Comparison of the Global Energy Cycle between Chinese Reanalysis Interim and ECMWF Reanalysis

The global energy cycle is a diagnostic metric widely used to gauge the quality of datasets. In this paper, the “Mixed Space–Time Domain” method for diagnosis of energy cycle is evaluated by using newly developed datasets—the Chinese Reanalysis Interim (CRAI) and ECMWF Reanalysis version 5 (ERA5), over a 7-yr period (2010–16) on seasonal and monthly timescales. The results show that the energy components calculated from the two reanalysis datasets are highly consistent; however, some components in the global energy integral from CRAI are slightly larger than those from ERA5. The main discrepancy in the energy components stems from the conversion of baroclinic process, whereas the dominant difference originates from the conversion from stationary eddy available potential energy to stationary eddy kinetic energy (CES), which is caused by systematic differences in the temperature and vertical velocity in low–mid latitudes of the Northern Hemisphere and near the Antarctic, where there exist complex terrains. Furthermore, the monthly analysis reveals that the general discrepancy in the temporal variation between the two datasets also lie mainly in the CES as well as corresponding generation and dissipation rates.