Spatial Variability of Tropospheric Water Vapor and Convective Cloud Systems in DYNAMO

One of the most challenging problems in predicting MJO initiation over the Indian Ocean is the onset of the large-scale convective activity. Although it has been hypothesized that deep tropospheric moisture layer is a key for enhanced convection, connective cloud systems themselves are the main sources of tropospheric water vapor about the planetary boundary layer. Satellite observations shows that dry air advection on the synoptic scale seem to play an important role in suppression of convection. However, the interactive processes between convective cloud systems and their large-scale environmental moisture on various scales, e.g., equatorial waves, are not well understood. This study aims to better understand the coherent spatial variability of water vapor and convective clouds systems over the Indian Ocean. An objective cloud cluster tracking analysis using hourly METEOSAT IR data, satellite observed water vapor and total precipitable water (TPW), and GPS dropsondes deployed from the NOAA WP-3D aircraft during the Dynamics of MJO (DYNAMO) field campaign in November-December 2011 are used to provide a four-dimensional description of the multi-scale variability of water vapor and convective cloud systems in relation to the MJO initiation process including both convective suppressed and active phases over the Indian Ocean.