Convective quasi‐equilibrium

Abstract

[1] The concept of convective quasi-equilibrium (CQE) is a key ingredient in order to understand the role of deep moist convection in the atmosphere. It has been used as a guiding principle to develop almost all convective parameterizations and provides a basic theoretical framework for large-scale tropical dynamics. The CQE concept as originally proposed by Arakawa and Schubert (1974) is systematically reviewed from wider perspectives. Various interpretations and extensions of Arakawa and Schubert's CQE are considered both in terms of a thermodynamic analogy and as a dynamical balance. The thermodynamic interpretations can be more emphatically embraced as a homeostasis. The dynamic balance interpretations can be best understood by analogy with the slow manifold. Various criticisms of CQE can be avoided by taking the dynamic balance interpretation. Possible limits of CQE are also discussed, including the importance of triggering in many convective situations, as well as the possible self-organized criticality of tropical convection. However, the most intriguing aspect of the CQE concept is that in spite of many observational tests supporting and interpreting it in many different senses, it has never been established in a robust manner based on a systematic analysis of the cloud work function budget by observations as was originally defined.

Phenomenology of convection-parameterization closure

“…For example, if a positive CAPE (conhypothesis (cf. Yano and Plant, 2012a), it is highly questionable whether such onset ever happens. An energy cycle analysis by Yano and Plant (2012b) suggests otherwise: ensemble convection can repeat a cycle of discharge and recharge without ever being triggered and suppressed (i.e., being switched on and off).…”

Basic Concepts for Convection Parameterization in Weather Forecast and Climate Models: COST Action ES0905 Final Report

“…A review by Yano and Plant [38], completed under the present Action, elucidates the richness of this concept with extensive potential possibilities for further investigating it from various perspectives. Especially, there are two contrasting possibilities for interpreting this concept: under a thermodynamic analogy, as originally suggested by Arakawa and Schubert, or as a type of slow manifold condition (or a balance condition [39]).…”

“…In invoking homeostasis to the physical picture of atmospheric convection, one must make sure that there is a kind of isolation of a sub-system so that it does not react to an external drive. Yano et al [98] interpret Raymond's [99] thermodynamic self-regulation theory as a type of homeostasis (see also Section 6.3 of [38] for a review).…”

Sensitivity of Single-Year Seasonal Precipitation to Parameterization in the Weather Research and Forecasting (Wrf) Model

“…AS and BMJ schemes were primarily developed for tropical environment. This implementation assumes horizontal moisture and temperature homogeneity 15) , where this simplification may be valid only during JJA season in the JP case and all seasons in PH case. But, it had been pointed out that the QE hypothesis' validity extent is not obvious and lacks an observational basis 15) .…”

“…This implementation assumes horizontal moisture and temperature homogeneity 15) , where this simplification may be valid only during JJA season in the JP case and all seasons in PH case. But, it had been pointed out that the QE hypothesis' validity extent is not obvious and lacks an observational basis 15) . On the other hand, Tiedtke and KF schemes are LLC mass flux schemes based on deep convection initial development from convective initiation concept based on instability, moisture, and lift.…”