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The stability of monsoon depression

Mahanti, AC (1981) The stability of monsoon depression. Archives for Meteorology, Geophysics, and Bioclimatology Series A, 30 (1-2). pp. 39-53.

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The object of the present paper is to study the stability of a monsoon depression which is a low level wave disturbance over the Indian region during summer. The stability of a wave disturbance depends intimately on the phase velocity. Again, the phase velocity of Rossby-gravity wave does not explain the phase velocity of a monsoon depression. Thus, knowing that the convective activity plays an important role in the development of a monsoon depression, one modifies the phase velocity of zonally propagating Rossby-gravity waves, i. e. one obtains the modified dispersion relation considering the effect of convective heating in the equivalent barotropic model which is derived for the low levels in tropics. The modified dispersion relation explains the phase velocity of monsoon depression. Beyond the limiting stage, there is no further depression of the central pressure. So, it is essential to study the stability of a monsoon depression at the limiting stage. The stability analysis shows that the monsoon depression is neutral (i. e.; does not break down) as long as there is convective activity. But the monsoon depression becomes unstable (i. e.; breaks down) if the convective activity ceases. In the latter case, one obtains a possible stream of zonal wind.

Item Type: Article
Additional Information: Copyright of this article belongs to Springer-Verlag
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 10 Apr 2015 09:59
Last Modified: 10 Apr 2015 09:59

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