On wave-CISK and the evaporation-wind feedback for the Madden-Julian oscillation

B. Kirtman, A. Vernekar

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The combined effects of Kelvin wave-CISK and the evaporation-wind (E-W) feedback are proposed as a possible mechanism for the Madden-Julian oscillation. A very simple single vertical mode model has been employed to examine the effects of both these processes on moist Kelvin waves. The effects of wave-induced moisture convergence is parameterized by reducing the moist static stability, and CISK occurs when the moist static stability becomes negative. The E-W feedback in the presence of mean easterlies leads to unstable Kelvin modes. The presence of mean westerlies leads to decaying Kelvin modes. When CISK and the E-W feedback work in concert, an unstable Kelvin mode develops that has phase speeds of propagation between 5 m s-1 and 10 m s-1 for a large range of parameter values. On the other hand, the E-W feedback mechanism alone, in the case when CISK is not operating, produces the phase speeds of the observed Madden-Julian oscillation for only a very limited range of parameter values. -Authors

Original languageEnglish (US)
Pages (from-to)2811-2814
Number of pages4
JournalJournal of the Atmospheric Sciences
Volume50
Issue number16
DOIs
StatePublished - Jan 1 1993
Externally publishedYes

ASJC Scopus subject areas

  • Atmospheric Science

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