atlantic trough, African high, Tibetan high, Pacific trough, and Mexican high etc. are also explained thereby. Also, the amplification and westward movement of short wave number 8 are interpreted, For the lower atmosphere during summer, the amplifications and westward movements of Carribean easterly wave, African monsoon cyclone, Indian monsoon depression, west Pacific ITCZ wave etc. are explained. Zusammenfassung Die Entstehung tropischer St6rungen

A study on Indian monsoon disturbances

“…Recently, Krishnamurti et al [3] have given some special informations about monsoon depression, showing that the amount of rainfall may be as large as 20 to 30 cm per day. Therefore, the diabatic heating effect may be several 340 A.C. Mahanti times larger than that, shown in [ 1 ]. Also, there is very sharp increase of the diabatic heating effect with height at the low level.…”

“…In the earlier study [1 ], eqs. (4) and (5) for the zonally propagating and amplifying waves have been emphasised and the frequency equation which has enabled us to obtain the growth rate and phase velocity has been obtained.…”

“…The discussions for the amplifying waves with both zonal and meridional propagation (eqs. (18) and (19) of [ 1 ]) have been discontinued after showing that the complex frequency remains un'altered. In the present study, we resume the case of amplifying waves with zonal and meridional propagation and study the following different situations.…”

“…northward movement may be explained. In this context, we have used larger values of the ratio-amplitude parameter than those used in [ 1 ] (since those values may be increased even by several times than the previous values, given in [ 1 ]). Also, we have tried to calculate the phase velocity and growth rate of hurricane depression which has wind speed 65 knots or more and wavelength 1000 km nearly.…”

“…Recently, Mahanti [ 1 ] has explained the growth rates and movements of the upper and lower level disturbances in tropics, depending on the mutual interaction of the pressure wave and diabatic heating wave. The ratio-amplitude parameter has been calculated depending on 2 to 3 cm rainfall per day, which gives about 10°C warming per day [2].…”