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Publication Date
1 October 2023

Improving Climate Variability Simulation in E3SM by Incorporating the Dynamical Effect of Large-Scale Vertical Motion on Convection

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A convective mass flux adjustment approach is proposed to represent the dynamical effects of large-scale circulation (vertical motion) on convection in E3SM. 


The convective mass flux adjustment approach improves the representation of the interaction between convection and large-scale circulation, resulting in improved simulations of both climate variability and mean climate without the mean-state-variability trade-off issue.


The representation of convection in global climate models is one of the most challenging scientific issues. Many deficiencies in precipitation and climate variability simulations and uncertainties in climate change projections can be traced to the poor representation of convection. Recent observational studies suggest that large-scale vertical motion plays important roles in deep convection development. We propose a convective mass flux adjustment (MAdj) approach to represent the effects of large-scale vertical motion on convection in Energy Exascale Earth System Model version 2 (E3SMv2). With MAdj, convection is enhanced (suppressed) when there is large-scale ascending (descending) motion at the planetary boundary layer top. The coupling of convection with large-scale circulation significantly improves the simulation of climate variability in E3SMv2 across multiple scales from diurnal cycle, convectively coupled equatorial waves, to Madden-Julian Oscillations. Improving the simulation of climate variability through modifying convection parameterization usually causes degradations of the mean climate. The MAdj approach does not degrade the climatology simulations. It actually slightly improves the climatology simulations in precipitation, clouds, radiation, circulation, temperature, and moisture fields.

Point of Contact
Xiaoliang Song
Scripps Institution of Oceanography
Funding Program Area(s)
Additional Resources:
NERSC (National Energy Research Scientific Computing Center)