Deep Convection Triggering by Boundary Layer Thermals. Part I: LES Analysis and Stochastic Triggering Formulation - École polytechnique Accéder directement au contenu
Article Dans Une Revue Journal of the Atmospheric Sciences Année : 2014

Deep Convection Triggering by Boundary Layer Thermals. Part I: LES Analysis and Stochastic Triggering Formulation

Résumé

This paper proposes a new formulation of the deep convection triggering for general circulation model convective parameterizations. This triggering is driven by evolving properties of the strongest boundary layer thermals. To investigate this, a statistical analysis of large-eddy simulation cloud fields in a case of transition from shallow to deep convection over a semiarid land is carried out at different stages of the transition from shallow to deep convection. Based on the dynamical and geometrical properties at cloud base, a new computation of the triggering is first proposed. The analysis of the distribution law of the maximum size of the thermals suggests that, in addition to this necessary condition, another triggering condition is required, that is, that this maximum horizontal size should exceed a certain threshold. This is explicitly represented stochastically. Therefore, the new formulation integrates the whole transition process from the first cloud to the first deep convective cell and can be decomposed into three steps: (i) the appearance of clouds, (ii) crossing of the inhibition layer, and (iii) deep convection triggering.

Domaines

Climatologie
Fichier principal
Vignette du fichier
[15200469 - Journal of the Atmospheric Sciences] Deep Convection Triggering by Boundary Layer Thermals. Part I LES Analysis and Stochastic Triggering Formulation.pdf (1.38 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-01083240 , version 1 (12-11-2021)

Licence

Paternité

Identifiants

Citer

Nicolas Rochetin, Fleur Couvreux, Jean-Yves Grandpeix, Catherine Rio. Deep Convection Triggering by Boundary Layer Thermals. Part I: LES Analysis and Stochastic Triggering Formulation. Journal of the Atmospheric Sciences, 2014, 71 (2), pp.496-514. ⟨10.1175/JAS-D-12-0336.1⟩. ⟨hal-01083240⟩
214 Consultations
58 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More