利用2009年4月18日三架飞机联合探测层积混合云资料,结合MICAPS再分析资料、雷达、卫星及地面台站资料等,在准确区分自然云区与催化响应区的基础上,对这次降水性层积混合云的微结构和催化物理响应进行了深入研究.结果表明:云上部(4 800 m层,距云顶1 700 m,距云底3 000 m)累积了云中大部分的过冷水,是云内发展强盛区;云上部嵌入式积云区温度低于周围层云区2℃,积云区含水量分布不均,最大值为1.5 g/m3,标准差为0.4 g/m3,而层云区含水量最大值和标准差分别为0.6 g/m3和0.15 g/m3,积云区和层云区的云滴谱峰值直径分别为25μm和15 μm,云滴数浓度的量级分别为102 cm-3和101 cm-3.对催化云而言,此次联合探测在4 800 m层捕捉到嵌入式积云区的催化响应,人工播撒AgI会促进该层云的消散过程,催化后1h内云区占比由71％降至13％,云中液态含水量持续减少且趋于均匀分布,催化后10 min与20 min云中含水量的最大值分别为1.0 g/m3和1.5 g/m3,标准差为0.3 g/m3和0.15 g/m3,凇附与聚合增长为主要冰相微物理过程,云滴谱先变窄,后因H-M冰晶凇附繁生而拓宽;在云的中下层则受上层催化影响而产生旺盛云区,10 min内该层云区范围显著扩大,云滴及冰相粒子尺度均增加一倍,同时旺盛云区自上而下扩展.%In this research study,the microphysical responses of stratiform clouds on April 18,2009 were studied by analyzing the observational data of three aircrafts.On the basis of distinguishing between the natural and seeded clouds,the observations from radar,satellite,and ground-based sites,together with MICAPS reanalysis,were used.The results indicated that the upper part of the cloud at approximately 4,800 m (1,700 m under the cloud top,and 3,000 m above the cloud base) was the strongest part,with the majority of the subcooled water accumulated within this section.It was observed that the embedded cumulus section maintained a temperature measuring 2 ℃ lower than that of the stratus cloud at the same altitude.Even though the liquid water concentration in the cumulus section were observed to vary greatly,the maximum value of the liquid water concentration was determined to be 1.5 g/m3,with a standard deviation of 0.4 g/m3.The maximum liquid water concentration,and its standard deviation in the stratus area,were 0.6 and 0.15 g/m3,respectively.The peak diameters of the cloud droplet spectra in the cumulus and stratus sections were determined to be 25 and 15 μm,respectively.Also,differences existed in the cloud drop concentrations,with102 cm-3 in the cumulus section,and 101 cm-3 in the stratus section.In regard to the seeded clouds,the observations revealed a response in the cumulus section at 4,800 m.The artificial AgI which was released in the cloud caused a dissipation in the top portion of the cloud,which resulted in a decrease in the proportion of the cloud's area from 71％ to 13％.The liquid water in the cloud was consumed,and tended to fit an equal distribution.Then,at 10 and 20 minutes after the AgI release,the maximum cloud liquid water concentrations were observed to drop to 1.0 and 1.5 g/m3,respectively,and their corresponding standard deviationswere 0.3 and 0.15 g/m3,respectively.Also,the riming and cohering effects were found to be the major microphysics processes in the ice phase.The cloud droplet spectrum was first narrowed,and then widened,due to the H-M ice crystal proliferation mechanism.It was found that the cloud became vigorous below the top section due to the catalytic process which occurred in that region.Furthermore,within 10 minutes,it was observed that the cloud's range increased significantly from top to bottom,with the cloud droplets and ice crystals enlarging horizontally to double their original size.
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