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投稿时间:2022-05-14 修订日期:2023-06-28
投稿时间:2022-05-14 修订日期:2023-06-28
中文摘要: 结合毫米波云雷达数据和飞机观测数据,分析研究了2019年11月29—30日降雪云系的宏微观特征。此次降雪从29日14时持续至30日01时,受水汽输送影响,降雪量呈现增多—减少—再增多的趋势。云系的厚度变化明显,毫米波云雷达最大回波为25 dBz,地面小时降雪量大于1 mm的时刻与云雷达强回波(10~15 dBz)和大值谱宽带出现的时间有较好的对应关系。云内冰晶转化和上升气流存在的高度在4 km以上,云雷达正的径向速度主要在降雪的前中期。飞机观测发现云内以冰晶为主,存在霰粒子和聚合体。冰晶在下落过程中,通过碰并、碰连和凇附等微物理过程增长,同时云雷达的径向速度和谱宽有所增加。飞机探测到大于500 μm的冰晶时,云雷达回波强度大于0 dBz。在4400~4700 m,云雷达速度谱宽急剧变化。研究结果为进一步分析张家口地区冬季降雪云系的宏微观结构和增雪潜力提供了理论参考。
中文关键词: 毫米波云雷达,飞机观测,降雪,云宏微观特征,冰晶
Abstract:A snowfall event occurred in Zhangjiakou in 29-30 November 2019. The snowfall clouds were thoroughly analyzed based on millimeter-wavelength cloud radar observations and aircraft observations to explore the macro- and microphysical characteristics of the clouds. This snowfall event lasted from 14:00 BT 29 to 01:00 BT 30. Restricted by moisture transport and supply, the ground precipitation showed an increasing-decreasing-increasing tendency. The vertical depth of clouds varied distinctly with time. The maximum reflectivity of cloud radar was 25 dBz. The recorded time with ground precipitation more than 1 mm corresponded well to the period that cloud radar detected high values of reflectivity (10-15 dBz) and spectral width. The growing ice crystals and updraft air flows mainly existed above 4000 m. Positive values of radical velocity detected by cloud radar were mostly in mid-to-early stages of snowfall. Ice crystals were the dominated particles within clouds according to the sounding of airborne probes. Besides, graupels and aggregated particles were captured. As ice crystals〖JP2〗 were falling, they grew up through the microphysical processes of coalescence-collision and contact-freezing. Meanwhile the cloud radar observed magnitude of both radical velocity and spectral width were augmented. When ice crystals larger than 500 μm were detected, the reflectivity of cloud radar was greater than 0 dBz. In the heights 4400-4700 m, spectral width of cloud radar dramatically changed. These results could further help understand and analyze the macro-and microphysics of winter snowfall clouds and snowfall enhancement potentials in Zhangjiakou Region.
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基金项目:河北省省级科技计划(20375402D)和河北省气象局科研开发项目(20ky28)共同资助
引用文本:
孙啸申,周学思,樊嵘,王晓青,张晓瑞,王梧熠,薛学武,李政昊,2023.张家口2019年11月29日降雪天气的毫米波雷达和飞机观测分析[J].气象,49(8):958-971.
SUN Xiaoshen,ZHOU Xuesi,FAN Rong,WANG Xiaoqing,ZHANG Xiaorui,WANG Wuyi,XUE Xuewu,LI Zhenghao,2023.Analysis of A Snowfall Event at Zhangjiakou on 29 November 2019 Based on Ka-Band Millimeter-Wavelength Radar and Aircraft Observations[J].Meteor Mon,49(8):958-971.
孙啸申,周学思,樊嵘,王晓青,张晓瑞,王梧熠,薛学武,李政昊,2023.张家口2019年11月29日降雪天气的毫米波雷达和飞机观测分析[J].气象,49(8):958-971.
SUN Xiaoshen,ZHOU Xuesi,FAN Rong,WANG Xiaoqing,ZHANG Xiaorui,WANG Wuyi,XUE Xuewu,LI Zhenghao,2023.Analysis of A Snowfall Event at Zhangjiakou on 29 November 2019 Based on Ka-Band Millimeter-Wavelength Radar and Aircraft Observations[J].Meteor Mon,49(8):958-971.