摘要
如何利用现有雷达体扫数据重构反射率或其它物理量的时间—高度剖面,提高雷达体扫垂直分辨率并使其适用于云微物理结构的分析,是近几年来雷达气象学的重点研究内容之一。本文基于分辨率更高的X波段双偏振雷达体扫数据,对目前最新的柱垂直廓线(Columnar Vertical Profile,简称CVP)重构算法从目标区范围的选取方面进行改进,使其能够应用于水平尺度较小的局地降水云以及发展演变迅速的对流云。结果显示:对于高原地区局地降水云个例,目标区选取5 km(径向范围)×10°(方位角范围)组成的较小扇形区域,与云雷达的对比显示,改进的CVP方法重构的基本反射率(ZH)垂直廓线体现了回波的垂直结构,尤其是中高层对流泡的结构特点,相应的时间—高度序列能够较好地反映回波顶高的变化以及中高层强度逐渐减弱、低层强度逐渐增加的特点;对于华北地区发展旺盛且局地水平不均匀的对流云个例,本文改进了原始的CVP重构目标区选取方法,对高、低仰角层采用变化的径向范围并调整插值参数,改进后重构的ZH垂直廓线有效避免了低层回波水平分布相对不均匀导致的重构分层结构,显示出高、低层回波特征以及不同阶段目标区云结构的转变。进一步对比改进前后CVP方法重构建立的各偏振量时间—高度序列,改进后准确显示了个例云系微物理特征及其随时间的变化,揭示了高原地区局地降水云中对流泡的形成及其播撒作用机制,华北地区对流云成熟阶段的各偏振量垂直分布特征及其演变。
In recent years,the reconstruction of the time–height profile of radar reflectivity and other parameters using volume coverage pattern data to improve its vertical resolution and make it suitable for cloud microphysical research has been one of the popular topics in radar meteorology.Based on the volume scan data of X-band dual-polarization radar with high resolution,this paper improves the CVP(Column Vertical Profile)algorithm by varying the target area selection for applying it to rapidly developing convective clouds and locally generating clouds with small horizontal scales.The comparison with cloud radar indicates that for the local precipitation in the plateau area,the basic reflectivity(ZH)vertical profile reconstructed using modified CVP with a small area comprising 5 km(radial range)×10°(azimuth coverage)can reasonably reflect the characteristics of generating cells in the high level of clouds.Gradual decreasing of ZH from high layer,and gradual increasing of ZH toward low layer are indicated by the corresponding ZH time-height series.For the vigorously developed convective cloud in North China,the area selection strategy of the original CVP was enhanced by adopting variations in the selected radial range for high and low-elevation layers.The new vertical profile of ZH considerably avoids the“zig-zag”structure caused by the uneven horizontal distribution of the low-level echo while retaining the primary characteristics of the high-level echoes of convective cloud in the vigorously developing stage and the transformation of cloud structure at different stages.Moreover,by comparing the reconstructed results of modified CVP with the original CVP,a new time-height series is obtained for different polarization parameters,which shows the changing cloud microphysical characteristics over time,thereby revealing convection-generated cells mechanisms of formation and its seeding effect on the plateau.In the mature stage of convective cloud in North China,vertical distribution characteristics of polarization
作者
贾烁
杨洁帆
雷恒池
韩辉邦
周万福
闫非
JIA Shuo;YANG Jiefan;LEI Hengchi;HAN Huibang;ZHOU Wanfu;and YAN Fei(Key Laboratory of Cloud-Precipitation Physics and Severe Storms(LACS),Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;University of Chinese Academy of Sciences,Beijing 100049;Office of Weather Modification in Qinghai Province,Xining 810000;Hebei Provincial Weather Modification Center,Shijiazhuang 050021)
出处
《大气科学》
CSCD
北大核心
2024年第3期938-954,共17页
Chinese Journal of Atmospheric Sciences
基金
西北区域人工影响天气能力建设项目ZQC-R18209
河北省“十三五”气象重点工程--云水资源开发利用工程示范项目“黑龙港流域对流云人工增雨作业技术示范”
国家自然科学基金项目41875172、42075192。
关键词
体扫数据
CVP
方法改进
目标区
插值参数
时间—高度序列
结构特征
微物理特征
VCP(Volume Coverage Pattern)data
Improvement of CVP(Columnar Vertical Profile)algorithm
Target area
Interpolation parameters
Time–height series
Character of structure
Microphysical characteristics
