摘要:由层状云和镶嵌在层状云中的对流单体组成的积层混合云系是一种重要的降水系统，为研究云粒子破碎对积层混合云系中对流较强区域和层云区域中的云微物理参量测量影响的差异，本文提出了一个时变阈值的破碎粒子识别方法，并利用该方法研究了破碎云粒子在层云区域与对流区域对云微物理参量测量影响的异同。经研究发现破碎粒子对粒子谱影响在小粒径端（500 μm以下）和大粒径（1000 μm以上）两端都存在，其中在层云区，破碎粒子在小粒径端的主要影响位于300 μm以下，而在对流云区，主要影响的小粒径段位于500 μm以下。就整体平均而言，破碎粒子对对流云区粒子谱的影响要比对层云区的影响高出20%以上。在粒子数浓度测量上，破碎粒子对整个层云区粒子数浓度影响的平均值是4.56倍，对整个对流云区粒子数浓度影响的平均值是8.47。与层云区相比，破碎云粒子对对流云区的粒子数浓度影响更大，其影响程度就平均而言接近2倍的关系。在冰水含量测量上，破碎粒子对整个层云区冰水含量测量影响的平均值是1.34倍，对整个对流云区冰水含量测量影响的平均值是1.74倍。与层云区相比，破碎云粒子对对流云区的冰水含量测量影响大约增加了30%。
关键词:层状云/
嵌入式对流/
破碎粒子/
云微物理
Abstract:The stratiform clouds with embedded convective cells is an important precipitation system. Precise knowledge on the microphysical structure of the clouds can be very useful for the development of the weather numerical prediction model and the cloud water resource. In our study, a time-variant threshold method to identify the shattered fragments is proposed to study the different influence of the shattered particles on the microphysical measurement in the stratiform cloud region and the convection cloud region. Then the shattered impact on the particle spectrum distribution (PSD), particle number concentration, and ice water content measurement is analyzed. It is found that the influence of the shattered artifacts on the PSD can be in the two ends (<500 μm and >1000 μm). In the stratiform area the influence on the small end is less than 300 μm, while in the convective area it is less than 500 μm. On average, the shattered particles have 20% higher impact on the PSD in the convective region than that in the stratiform region. The shattered fragments can increase the particle number concentration by 4.56 times in the stratiform area while in the convective area the value is 8.47 times, which is nearly twice that of the stratiform area. The shattered artifacts can also overestimate the ice water content in the convective region more than 30% than that in the stratus.
Key words:Stratiform clouds/
Embedded convection/
Shattered particle/
Cloud microphysics
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