Publication Abstracts

Tromeur and Rossow 2010

Tromeur, E., and W.B. Rossow, 2010: Interaction of tropical deep convection with the large-scale circulation in the MJO. J. Climate, 23, 1837-1853, doi:10.1175/202009JCLI3240.1.

To better understand the interaction between tropical deep convection and the Madden-Julian Oscillation, tropical cloud regimes are defined by cluster analysis of International Satellite Cloud Climatology Project (ISCCP) cloud top pressure — optical thickness joint distributions from the D1 dataset covering 21.5 years. An MJO index based solely on upper-level wind anomalies is used to study variations of the tropical cloud regimes. The MJO index shows that MJO events are present almost all the time; instead of the MJO event being associated with "on or off" deep convection. it is associated with weaker or stronger mesoscale organization of deep convection. Atmospheric winds and humidity from NCEP/NCAR reanalysis 1 are used to characterize the large-scale dynamics of the MJO; the results show that the large-scale motions initiate an MJO event by moistening of the lower troposphere by horizontal advection. Increasingly strong convection transports moisture into the upper troposphere, suggesting a reinforcement of the convection itself. The change of convection organization shown by the cloud regimes indicates a strong interaction between the large-scale circulation and deep convection. The analysis is extended to the complete atmospheric diabatic heating by precipitation, radiation and surface fluxes. The wave organizes stronger convective heating of tropical atmosphere which results in stronger winds, while there is a only passive response of the surface, directly linked to cloud radiative effects. Overall, our results suggest that an MJO event is an amplification of large-scale wave motions by stronger convective heating, which results from a dynamic re-organization of scattered deep convection into more intense mesoscale systems.

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BibTeX Citation

@article{tr07100z,
  author={Tromeur, E. and Rossow, W. B.},
  title={Interaction of tropical deep convection with the large-scale circulation in the MJO},
  year={2010},
  journal={J. Climate},
  volume={23},
  pages={1837--1853},
  doi={10.1175/202009JCLI3240.1},
}

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RIS Citation

TY  - JOUR
ID  - tr07100z
AU  - Tromeur, E.
AU  - Rossow, W. B.
PY  - 2010
TI  - Interaction of tropical deep convection with the large-scale circulation in the MJO
JA  - J. Climate
VL  - 23
SP  - 1837
EP  - 1853
DO  - 10.1175/202009JCLI3240.1
ER  -

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