梅垚,胡志群,黄兴友. 2018. 高原对流云的偏振雷达观测研究[J]. 气象学报, (0):-, doi:10.11676/qxxb2018.037
高原对流云的偏振雷达观测研究
The kinematic and microphysical characteristics of the convection cloud in Tibet Plateau region based on dual polarimetric radar observations
投稿时间:2017-10-26  修订日期:2018-03-23
DOI:10.11676/qxxb2018.037
中文关键词:  青藏高原地区;双偏振雷达  对流云  双多反演  相态识别
英文关键词:Tibet Plateau region  dual Doppler radar  convective cloud  wind field retrieval  class classification
基金项目:国家自然科学基金项目(41375038);财政部公益性行业(气象)科研专项“第三次青藏高原科学试验—边界层与对流层观测(GYHY201406001)
作者单位E-mail
梅垚 南京信息工程大学 气象灾害预报预警与评估协同创新中心 154023830@qq.com 
胡志群 中国气象科学研究院 灾害天气国家重点实验室 E-mail:huzq121@163.com 
黄兴友 南京信息工程大学 气象灾害预报预警与评估协同创新中心 hxyradar@126.com 
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中文摘要:
      利用可移式C波段双偏振雷达(C-POL),以及那曲新一代天气雷达(CINRAD\CD)于2014年7月30日和8月5日在西藏那曲地区的观测资料,并通过双多普勒雷达风场反演、偏振雷达相态识别,清晰展示了这两次高原冰雹云发生发展的动力、微物理、热力结构特征。结果表明:高原地区的对流多在午后出现,水平及垂直尺度不大,但是对流频繁、生消快,一般持续几十分钟左右。从RHI扫描的Z_H、Z_DR,以及反演的相态(Class)分布图上,可以明显看出,粒子跟随“零线”抬高,不断增长,回波强度也越来越大,并最终超过主上升气流从另一侧降落,形成冰雹墙的整个动力与微物理过程。从连续时次的RHI扫描图上,还观测到一次对流单体发生发展过程中相态从湿雪到冰雹的变化,单体刚刚触发时,回波高度不高,强度还很弱,但是却出现成片的湿雪区域,说明上升气流非常旺盛,将本来落到0℃以下的未完全融化的湿雪重新带到0℃层以上,通过凝华、淞附、攀附等物理过程,仅仅10多分钟,这些湿雪就能够迅速增长成为冰雹。这些湿雪重新凝结过程中,潜热释放,进一步促进了不稳定结构,加强了上升气流和下沉气流。因此,如果某个刚刚生成的弱回波区域内,在融化层以上出现大量的湿雪,往往预示着该区域上升气流强劲,会迅速发展成强回波单体
英文摘要:
      Based on the data on July 30 and August 5, 2014 in Naqu, Tibet, detected with the mobile C-band dual polarimetric radar (C-POL) and Chinese new generation weather radar in Naqu (CINRAD\CD), two cases of hailstorm cell and its dynamical, microphysical and thermal characteristics are detailedly demonstrated by means of two Doppler radars wind field retrieval and dual polarization radar hydrometeor class identification technique. The convective cells mostly appear in the afternoon in the plateau region. Although the horizontal and vertical scales of cells are small, they are frequent occurrence and rapid evolution, which generally last for dozens of minutes. In the RHI (range height indicator) images of ZH, ZDR and Class, the whole dynamic and microphysical process can be obviously seen in where the hydrometeor particles raise and grow up following the “zero line” and accompanying the echo intensity increase, then form a hail wall dropping down in the other side of main updraft after overtaking it. From the successive three RHI scan, the class of particles change from wet snow to hailstorm during the evolution process in one convective cell. The height of the echo is lower and its intensity is very weak when the cell is just triggered. However, when a large amount of wet snows appear above the melting level, it always hints that the updraft is so strong that the wet snows are brought back to high levels while they have not completely melted in the air below the melting level. Through physical processes such as condensation, rime, and attachment, the wet snow can rapidly grow into hailstones in just over 10 minutes. During the recondensation of wet snows, the unstable structures are promoted and the updraft and downdraft are strengthened further because of latent heat releasing. Therefore, if numerous wet snows appear in a newly generated weak echo region above the melting level, it usually indicates that the region occurs strong updraft and will develop rapidly to a strong cell.
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