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气象:2016,42(6):686-695
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局部大暴雨形成的机理与中尺度分析
(1.中国气象局河南省农业气象保障与应用技术重点开放实验室,郑州 450003 河南省开封市气象局,开封 475004;2.中国气象局河南省农业气象保障与应用技术重点开放实验室,郑州 450003;3.河南省气象台,郑州 450003;4.河南省开封市气象局,开封 475004)
The Forming Mechanism and Mesoscale Analysis of Local Heavy Rainfall
(1.Henan Key Laboratory of Agrometeorological Ensuring and Applied Technique of CMA, Zhengzhou 450003 Kaifeng Meteorological Office of Henan Province, Kaifeng 475004;2.Henan Key Laboratory of Agrometeorological Ensuring and Applied Technique of CMA, Zhengzhou 450003;3.Henan Meteorological Observatory, Zhengzhou 450003;4.Kaifeng Meteorological Office of Henan Province, Kaifeng 475004)
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投稿时间:2015-02-10    修订日期:2016-01-26
中文摘要: 利用常规气象观测资料、区域自动站加密观测资料、NCEP逐6 h的1°×1°的再分析资料和FY 2C卫星逐时TBB资料、多普勒雷达探测资料,对2012 年7月7—8日河南商丘地区大暴雨天气过程形成机理和中尺度系统活动特征进行了研究,结果表明:500 hPa低槽与低层东西向切变线和低空急流相互配合、共同作用是此次大暴雨形成的大尺度环境条件。中尺度分析显示:多个中尺度雨团的活动形成了4个大暴雨中心,中尺度雨团与MαCS相伴,而MαCS是由多个MγCS和MβCS合并、加强的结果。这些MγCS和MβCS是由地面中尺度辐合线或辐合中心触发产生并发展,MαCS覆盖区下强降水回波的移动和发展与地面中度辐合系统对应较好,大暴雨出现在地面辐合系统形成后的1~2 h内;而暖平流导致的局地升温,是地面中尺度辐合系统形成的主要原因。TBB梯度与降水强度成正比,当TBB/0.5°E≥34℃,并且TBB≤-63℃时,将产生30 mm·h-1的强降水;当MCS发展成熟时强降水发生在中尺度对流云团TBB低值中心附近,当TBB在1 h内降低31℃以上时,1~2 h后该地将出现雨强为50 mm的短时强降水。因此,地面热力不均匀导致的局地升温是此次地面中尺度辐合系统生成的主要原因,而地面中尺度辐合系统的发生发展触发了中小尺度对流系统的发生发展,导致了局部大暴雨的产生。根据中小尺度对流云团的TBB强度及变幅,可提前1~2 h预报短时强降水。
Abstract:By using regular meteorological observations data, regional automatic station observation data, Doppler radar data, 1°×1° NCEP 6 h interval reanalysis data and hourly FY 2C satellite TBB data, the forming mechanism and mesoscale system activity feature of the heavy rainstorm seen in Shangqiu in 7-8 July 2012 are analyzed. The results show that the trough at 500 hPa and east west shear line in the low level are compatible with the low level jet stream, forming the large scale circulation for the rainstorm. Mesoscale analysis shows that several convective cells develop into four rainfall centers, and the convective cells accompany the MαCS, which is merged and strengthened by some MγCS and MβCS. The MγCS and MβCS are triggered, generated and developed by the ground mesoscale convergent systems or convergence center. The movement and development of heavy precipitation echoes correspond better with ground moderate convergence systems. The rainstorm occurs after the formation of ground convergence system within 1-2 hours. The warming in some local areas caused by warm advection is the main cause for the formation of surface mesoscale convergence system. Rainfall intensity is proportional to the TBB gradient. When TBB/0.5°E≥34℃, and TBB≤-63℃, severe rainfall of 30 mm·h-1 would occur. When MCS (mesoscale convective system) gets matured, heavy precipitation occurs near the low TBB center of the mesoscale convective clouds and when TBB is lower than 31℃ in one hour, short time severe rainstorm of 50 mm intensity would appear in 1-2 hours. Therefore, the uneven local ground heat warming is the main cause of this moderate convergence system. Moreover, the development of ground moderate convergence systems trigger the evolution of mesoscale convective systems, leading to the generation of local heavy rainstorm. So according to the TBB intensity and the variation of mesoscale convective clouds, forecast of short time heavy rainfall can be made in advance of 1-2 hours.
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基金项目:公益性行业(气象)科研专项(GYHY201306012)资助
引用文本:
喻谦花,郑士林,吴蓁,吕哲源,2016.局部大暴雨形成的机理与中尺度分析[J].气象,42(6):686-695.
YU Qianhua,ZHENG Shilin,WU Zhen,LU Zheyuan,2016.The Forming Mechanism and Mesoscale Analysis of Local Heavy Rainfall[J].Meteor Mon,42(6):686-695.