The main characteristics of the atmospheric circulation in the autumn(from September to November)of 2023 are as follows.The polar vortex is characterized by a single-pole type in the Northern Hemisphere and the circulations present a 5-wave mode in middle and high latitudes.In Eurasia,the circulation pattern of the westerly wind belt is flat without significant ridge and trough.In the offshore areas of China,there are 16 gale events above Beaufort scale 8,including three by tropical cyclones,three jointly by tropical cyclones and cold air,three by cold air and extratropical cyclones,and 7 by cold air.There are 4 tropical cyclones generated over western North Pacific and the South China Sea,while 22 tropical cyclones are named in other oceans.Tropical cyclone activities are less than the climate normal.There are 17 sea wave events with wave height greater than 2.0 m,with large wave days accounting for about 71％of the total number of days in this autumn.The sea surface temperature of offshore areas of China is higher than the climate normal.
维普
万方数据