Abstract:Based on ERA5 hourly reanalysis data of atmospheric circulation field with horizontal resolution of 0.25°×0.25°, geopotential height data and temperature, the northeast cold vortex process and its climate change characteristics from 1979 to 2023 are analyzed. The results reveal that there are more northeast cold vortexes in the early 1990s and mid-2000s, and relatively fewer in the 2010s. The frequency of northeast cold vortex shows higher in the warm season than in the cold season, with the highest in June and the lowest in March. Its average duration is 4 days, with the shortest duration in April and the longest duration in January. The northeast cold vortex is mostly generated in the range of 45°-60°N, 100°-120°E and dies out within 40°-55°N near 140°E. The center of the northeast cold vortex is mainly concentrated within 45°-55°N and 115°-135°E. The northeast cold vortex mainly moves towards the east and southeast. To the east of 120°E, the average intensity of the cold vortex is stronger and weaker to the west. The intensity distribution of the northeast cold vortex within the year is stronger in the cold season than in the warm season. The intensity difference between the grids in the analysis area is the largest in March, and the smallest in June. The annual average intensity and circulation of northeast cold vortex show a significant weakening trend from 1979 to 2023. There is a significant negative correlation between the intensity of the northeast cold vortex and the temperature in most months in Northeast China, but a significant positive correlation with precipitation in April and June.