朱士超, 郭学良. 2014: 华北积层混合云中冰晶形状、分布与增长过程的飞机探测研究. 气象学报, (2): 366-389. DOI: 10.11676/qxxb2014.013
引用本文: 朱士超, 郭学良. 2014: 华北积层混合云中冰晶形状、分布与增长过程的飞机探测研究. 气象学报, (2): 366-389. DOI: 10.11676/qxxb2014.013
ZHU Shichao, GUO Xueliang. 2014: Ice crystal habits, distribution and growth process in stratiform clouds with embedded convection in North China:Aircraft measurements. Acta Meteorologica Sinica, (2): 366-389. DOI: 10.11676/qxxb2014.013
Citation: ZHU Shichao, GUO Xueliang. 2014: Ice crystal habits, distribution and growth process in stratiform clouds with embedded convection in North China:Aircraft measurements. Acta Meteorologica Sinica, (2): 366-389. DOI: 10.11676/qxxb2014.013

华北积层混合云中冰晶形状、分布与增长过程的飞机探测研究

Ice crystal habits, distribution and growth process in stratiform clouds with embedded convection in North China:Aircraft measurements

  • 摘要: 利用中国国家科技支撑计划重点项目环北京地区3架飞机联合云探测试验数据,分析了2009年4月18日和5月1日两次积层混合云中冰晶形状、分布与增长过程。结果表明:飞机在0—-16℃范围的云层内观测到的冰晶形状主要包括板状、针柱状、柱帽状、辐枝状和不规则状。云中低层的冰晶形状受云顶温度影响,云顶温度不同,冰晶形状不同,当云顶温度高于-8℃时,云中低层的冰晶以板状和针柱状为主;当云顶温度低于-13℃时,在云中低层可观测到辐枝状冰晶;当云顶温度低于-18℃时,在云中低层可观测到柱帽状冰晶。同时冰晶形态还受其所处云中位置的影响,在积层混合云中的嵌入对流区含有更多的凇附状冰晶;在融化层以上,冰晶的增长过程主要包括凝华、凇附和聚合过程,在垂直方向上,随着高度降低云中过冷水增多,冰晶的凇附增长也相应增强。积层混合云中的对流区和层云区粒子谱下落拓宽速率有明显差别,在4.8—4.2 km(-11.6—-8℃)高度层,对流区粒子谱拓宽速率为3 mm/km,而层云区为3.67 mm/km,层云中粒子拓宽增长的速率略高于对流区;而在4.2—3.6 km(-8—-5℃)高度层,对流区的粒子谱拓宽速率为6.67 mm/km,层云区为2.33 mm/km,对流区的粒子拓宽增长速率是层云区的近3倍,主要原因是对流区低层的过冷水含量较高。

     

    Abstract: Ice crystal habits, distribution and growth process in the two cases of stratiform clouds with embedded convection on 18 April 2009 and 1 May 2009 are analyzed with the data observed during the Beijing Cloud Experiment (BCE). The results show that ice crystal habits in clouds with temperature between 0—-16℃ were predominantly of plate, needle-column, capped-column and dendrite type, as well as irregular. Ice crystal habits were affected by the cloud top temperature (CTT) and were different with the change of CTT. Plate and needle-columns were predominant habits as CTT warmer than -8℃, but dendritic and capped-column crystals were observed just as CTT colder than-13℃ and -18℃, respectively. At the same time, ice crystal habits were also affected by their locations in cloud, and there were a lot of heavy rimed crystals in embedded convective regions. Above the melting layer, ice particle grew mainly by the deposition, riming and aggregation process, and the riming process became more intense in a lower cloud layer due to the increase of supercooled liquid water content. The broadening rate of Particle Size Distributions (PSDs) is obviously different between embedded convections and stratiform clouds in the vertical direction. For example, at levels 4.8—4.2 km (-11.6—-8℃), the PSDs broadening rate in embedded convections is 3 mm/km, and smaller than 3.67 mm/km in stratiform clouds, but at levels 4.2—3.6 km (-8—-5℃), the PSDs broadening rate in embedded convections is 6.67 mm/km, which was almost three times as big as 2.33 mm/km in stratiform clouds. This is mainly due to that embedded convections had more supercooled liquid water than stratiform clouds at levels 4.2—3.6 km.

     

/

返回文章
返回