Accessibility navigation


Departures from convective equilibrium with a rapidly-varying surface forcing

Davies, L., Plant, R. S. and Derbyshire, S. H. (2013) Departures from convective equilibrium with a rapidly-varying surface forcing. Quarterly Journal of the Royal Meteorological Society, 139 (676). pp. 1731-1746. ISSN 1477-870X

[img]
Preview
Text - Accepted Version
· Please see our End User Agreement before downloading.

1MB

It is advisable to refer to the publisher's version if you intend to cite from this work. See Guidance on citing.

To link to this item DOI: 10.1002/qj.2065

Abstract/Summary

Convective equilibrium is a long-standing and useful concept for understanding many aspects of the behaviour of deep moist convection. For example, it is often invoked in developing parameterizations for large-scale models. However, the equilibrium assumption may begin to break down as models are increasingly used with shorter timesteps and finer resolutions. Here we perform idealized cloud-system resolving model simulations of deep convection with imposed time variations in the surface forcing. A range of rapid forcing timescales from 1 − 36hr are used, in order to induce systematic departures from equilibrium. For the longer forcing timescales, the equilibrium assumption remains valid, in at least the limited sense that cycle-integrated measures of convective activity are very similar from cycle to cycle. For shorter forcing timescales, cycle-integrated convection becomes more variable, with enhanced activity on one cycle being correlated with reduced activity on the next, suggesting a role for convective memory. Further investigation shows that the memory does not appear to be carried by the domain-mean thermodynamic fields but rather by structures on horizontal scales of 5 − 20km. Such structures are produced by the convective clouds and can persist beyond the lifetime of the cloud, even through to the next forcing cycle.

Item Type:Article
Refereed:Yes
Divisions:Faculty of Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
ID Code:30996
Uncontrolled Keywords:cloud-resolving modelling; convective quasi-equilibrium; rapid forcing
Publisher:Royal Meteorological Society
Publisher Statement:This is a preprint of an article accepted for publication in the Quarterly Journal of the Royal Meteorological Society. Copyright 2013 Royal Meteorological Society.

Downloads

Downloads per month over past year

University Staff: Request a correction | Centaur Editors: Update this record

Page navigation