摘要
利用常规资料、卫星及fnl再分析资料,对2017年发生在青海省三次大到暴雨天气过程进行研究。得出结论:(1)位涡中低层为负值,高层为正值,有利于低层气旋性涡度的增加,易储存和释放不稳定能量,造成强烈的上升运动,更利于暴雨发生;(2)低层中MPV1的大绝对值中心、等值线密集区与强降水对应较好,等值线密集区呈西南—东北向分布;(3)中低层中35°N的辐合中心与MPV2零线对应,呈正负分布,强降水区为负值;(4)MPV1的绝对值大中心及密集区与强降水发区的高温高湿区、强上升区、正涡度的大值中心及假相当位温梯度带相对应,降水发生前MPV2为0,强降水发生时增幅为0.2PVU;(5)冷空气越强,水汽图像中干侵入与高层的高位涡对应越好,为研究夏季弱冷空气与高空短波槽扰动在暴雨中的触发作用提供新的思路。
A synoptic analysis of three heavy rain events with conventional data,meteorology satellite data and reanalysis data in 2017.The results showed that the negative area at low layer and the positive area at high layer,it was beneficial to enhancing cyclonic vorticity,accumulation and releasing unstable energy,causing the strong updraft airflow,it was more conducive to happening heavy rain.The region of heavy rain located in center of large absolute value and the dense isoline region of MPV1,the dense isoline region was distributed from southwest to northeast.The region of the positive vorticity center near 35°N at the middle and lower layers corresponding with zero curve of MPV2,heavy rain located in the negative value of MPV2.The center of large absolute value and dense area of MPV1 corresponding to heavy rainfall area of warm and moist area,the strong ascent motion area,center of positive vorticity and pseudo-equivalent potential temperature gradient area.The value of MPV2 is zero before rain happening,it increased 0.2 PVU when rain happening.Dry intrusion in water vapor image corresponding to high value of potential vorticity at higher layer when cold air getting stronger.It provided new thinking of researching triggering action between weak cold air and short-wave trough at high altitude with heavy rain in su mmer.
作者
祁彩虹
朱永丰
张宁瑾
胡垚
QI Cai-hong(Qinghai Meteorological Observatory,Xining,Qinghai 810001)
出处
《农业灾害研究》
2021年第1期85-87,89,共4页
Journal of Agricultural Catastrophology
关键词
大到暴雨
位涡
湿位涡
斜压项
特征分析
Heavy rain
Potential vorticity
Moist potential vorticity
Atmospheric baroclinicity
Characteristics analysis
