Tropical Intraseasonal Variability in the MRI-20km60LAGCM
IR@C-MMACS: CSIR-Centre for Mathematical Modelling and Computer Simulation, Bangalore
View Archive Info| Field | Value | |
| Title |
Tropical Intraseasonal Variability in the MRI-20km60LAGCM
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| Creator |
K, Rajendran
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| Subject |
Climate Modelling
Meteorology and Climatology |
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| Description |
Some Madden-Julian Oscillation (MJO) features were previously diagnosed in the
MRI-20km60L AGCM that uses the Arakawa-Schubert cumulus parameterization. This study continues to document the detailed characteristics of the tropical intraseasonal variability (TISV) in this model. Mean states, power spectra, propagation features, leading EOF modes, vertical structure, and seasonality associated with the TISV are analyzed using the software package provided by the US CLIVAR MJO Working Group.
Results show that the model produces the mean states in winds very realistically and in
convection comparable to observations. However, the simulated TISV is not as realistic.
It shows low amplitude in convection and low-level winds in the 30-60-day band.
Filtered anomalies have apparently standing structures. Power spectra and lag regression
of the signals do not propagate dominantly in either the eastward direction during boreal
winter or the northward direction during boreal summer. A combined EOF (CEOF)
analysis of winds and convection shows a loose coupling among these fields that cannot
sustain a TISV as prominent as that observed. In the composited phase 3 of an MJO life
cycle, the vertical moisture anomaly does not tilt westward near the convective center as
in observations, indicating that the boundary layer moisture anomaly does not lead
convection nor does it favor the eastward propagation. The weak and irregular TISV
signals suggest that improvement in convection is necessary in this model
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| Publisher |
American Meteorological Society
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| Date |
2009-04
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://cir.cmmacs.ernet.in/107/1/8526.pdf
K, Rajendran (2009) Tropical Intraseasonal Variability in the MRI-20km60LAGCM. Journal of Climate, 22 (8). ISSN 1520-0442 |
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| Relation |
http://cir.cmmacs.ernet.in/107/
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