Multiscale Coherent Structure Parameterization for Organized Moist Convection

Lagrangian-based nonlinear dynamical models are utilized as heat and momentum transport modules in a new multiscale coherent structure parameterization (MCSP) that represents slantwise overturning by organized moist convection. In gray-zone nomenclature, traditional cumulus parameterization represents sub-grid convection and the dynamical models approximate organized transport. In other words, this paradigm does not replace traditional convective parameterizations but it adds organized propagating convection - a widely observed process that is missing from contemporary global climate models. The dynamical models approximate regimes of convective organization embedded in the April 2009 MJO during the Year of Tropical Convection (YOTC) virtual global field-campaign simulated by the WRF model with a 1-km grid. Transports by squall-lines, mesoscale convective systems, superclusters and equatorial waves are found to be remarkably scale-invariant or self-similar. The MCSP approach will be summarized, and the sensitivity of the large-scale atmospheric circulation to MCSP in the Community Atmosphere Model (CAM 6) reported.