Effects of Convective Processes on GCM Simulations of the Madden–Julian Oscillation
Open Access
- 15 January 2010
- journal article
- Published by American Meteorological Society in Journal of Climate
- Vol. 23 (2), 352-377
- https://doi.org/10.1175/2009jcli3114.1
Abstract
Weak temporal variability in tropical climates such as the Madden–Julian oscillation (MJO) is one of major deficiencies in general circulation models (GCMs). The uncertainties in the representation of convection and cloud processes are responsible for these deficiencies. With the improvement made to the convection scheme, the Iowa State University (ISU) GCM, which is based on a version of the NCAR Community Climate Model, is able to simulate many features of MJO as revealed by observations. In this study, four 10-yr (1979–88) ISU GCM simulations with observed sea surface temperatures are analyzed and compared to examine the effects of the revised convection closure, convection trigger condition, and convective momentum transport (CMT) on the MJO simulations. The modifications made in the convection scheme improve the simulations of amplitude, spatial distribution, eastward propagation, and horizontal and vertical structures, especially for the coherent feature of eastward-propagating convection and the precursor sign of convective center. The revised convection closure plays a key role in the improvement of the eastward propagation of MJO. The convection trigger helps produce less frequent but more vigorous moist convection and enhance the amplitude of the MJO signal. The inclusion of CMT results in a more coherent structure for the MJO deep convective center and its corresponding atmospheric variances.Keywords
This publication has 54 references indexed in Scilit:
- High-resolution simulations of global climate, part 1: present climateClimate Dynamics, 2003
- Simulation of the Madden–Julian Oscillation in a Coupled General Circulation Model. Part I: Comparison with Observations and an Atmosphere-Only GCMJournal of Climate, 2003
- Simulation of the Madden–Julian Oscillation in a Coupled General Circulation Model. Part II: The Role of the Basic StateJournal of Climate, 2003
- The National Center for Atmospheric Research Community Climate Model: CCM3*Journal of Climate, 1998
- On the Relationship between the Streamfunction and Velocity Potential of the Madden–Julian OscillationJournal of the Atmospheric Sciences, 1997
- The NCEP/NCAR 40-Year Reanalysis ProjectBulletin of the American Meteorological Society, 1996
- The Life Cycle of the Madden–Julian OscillationJournal of the Atmospheric Sciences, 1994
- Parameterization of moist convection in the National Center for Atmospheric Research community climate model (CCM2)Journal of Geophysical Research: Solid Earth, 1994
- A study of the diabiatic heating associated with the Madden‐Julian oscillationJournal of Geophysical Research: Solid Earth, 1991
- Interaction of a Cumulus Cloud Ensemble with the Large-Scale Environment, Part IJournal of the Atmospheric Sciences, 1974