Impact of microphysics and convection schemes on the mean-state and
variability of clouds and precipitation in the E3SM Atmosphere Model
- Christopher Ryutaro Terai,
- Shaocheng Xie,
- Xiaoliang Song,
- Chih-Chieh Chen,
- Jiwen Fan,
- Guang J. Zhang,
- Jadwiga H. Richter,
- Kobby Shpund,
- Wuyin Lin,
- Jean-Christophe Golaz,
- Vincent E Larson,
- Mitchell W Moncrieff,
- Yunpeng Shan,
- Chengzhu Zhang,
- Kai Zhang,
- Yuying Zhang
Jadwiga H. Richter
National Center for Atmospheric Research (UCAR)
Author ProfileJean-Christophe Golaz
Lawrence Livermore National Laboratory (DOE)
Author ProfileMitchell W Moncrieff
National Center for Atmospheric Research (UCAR)
Author ProfileAbstract
Skillful representation of tropical variability and diurnal cycle of
precipitation has remained a challenge in global atmosphere models, and
often improvements in the variability lead to degradation in the
mean-state. Here, we introduce a configuration of the E3SM Atmosphere
Model with a new microphysics scheme and several enhancements to the
deep convective scheme that improves the variability while keeping the
mean-state climatology largely unchanged. The new configuration improves
various modes of convectively-coupled equatorial waves, with increased
strength of Kelvin waves and more coherent eastward propagation of the
Madden Julian Oscillation from the Indian Ocean to the central Pacific
Ocean. The same configuration also improves both the phase and amplitude
of the diurnal cycle of precipitation, particularly over the continental
United States in the boreal summer and over Tropical land regions.
Previous studies have shown that, individually taken, some of the deep
convective enhancements can improve certain aspects of the variability,
and here we show that combining their effects can lead to robust
improvements in the variability. This model configuration can form the
basis for future studies to examine the response of tropical and diurnal
variability under various climate states and their relationships with
other modes of variability.