**NOTE Special Day, Time, and Room**
David Neelin ||
UCLA ||
Title: The transition to strong convection -- Rethinking convective quasi-equilibrium ||
Abstract: Climate models currently have considerable difficulty simulating precipitation changes, despite the fact that rainfall is one of the most critical climate variables. Convective quasi-equilibrium (QE) has for several decades stood as a key postulate for parameterization of the impacts of moist convection at small scales upon the large-scale flow. There are now unprecedented data sets for variables related to moist convection and rainfall. Borrowing tools used for critical phenomena in other systems in which a large number of interacting elements undergo a transition provides new types of observational constraint. Besides producing a remarkable collapse of precipitation statistics, linkages can be provided between the scaling of precipitation variance, power law spatial correlations and mesoscale convective systems. The dependence on temperature and moisture of the critical point for the onset of convection can be quantified in terms of entrainment of lower tropospheric moisture. Long tails of the distribution of water vapor create relatively frequent excursions above criticality with associated strong precipitation events. Taken together, these observations put a new twist on how we should think about interaction of convection with large-scale flow that appears compatible with stochastic convective parameterization approaches. ||
Host: Brian Tang