Hysteretic Behavior of Moist Convection

摘要

Two-dimensional moist convection was studied with a Boussinesq approximated model, where the effect of moisture is only taken into account as a flow dependent heating. To confirm the existence of the hysteretic behavior of moist convection in the presence of many horizontal motion scales, a high resolution model was investigated, taking a large number of wave components. By numerically integrating the high resolution model with a slowly varying static stability hysteretic behavior is observed as a quasi-equilibrium feature of the model. Varying the dissipation time scale and the height of the lifting condensation level shows that hysteretic behavior is most significant with a weak dissipation and a low lifting condensation level. Transient characteristics of the model were investigated, where the diurnal cycle is simulated by a time varying static stability. The sudden transition from a state of rest to a state of convection disappears if the dissipation is too weak.