Archive > Volume 45 Issue 1 > 2017,45(1):79-86 Prev Next

Comparison between Physical Processes of Triggering Two MJO Convective Events

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    Abstract:
    The observed outgoing longwave radiation (OLR) from NOAA and variables of 〖WTBX〗q,T,u,v,ω 〖WTBZ〗from ERAInterim daily data set in 2002 and 2003 are analyzed by a new method of interaction among multiple timescale components to reveal the process of moisture increasing in the boundary layer before the initiation of two MJO convective events (MJO1 and MJO2, happening in the winter of 2002). It is found that during 3 days before the two MJO convections initiated, there are the 20-90 day filtered positive moisture tendency, positive moisture anomaly and vertical ascending motion leading the MJO1 and MJO2 convections in boundary layer, which indicates that moisture increasing in the boundary layer creates the convectively unstable layer good to the initiation of MJO convections. Positive horizontal moisture advection is the main contributor to the moisture increasing in both MJO1 and MJO2, which contributed to the advection process in which intraseasonal easterly transports the larger mean background moisture to the two initiation regions. The greatest difference in the process of moisture increasing between MJO1 and MJO2 is the positive vertical moisture convection, which is much larger in MJO2 than that in MJO1, which mainly contributed to the distinct difference of the component of mean background moisture by intraseasonal vertical ascending motion between MJO1 and MJO2, because there is a larger ascending motion of 20 to 90 day time scale in MJO2 than that in MJO1

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External LinksChina Meteorological AdministrationCMA Meteorological Observation CentreChinese Academy of Meteorological SciencesBeijing Meteorological ServiceNational Satellite Meteorological Center
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