13D.4 Heating and moisture profiles in high resolution simulations of the Madden Julian Oscillation: What the coarse resolution experiments are missing

Thursday, 19 April 2012: 2:15 PM
Masters E (Sawgrass Marriott)
Marcela Ulate, Univ. of Miami/RSMAS, Miami, FL

The Madden Julian Oscillation is one of the most difficult tropical features to capture in numerical weather prediction (NWP) and global climate models (CM) due to convective and dynamic feedback mechanisms, as well as the propagation of the organized mesoscale convection associated with it, and its movement along the equator. The MJO is considered a bridge between weather scales and climate scales. Several studies have shown that Global Climate Models (GCM) and Regional Numerical Models (RNM) fail to reproduce the MJO at coarse resolution. This failure is attributed to the representation of convection by cumulus parameterization schemes, resolution, cumulus and planetary boundary layer scheme interactions and mean climate representation. Therefore high resolution simulations constitute an important guidance to understand the properties of this oscillation in depth. A MJO case of study during October-December 2009 was simulated using four different spatial scales: 100Km, 50Km, 36Km, 12Km and 4Km over the East Indian Ocean. Vertical heating and moisture profiles from the model simulations were obtained and compared for the different experiments in order to compare the missing characteristics in the lower resolution simulations, which are present in the high resolution simulations. The different spatial scales produce characteristic precipitation patterns, which are linked to their respective heating moisture vertical distribution. Numerical experiments results are also compared with observational data from the recent Dynamics of the Madden Julian Oscillation (DYNAMO) field campaign.

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