Most Earth system models do not account for important circulation changes associated with organized convections. We implement here the heating component of the Multiscale Coherent Structure Parameterization (MCSP) into the Energy Exascale Earth System Model version 1 (E3SMv1). The heating component of MCSP is represented by a second baroclinic normal mode with amplitude proportional to the vertically averaged convective heating provided by the convective parameterization. As a result of the addition of mesoscale heating, the representation of the MJO in E3SMv1 has improved and the Kelvin wave spectra were enhanced. Tropical precipitation biases near the maritime continent were reduced
The MJO is a dominant mode of sub-seasonal variability in the tropics. The MJO impacts weather and extreme weather in many parts of the world via teleconnections. The improved representation of the MJO in E3SMv1 is likely to lead to a more realistic representation of MJO impacts.
We implemented a parameterization of heating associated with mesoscale circulations in E3SMv1. This parameterization, which was previously missing from the model physics, improves the representation of the MJO, enhances Kelvin wave spectra, and reduces precipitation biases in the tropical West Pacific.