The Global Atmospheric Energy Cycle in TaiESM1: Present and Future.

The Lorenz Energy Cycle (LEC) in the Taiwan Earth System Model Version 1 (TaiESM1) historical simulation is calculated and compared with ERA5 to evaluate the model performance from the thermodynamic aspect. The future change of LEC is accessed by comparing the SSP5‐8.5 and historical simulations in TaiESM1. TaiESM1 reasonably simulates the global mean, seasonal cycle, and spatial patterns of the energy reservoirs with larger values in the mean energy components and smaller in the eddy energy components. The energy cycle in TaiESM1 is about 35%–45% stronger than ERA5, except from December to February. The impact of global warming on the LEC is different at the vertical levels. The influence of meridional temperature gradient change is the dominant factor in the intensity of the energy cycle, and the change in static stability only contributes to the lower troposphere. Lifting the tropopause in the tropics increases the meridional temperature gradient and produces more zonal mean potential energy (PM) in the upper troposphere. PM is the primary driver of the LEC and leads to a more active energy cycle in the upper troposphere. As the tropical tropospheric depth increases and the mid‐latitude eddy activities become more active, more (less) energy is stored in the upper (lower) troposphere, and the energy conversion processes tend to become stronger (weaker) in the upper (lower) troposphere. Plain Language Summary: The Lorenz Energy Cycle represents the atmosphere as a heat engine. TaiESM1 is a newly developed climate model. Therefore, we evaluate the model performance and future projection from the thermodynamic aspect to understand the model's overall capability and characteristics. The global mean values of energy reservoirs are in a reasonable range. Energy reservoirs have good spatial patterns and a proper seasonal cycle, but the model has a much stronger energy cycle than reanalysis data due to a stronger meridional temperature gradient. After warming, the energy cycle tends to be stronger (weaker) in the warming scenario's upper (lower) troposphere. This research shows that TaiESM1 is a reliable research tool and provides insights for future improvements for the model development team. Key Points: The newly developed TaiESM1 can simulate atmospheric energy reservoirs regarding global and seasonal means and spatial patternsThe energy cycle in TaiESM1 is 35%–45% stronger than ERA5, mainly contributed by the more active mean flows and eddiesIn the SSP5‐8.5 scenario, the energy cycle intensifies (weakens) in the upper (lower) troposphere due to changes in temperature gradient [ABSTRACT FROM AUTHOR]