On the hysteretic behaviour of moist convection

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Abstract
A study of two-dimensional moist convection has been performed with a Boussinesq-approximated model, where the effect of moisture is only taken into account as a flow-dependent heating. We first investigate the characteristics of the model in a conditionally unstable stratification. Then by numerically integrating the model equations with a slowly varying static stability, we have also observed hysteretic behaviour as a quasi-equilibrium feature of the model. When the time scale of static stability changes is comparable to reality (12 h), the transition from a state of rest to finite amplitude convection is much quicker than the reversed process. This behaviour is directly related to the hysteresis phenomenon and gives a qualitative understanding of the dynamics of moist convection on a diurnal timescale. DOI: 10.1111/j.1600-0870.1988.tb00344.x