Ship and Island Based Radar Observations in the Dynamics of the Madden-Julian Oscillation Project (DYNAMO)

Colorado State University, Fort Collins CO

Investigators

Abstract

The Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign is the US component of an international experiment in late 2011/early 2012 in the Indian Ocean, the Cooperative Indian Ocean Experiment on Intraseasonal Variability (CINDY2011). The overarching goal of DYNAMO is to expedite understanding of processes key to MJO initiation over the Indian Ocean and to improve simulation and prediction of the MJO. The field campaign will include multiple radars, atmospheric sounding sites, a research aircraft, multiple research vessels, and oceanic measurements. The three main hypotheses of DYNAMO are: 1) Deep convection can be organized into an MJO convective envelope only when the moist layer has become sufficiently deep over a region of the MJO scale; the pace at which this moistening occurs determines the duration of the pre-onset state, 2) Specific convective populations at different stages are essential to MJO initiation, and 3) The barrier layer, wind- and shear-driven mixing, shallow thermocline, and mixing-layer entrainment all play essential roles in MJO initiation in the Indian Ocean by controlling the upper-ocean heat content and SST, and thereby surface flux feedback Under this award a C-band Doppler radar will be deployed on the research ship, R/V Roger Revelle. The radar will be one of several participating in DYNAMO. Collectively the radars will monitor and characterize precipitating convection associated with MJO initiation. The radar data will be used to diagnose heating profiles -- the mechanism by which deep convection contributes to large scale forcing. The radar observations also will be used to validate large scale and cloud resolving model simulations of the MJO. Specifically, the PI will investigate issues relative to improving predication of the MJO initiation including: * Understanding the relationship between convective development and moistening of the atmosphere. * Characterizing the detailed nature of convection over the tropical Indian Ocean and how convective and stratiform precipitation contribute to diabatic heating. * Validation of large scale and cloud resolving models. The broader impacts of the work include the involvement of multiple graduate students in field research, and the contribution to the broader goals of the DYNAMO campaign to improve understanding of tropical convection, the predictability of the MJO, and downstream effects of the MJO on weather in the United States and other areas.