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Title: Thermodynamics of the Madden-Julian Oscillation in a Regional Model with Constrained Moisture

Abstract

In order to identify the main thermodynamic processes that sustain the Madden Julian Oscillation, an eddy available potential energy budget analysis is performed on a WRF simulation with moisture constrained by observations. The model realistically simulates the two MJO episodes observed during the winter of 2007-2008. The analysis shows that instabilities and damping associated with variations in diabatic heating and energy transport work in concert to provide the MJO with its observed characteristics. The results are used to construct a simplified paradigm of MJO thermodynamics. Furthermore, the effect of moisture nudging on the simulation is analyzed to understand the limitations of the model cumulus parameterization. Without moisture nudging, the parameterization fails to provide adequate low-level (upper-level) moistening during the early (late) stage of the MJO active phase. The moistening plays a critical role in providing stratiform heating variability that is an important source of eddy available potential energy for the model MJO.

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1029050
Report Number(s):
PNNL-SA-73333
Journal ID: ISSN 0022-4928; JAHSAK; KP1701000; TRN: US201122%%681
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of the Atmospheric Sciences
Additional Journal Information:
Journal Volume: 68; Journal Issue: 9; Journal ID: ISSN 0022-4928
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; DAMPING; HEATING; MOISTURE; OSCILLATIONS; POTENTIAL ENERGY; SIMULATION; THERMODYNAMICS

Citation Formats

Hagos, Samson M, Leung, Lai-Yung R, and Dudhia, Jimy. Thermodynamics of the Madden-Julian Oscillation in a Regional Model with Constrained Moisture. United States: N. p., 2011. Web. doi:10.1175/2011JAS3592.1.
Hagos, Samson M, Leung, Lai-Yung R, & Dudhia, Jimy. Thermodynamics of the Madden-Julian Oscillation in a Regional Model with Constrained Moisture. United States. doi:10.1175/2011JAS3592.1.
Hagos, Samson M, Leung, Lai-Yung R, and Dudhia, Jimy. Thu . "Thermodynamics of the Madden-Julian Oscillation in a Regional Model with Constrained Moisture". United States. doi:10.1175/2011JAS3592.1.
@article{osti_1029050,
title = {Thermodynamics of the Madden-Julian Oscillation in a Regional Model with Constrained Moisture},
author = {Hagos, Samson M and Leung, Lai-Yung R and Dudhia, Jimy},
abstractNote = {In order to identify the main thermodynamic processes that sustain the Madden Julian Oscillation, an eddy available potential energy budget analysis is performed on a WRF simulation with moisture constrained by observations. The model realistically simulates the two MJO episodes observed during the winter of 2007-2008. The analysis shows that instabilities and damping associated with variations in diabatic heating and energy transport work in concert to provide the MJO with its observed characteristics. The results are used to construct a simplified paradigm of MJO thermodynamics. Furthermore, the effect of moisture nudging on the simulation is analyzed to understand the limitations of the model cumulus parameterization. Without moisture nudging, the parameterization fails to provide adequate low-level (upper-level) moistening during the early (late) stage of the MJO active phase. The moistening plays a critical role in providing stratiform heating variability that is an important source of eddy available potential energy for the model MJO.},
doi = {10.1175/2011JAS3592.1},
journal = {Journal of the Atmospheric Sciences},
issn = {0022-4928},
number = 9,
volume = 68,
place = {United States},
year = {2011},
month = {9}
}