李思聪^1,2,,
李昀英^1,,,
孙国荣^1,3,
宋文婷¹
1. 国防科技大学气象海洋学院, 南京 211101
2. 中国人民解放军95364部队, 广东湛江 524300
3. 中国人民解放军92859部队, 天津 300000

基金项目: 国家重点研发计划"重大自然灾害监测预警与防范"重点专项（2018YFC1507604）资助


详细信息

作者简介: 李思聪, 男, 1993年生, 硕士, 主要从事云降水物理学研究.E-mail:atmos_lsc@outlook.com

通讯作者: 李昀英, 女, 教授, 主要从事云动力学和云气候学研究.E-mail:ghlyy@mail.iap.ac.cn

中图分类号: P401

收稿日期:2018-10-16
修回日期:2019-03-30
上线日期:2019-12-05

Cloud microphysical characteristics in the development of stratocumulus clouds over Eastern China

LI SiCong^1,2,,
LI YunYing^1,,,
SUN GuoRong^1,3,
SONG WenTing¹
1. College of Meteorology and Oceanography, National University of Defense Technology, Nanjing 211101, China
2. Unit No. 95364 of Chinese People's Liberation Army, Guangdong Zhanjiang 524300, China
3. Unit No. 92859 of Chinese People's Liberation Army, Tianjin 300000, China


More Information

Corresponding author: LI YunYing,E-mail:ghlyy@mail.iap.ac.cn

MSC: P401

--> Received Date: 16 October 2018
Revised Date: 30 March 2019
Available Online: 05 December 2019


摘要
摘要:基于2007—2010年的CloudSat卫星观测数据，以云层液态水路径为指标将层积云的发展过程划分为五个阶段，对比研究了中国东部降水与非降水层积云发展过程中云微物理特征和云微物理机制的演变，并分析了其海陆差异.研究表明：非降水层积云中，云滴增长主要通过凝结过程完成，但云滴的凝结增长有限，难以形成降水，在非降水层积云发展的旺盛阶段，云层中上部云滴发生较弱的碰并过程.降水层积云中云滴碰并增长活跃，当云层液态水路径小于500 g·m^-2时，云滴在从云顶下落至云底的过程中持续碰并，并在云底附近出现云水向雨水的转化；当降水层积云液态水路径超过500 g·m^-2时，云滴碰并增长主要发生在云层上部，在云层中部，云液态水含量、液态粒子数浓度和液态粒子有效半径达到最大，云水向雨水的转化最为活跃.层积云微物理特征的海陆差异主要是由海陆上空气溶胶浓度和云中上升气流强度不同导致的.在非降水层积云中下部，陆地丰富的气溶胶为云滴凝结增长提供了充足的云凝结核，因而云微物理量的量值在陆地上空更大，而在云层中上部，云滴凝结增长达到极限，海洋充足的水汽输送使云微物理量的量值在海洋上空更大.当降水层积云液态水路径大于500 g·m^-2时，陆地层积云中更强的上升气流使大量云滴在云层中上部累积滞留，云滴碰并增长活跃，云层中上部云微物理量的量值在陆地上空更大.
关键词: 层积云/
降水/
云微物理特征

Abstract:Based on the finely resolved CloudSat data products from 2007 to 2010, the microphysical characteristics of precipitating and non-precipitating stratocumulus clouds over Eastern China are investigated in this study, cloud microphysical mechanism evolution during the development of stratocumulus clouds which are divided into five groups based on the magnitude of liquid water path are studied, and the sea-land difference in cloud microphysical properties are also examined. The quantity value of liquid water path in the precipitating stratocumulus clouds is greater than that in the non-precipitating stratocumulus clouds. In non-precipitating stratocumulus clouds, the condensation process is the primary mechanism for hydrometeor particle growth, but this mechanism is inversely proportional to the particle radius, therefore, it is difficult for cloud droplets to form drizzle or raindrops simply through condensational growth. In the vigorous developmental stage of non-precipitating stratocumulus clouds, the relatively feebler coalescence process appeared in the upper layers of clouds. The coalescence process becomes evident in precipitating stratocumulus clouds. When the cloud liquid water path is less than 500 g·m^-2, cloud droplets grow in size continuously by the coalescence process as they fall through the entire cloud layer, and the raindrops appear near the cloud base. When the cloud liquid water path becomes larger than 500 g·m^-2, the coalescence process occurs mostly in the upper layers. In the middle part of the cloud, the transition from cloud droplets to raindrops is most active, and the maximum values of cloud liquid water content, liquid number concentration and liquid effective radius appear in this level. The difference in cloud microphysical properties between sea and land can be accounted for the difference in updraft strength and aerosol concentration, aerosols produced by anthropogenic activity over land areas can act as the cloud condensation nuclei and promote the cloud droplets condensation process, thus the values of cloud microphysical properties over the land are greater than that over the sea. While in the upper layers of clouds, cloud droplets condensational growth is limited, sufficient moisture over the sea becomes more crucial in the development of non-precipitating stratocumulus clouds. As for precipitating stratocumulus clouds with liquid water path greater than 500 g·m^-2, the stronger updrafts in clouds over land can prolong the lifetime of smaller particles and promote particle growth in vicinity of cloud top, meanwhile, the values of cloud microphysical properties are greater over the land.
Key words:Stratocumulus clouds/
Precipitating/
Cloud microphysical characteristic



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