An integrated package for subgrid convection, clouds and precipitation compatible with meso‐gamma scales

• Published in: Quarterly journal of the Royal Meteorological Society 2007-04, Vol.133 (624), p.711-730
• Main Author: Gerard, L.
• Format: Article
• Language: English
• Subjects: Earth, ocean, space; Exact sciences and technology; External geophysics; grey‐zone resolutions; local‐area modelling; Meteorology; Physics of the high neutral atmosphere; prognostic convection; prognostic microphysics
• ISSN: 0035-9009; 1477-870X
• DOI: 10.1002/qj.58

The integration into a coherent package of the main ‘moist’ parametrizations—deep convection, resolved condensation, and microphysics—of a limited‐area model is presented. The development of the package is aimed at solving efficiently the problem of combining ‘resolved’ and ‘subgrid’ condensation at all resolutions, in particular in the range between 10 km and 2 km where deep convection is partly resolved, partly subgrid. The different schemes of the package are called in cascade, with intermediate updating of internal variables, so that, for instance, the initial profiles passed to the deep‐convection scheme are already balanced with respect to resolved condensation effects. Further on, the clean separation of the contributions to the closure of the updraught and downdraught from the initial vertical profile from which they evolve prevents double counting. The convective parametrization works with a prognostic mass‐flux scheme, and acts on the resolved variables through condensation and convective transport. It detrains condensates that are added to the prognostic resolved condensates. A sensitivity study in a single‐column model, and further validation in three‐dimensional experiments at different resolutions, are presented. Copyright © 2007 Royal Meteorological Society