Understanding the Effects of Convective Momentum Transport on Climate Simulations The Role of Convective Heating

• Published in: Journal of climate Vol. 21; no. 19; pp. 5034 - 5047
• Main Authors: Song, Xiaoliang, Wu, Xiaoqing, Zhang, Guang Jun, Arritt, Raymond W.
• Format: Journal Article
• Language: English
• Published: Boston, MA American Meteorological Society 01.10.2008
• Subjects: Atmosphere; Atmospheric circulation; Changes; Circulation; Climate; Climate change; Climate models; Climatology; Climatology. Bioclimatology. Climate change; Convection; Convective heating; Convective momentum transport; Earth, ocean, space; Exact sciences and technology; External geophysics; Feedback; Fluid circulation; General circulation models; Geophysics. Techniques, methods, instrumentation and models; Heating; Meridional circulation; Meteorology; Momentum; Momentum transport; Parameterization; Physics; Radiation; Simulation; Simulations; Studies; Transport; Tropical climates; Tropical environments; Vertical velocities; Wind effects; Zonal winds; feedback; Atmospheric convection; Momentum transfer; General circulation models; sensitivity analysis; Climate models; Forcing; atmospheric circulation; heat transfer
• ISSN: 0894-8755; 1520-0442
• DOI: 10.1175/2008JCLI2187.1

A simplified general circulation model (GCM), consisting of a complete dynamical core, simple specified physics, and convective momentum transport (CMT) forcing, is used to understand the effects of CMT on climate simulations with a focus on the role of convective heating in the response of circulation to the CMT forcing. It is found that the convective heating dominates the meridional circulation response and dynamical processes dominate the zonal wind response to the CMT forcing in the tropics; the simplified model reproduces some of the key features of CMT-induced circulation changes observed in the full GCM in the tropics. These results suggest that the CMT-induced zonal and meridional circulation changes in the tropics in the full GCM are dominated by dynamical processes and the convective heating, respectively. Inclusion of the CMT in the model induces a marked change in convective heating, which negatively correlates with the change in vertical velocity, indicating the existence of CMT-induced convective heating–circulation feedback. The sensitivity experiment with the removal of mean convective heating feedback demonstrates that the convective heating affects the response of the meridional circulation to the CMT forcing through the CMT-induced convective heating–circulation feedback.