Abstract:The main characteristics of the atmospheric circulation in autumn (from September to November) 2019 are as follows. The polar vortex is characterized by a circumpolar type in the Northern Hemisphere and the atmospheric circulation presents a four-wave mode in middle and high latitudes. As time goes by, the meridional gradient of the Eurasian mid-high latitude circulation is increasing, and the cold air is strengthening, but it is still weaker than the historical average. The western Pacific subtropical high is stronger than the historical average and tropical cyclones are frequent. There were 17 gale processes stronger than 8 grade over offshore areas of China, including 9 produced by cold air, 4 by tropical cyclones, three by cold air and tropical cyclones, and one by cold air and extratropical cyclones. In western North Pacific and the South China Sea, there were 16 tropical cyclones. In addition, there were 27 tropical cyclones in the world's other oceans. There were 9 rough sea wave processes above two m. In autumn 2019, the sea surface temperature has an overall trend of decrease, while the decrease rate in northern seas is larger than that in southern seas.