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A theory of organized steady convection and its transport properties
Author(s) -
Moncrieff M. W.
Publication year - 1981
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49710745103
Subject(s) - parametrization (atmospheric modeling) , convection , kinetic energy , physics , statistical physics , classical mechanics , mesoscale meteorology , mechanics , meteorology , quantum mechanics , radiative transfer
A dynamical classification of organized convection is presented, and previously published and additional models are collated in a more general theory. the transport properties of each type are represented by flux laws, the motivation being to understand convective transports in the context of parametrization schemes for organized convection. Five distinct models, derived as analytic solutions to a general displacement equation obtained from conservation properties of the Boussinesq equations, are necessary to describe the dynamics. These models, designated propagating, steering‐level, jump, cellular and classical, have very distinctive dynamical structures, and can be combined to represent more complex types of organized convection. The propagating and steering‐level types export a significant amount of kinetic energy, momentum and entropy, while the jump and cellular types store a considerable amount of energy as work done on the environment by the pressure field. the classical type does not transport momentum, and is a representation of the classical thunderstorm in weakly sheared flow. Apart from the cellular model, although the entropy transports are broadly similar, the momentum and kinetic energy transports are very distinctive, with counter‐gradient momentum transport the rule rather than the exception. Thus by effecting organized updraught/downdraught circulations, a completely different transport problem from small‐scale cumulus and mixed‐layer convection is posed, with fundamental inferences regarding parametrization. the dynamical necessity of a mesoscale response in the cellular and propagating types suggests that this scale may, in certain cases, need to be represented explicitly in convective parametrization schemes for large‐scale models. These prototypes have been deliberately simplified for the sake of elucidating fundamental principles, and to give a dynamical basis for experimentation and generalization, through exploiting both cloud‐scale and larger‐scale numerical simulation models, as well as providing guidance in observational analyses, budget studies in particular.