Temporal and Spatial Distributions of Precipitation Related to the Northeast Cold Vortex in the Warm Season in Jilin Province during 1981–2019

Based on quality control of the hourly rain gauge dataset in 39 years (1981–2019) from 51 meteorological stations provided by the Meteorological Information Center of Jilin Province, the spatial and temporal distribution characteristics of precipitation during the northeast cold vortex process in the warm season were analyzed. Results showed that: (1) Overall, precipitation in Jilin Province exhibited a clear diurnal variation. The peaks of diurnal precipitation and frequency occurred during 1600–1800 BJT (Beijing time). Frequency of 0.1–5 mm h⁻¹ precipitation (P＜5 mm h⁻¹) exhibited a large value in the mountainous area in eastern Jilin Province. However, the high-value center moved to the south–central part of Jilin Province, whereas the precipitation was larger than 5 mm h⁻¹ (P＞5 mm h⁻¹). (2) Only a slight difference in the spatial distribution of the contribution of P＜5 mm h⁻¹ to warm-season precipitation in Jilin Province during the daytime was observed. However, the value center was detected more clearly in the mountainous area in eastern Jilin Province at night. The contribution of the gauge record between 5 mm h⁻¹ and 10 mm h⁻¹ (5 mm h⁻¹＜P＜10 mm h⁻¹) was greater in central Jilin Province. Moreover, the contribution was greater during the daytime than at night. By contrast, for P＞10 mm h⁻¹, the high-value center moved to the mid-west of Jilin Province. Similarly, the contribution was greater during the daytime than at night. (3) The rainfall amount of P＜5 mm h⁻¹ accounted for 61% of total precipitation, and the rainfall amounts of 5 mm h⁻¹＜P＜10 mm h⁻¹ and P＞10 mm h⁻¹ accounted for about 20% of total precipitation. The contribution of P＜5 mm h⁻¹ exhibited a decreasing trend in recent years. By contrast, the contribution of P＞10 mm h⁻¹ exhibited an increasing trend.