Abstract: The Arctic Oscillation (AO) and Antarctic Oscillation (AAO) are important modes that typically affect atmospheric circulation and temperature changes outside tropical areas, and they are considered significant drivers of the internal variability of climate systems. Based on China’s CRA40 reanalysis dataset and using ERA5 reanalysis data as a reference, this paper presents a statistical analysis of the spatiotemporal variations of the AO and AAO during 1989—2020 and the pattern of atmospheric circulation during strong and weak years of oscillation, thus verifying the applicability of CRA40 for analyzing the AO and AAO. The results show that: (1) the master mode of geopotential height based on CRA40 presents the zonal distribution characteristics of reverse variation in middle-high latitudes, which is consistent with the ERA5 reanalysis data; (2) throughout the analysis period, there is a significant correlation between the oscillation index based on CRA40 and that of the National Oceanic and Atmospheric Administration; (3) in strong (weak) years of oscillation indicated by CRA40, the sea-level pressure and temperature at high latitudes exhibit negative (positive) anomalies, the wind field is cyclonic (anticyclonic), and the distribution of each element field at middle latitudes is the opposite of that at high latitudes; and (4) the mean zonal wind in the strong and weak oscillation years identified by CRA40 exhibits a zonal teleconnection with alternating positive-negative distribution and a barotropic structure. The analysis indicates that CRA40 effectively reflects the spatiotemporal distribution and structure of atmospheric circulation associated with the AO and AAO.

Key words: CMA’s atmospheric reanalysis,  Antarctic Oscillation,  Arctic Oscillation,  applicability