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

Benjamin Kirtman, A. Vernekar

Research output: Contribution to journalArticle

9 Citations (Scopus)

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
StatePublished - 1993
Externally publishedYes

Fingerprint

Madden-Julian oscillation
evaporation
Kelvin wave
feedback mechanism
moisture
effect
speed
parameter

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

On wave-CISK and the evaporation-wind feedback for the Madden-Julian oscillation. / Kirtman, Benjamin; Vernekar, A.

In: Journal of the Atmospheric Sciences, Vol. 50, No. 16, 1993, p. 2811-2814.

Research output: Contribution to journalArticle

@article{076dfdc6d0fe411fac81d4895830c62d,
title = "On wave-CISK and the evaporation-wind feedback for the Madden-Julian oscillation",
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",
author = "Benjamin Kirtman and A. Vernekar",
year = "1993",
language = "English (US)",
volume = "50",
pages = "2811--2814",
journal = "Journals of the Atmospheric Sciences",
issn = "0022-4928",
publisher = "American Meteorological Society",
number = "16",

}

TY - JOUR

T1 - On wave-CISK and the evaporation-wind feedback for the Madden-Julian oscillation

AU - Kirtman, Benjamin

AU - Vernekar, A.

PY - 1993

Y1 - 1993

N2 - 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

AB - 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

UR - http://www.scopus.com/inward/record.url?scp=0027839217&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027839217&partnerID=8YFLogxK

M3 - Article

VL - 50

SP - 2811

EP - 2814

JO - Journals of the Atmospheric Sciences

JF - Journals of the Atmospheric Sciences

SN - 0022-4928

IS - 16

ER -