Thermodynamics of the Madden-Julian Oscillation in a Regional Model with Constrained Moisture
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.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1029050
- Report Number(s):
- PNNL-SA-73333; JAHSAK; KP1701000; TRN: US201122%%681
- Journal Information:
- Journal of the Atmospheric Sciences, Vol. 68, Issue 9; ISSN 0022-4928
- Country of Publication:
- United States
- Language:
- English
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