Details:

Journal Title:
Journal of Climate
Personal Author:
Wang, Lu ; Li, Tim ; Maloney, Eric ; Wang, Bin
Wang, Lu ; Li, Tim ; Maloney, Eric ; Wang, Bin Less -
Corporate Authors:
United States. National Oceanic and Atmospheric Administration. Office of Oceanic and Atmospheric Research ; Modeling, Analysis, Predictions, and Projections Program (U.S.) ; United States. National Weather Service. ; National Centers for Environmental Prediction (U.S.)
United States. National Oceanic and Atmospheric Administration. Office of Oceanic and Atmospheric Research ; Modeling, Analysis, Predictions, and Projections Program (U.S.) ; United States. National Weather Service. ; National Centers for Environmental Prediction (U.S.) Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research) ; CPO (Climate Program Office)
OAR (Oceanic and Atmospheric Research) ; CPO (Climate Program Office) Less -
Description:
This study investigates the fundamental causes of differences in the Madden–Julian oscillation (MJO) eastward propagation among models that participated in a recent model intercomparison project. These models are categorized into good and poor groups characterized by prominent eastward propagation and nonpropagation, respectively. Column-integrated moist static energy (MSE) budgets are diagnosed for the good and the poor models. It is found that a zonal asymmetry in the MSE tendency, characteristic of eastward MJO propagation, occurs in the good group, whereas such an asymmetry does not exist in the poor group. The difference arises mainly from anomalous vertical and horizontal MSE advection. The former is attributed to the zonal asymmetry of upper-midtropospheric vertical velocity anomalies acting on background MSE vertical gradient; the latter is mainly attributed to the asymmetric zonal distribution of low-tropospheric meridional wind anomalies advecting background MSE and moisture fields. Based on the diagnosis above, a new mechanism for MJO eastward propagation that emphasizes the second-baroclinic-mode vertical velocity is proposed. A set of atmospheric general circulation model experiments with prescribed diabatic heating profiles was conducted to investigate the causes of different anomalous circulations between the good and the poor models. The numerical experiments reveal that the presence of a stratiform heating at the rear of MJO convection is responsible for the zonal asymmetry of vertical velocity anomaly and is important to strengthening lower-tropospheric poleward flows to the east of MJO convection. Thus, a key to improving the poor models is to correctly reproduce the stratiform heating. The roles of Rossby and Kelvin wave components in MJO propagation are particularly discussed.
Keywords:
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Madden-Julian Oscillation Models Moisture Ocean Circulation General Circulation Models Moisture Budget
Source:
Journal of Climate, 30(10), 3743-3769.
DOI:
https://doi.org/10.1175/JCLI-D-16-0765.1
Document Type:
Journal Article
Funding:
Grant no. NA15OAR4310099
Rights Information:
Other
Compliance:
Submitted
Main Document Checksum:
[+]
urn:sha256:fc65990d9a7586b44a54e68763f736983d559e24846c4cd37b15dc0b77dd87ec
Download URL:
https://repository.library.noaa.gov/view/noaa/28384/noaa_28384_DS1.pdf
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