冷涡背景下哈尔滨地区暖季短时强降水特征

Characteristics of Short-term Heavy Precipitation in the Warm Season in Harbin Area under the Background of Cold Vortex

摘要:

利用2018-2022年5-9月逐小时降水数据和ERA5再分析资料，研究在冷涡背景下哈尔滨地区暖季短时强降水特征。统计并通过分析个例得出以下结论：（1）短时强降水西北部和中部较东部明显多。（2）较弱、中等强度短时强降水出现频次7月最多，5-8月逐月增加，极端短时强降水8月最多。（3）产生短时强降水的冷涡处于发展期的占61％，成熟期占14％，减弱期占24％；其中短时强降水站次在发展期最多，成熟期少于发展期，减弱期最少。（4）发展期以中等强度和较强短时强降水为主，成熟期以较弱和中等强度短时强降水为主，减弱期以中等强度和极端短时强降水为主,暴雨分散且局地。（5）发展期上升运动与强降水落区有很好的对应关系，高低层急流耦合作用强，减弱期上升运动弱于发展期，成熟期最弱。（6）发展期水汽条件最好，整层比湿较大且稳定维持，减弱期比湿次之，成熟期最小。

Abstract:

Hour-by-hour precipitation data and ERA5 reanalysis data from May to September 2018-2022 are used to study the characteristics of short-term heavy precipitation in the warm season in Harbin area under the background of cold vortex. Statistics and the following conclusions are drawn from the analysis of individual cases: (1) There is significantly more short-duration heavy precipitation in the northwestern and central parts of the region than in the eastern part. (2) The frequency of weak and medium-intensity heavy precipitation occurs most frequently in July, and increases month by month from May to August, with extreme heavy precipitation occurring most frequently in August. (3) The cold vortex that produces short-term heavy precipitation accounts for 61% in the development period, 14% in the maturity period, and 24% in the weakening period; among them, the number of stations with short-term heavy precipitation is the most in the development period, the maturity period is less than the development period, and the weakening period is the least. (4) The development period is dominated by moderate intensity and stronger short-term heavy precipitation, the maturity period is dominated by weaker and moderate intensity short-term heavy precipitation, and the weakening period is dominated by moderate intensity and extreme short-term heavy precipitation, with heavy rainfall scattered and localized. (5) There is a good correspondence between the upward movement and the area of heavy precipitation in the developmental period, with strong coupling of high and low level rapids; the upward movement in the weakening period is weaker than that in the developmental period, and the weakest in the maturation period. (6) The best water vapor conditions are found in the developmental period, the whole layer specific humidity is larger and stably maintained, and the specific humidity in the weakening period is the second largest and the smallest in the maturation period.