5–7 May 2021
virtual
Europe/Copenhagen timezone

Influence of large-scale subsidence on convective aggregation

6 May 2021, 16:00
1h 45m
virtual

virtual

Interactive presentation RCE and Processes in Deep Convective Organization RCE and Processes in Deep Convective Organization

Speaker

David Coppin (University of Auckland)

Description

A series of cloud-resolving model experiments is used to investigate the response of convection to imposed large-scale subsidence. Subsidence is favorable to convective aggregation in a non-linear fashion. In our model configuration, the radiative-convective equilibrium exhibits scattered convection and this non-aggregated stationary state exists also for weak subsidence. For large subsidence, an aggregated stationary state exists, and there is a significant range of subsidence intensity for which both aggregated and non-aggregated states co-exist. The aggregated state is, in average, drier than the non-aggregated state and therefore the drying effect of subsidence is weaker on the aggregated than on the non-aggregated state, making the former more resilient to subsidence than the latter. The aggregated state can be analyze in both two-column and moist static energy frameworks, and it appears that the main adjustment to the subsidence forcing is a reduction of the area of the convective patch. We also analyze transient experiments to quantify the contributions of the different physical processes to the aggregation or disaggregation of convection.

Primary author

David Coppin (University of Auckland)

Co-author

Dr Gilles Bellon (University of Auckland)

Presentation materials