Statistical Characteristics of the Northeast China Cold Vortex and Its Impact on Precipitation Distribution from 2000 to 2019

The Northeast China Cold Vortex (NCCV) is a circulation system that significantly affects the weather and climate in northeastern China (NEC). Based on previous studies, a method for identifying and tracking NCCVs is constructed in this study. National Centers for Atmospheric Prediction/National Center for Atmospheric Research reanalysis data from 2000 to 2019 are used to objectively identify and track NCCVs. The temporal and spatial distribution characteristics, duration, intensity, and size of NCCVs are analyzed on this basis, and the relationship between NCCVs and precipitation in NEC during the warm season (May–September) is discussed using the hourly precipitation observation data from 216 national automatic weather stations. NCCVs in NEC have no discernible long-time trend, but there is significant interannual variability and a distinct seasonal variation, which is more likely to occur during the warm season. The duration of NCCVs is generally 48–72 hours, and the size range is mainly distributed in 600–1200 km. The mean size and intensity of NCCVs are both larger in the cold season than in the warm season. The high occurrence of NCCVs presents an east–west zonal distribution along the latitude of 45°–55°N. NCCVs contribute more than 20% of the precipitation in the warm season in NEC. Spatial distribution of precipitation proportion varies in four classes: 0.1–5 mm h⁻¹, 5–10 mm h⁻¹, 10–20 mm h⁻¹, and ≥20 mm h⁻¹, and the local characteristic of heavy precipitation is remarkable. The maximum contribution of NCCVs to rainstorms can exceed 70%.