Summary
The present study is conducted in the equivalent barotropic model to study the stability of meridional wind at 200 mb level in tropics during summer. The equivalent barotropic model, which was introduced by Wiin-Nielsen [1] for midlatitude, is accepted for tropics after some possible changes. The meridional wind is found to be equivalent to a number of superposed dispersive Rossby waves, so the stability problem of meridional flow reduces to the stability problem of Rossby waves. In the present study, the stability of single Rossby wave is tested with a perturbation which gives zonal wind. It is found that the short Rossby waves are unstable, so the short Rossby waves release their kinetic energy to the zonal wind. Thus, the short waves of the spectral meridional flow release their kinetic energy to the zonal wind.
For midlatitude, Lorenz's problem regarding the instability of Rossby wave is improved using the equivalent barotropic model.
Zusammenfassung
Die Untersuchung wurde an einem äquivalenten barotropen Modell zum Studium der Stabilität des meridionalen Windes im 200 mb-Niveau im Sommer in den Tropen durch-geführt. Das von Wiin-Nielsen für mittlere Breiten eingeführte äquivalente Modell wurde mit einigen Änderungen auch für die Tropen angenommen. Es wurde gefunden, daß der meridionale Wind einer Anzahl von überlagerten Rossby-Wellen äquivalent ist, so daß sich das Stabilitätsproblem der meridionalen Strömung auf das Stabilitätsproblem von Rossby-Wellen zurückführen läßt. In der vorliegenden Untersuchung wurde die Stabilität einer Rossby-Welle mit einer Störung, die einen zonalen Wind ergibt, geprüft. Es wurde gefunden, daß kurze Rossby-Wellen instabil sind, so daß die kurzen Rossby-Wellen ihre kinetische Energie auf den zonalen Wind übertragen.
Das von Lorenz hinsichtlich der Instabilität der Rossby-Welle für mittlere Breiten gewonnene Ergebnis wurde mit dem äquivalenten barotropen Modell verbessert.
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Mahanti, A.C. The study of the instability of the meridional flow: Part 1. Arch. Met. Geoph. Biokl. A. 29, 235–247 (1980). https://doi.org/10.1007/BF02247764
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DOI: https://doi.org/10.1007/BF02247764