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| 东北冷涡中尺度云系降水机制研究 II: 数值模拟 | |
| 引用本文： | 齐彦斌,陶玥,冉令坤,洪延超.东北冷涡中尺度云系降水机制研究 II: 数值模拟[J].气候与环境研究,2012,17(6):797-808. |
| 作者姓名： | 齐彦斌 陶玥 冉令坤 洪延超 |
| 作者单位： | 1. 吉林省人工影响天气办公室,长春,130062 2. 中国气象科学研究院人工影响天气中心,北京,100081 3. 中国科学院大气物理研究所云降水物理和强风暴实验室,北京,100029 |
| 基金项目： | 国家自然科学基金项目40875002、41075098, 中国科学院知识创新工程领域前沿项目ZAP08101, 创新重要方向项目KZCX2-YW-Q03-03 |
| 摘 要： | 在利用卫星、雷达和机载PMS(粒子测量系统)等观测资料对2003年7月8日东北冷涡积层混合云系的降水形成机制分析的基础上,将观测分析与数值模拟研究相结合,用中尺度数值模式对积层混合云系做数值模拟,并结合观测资料进一步分析了积层混合云系的微物理结构、粒子形成过程和降水形成机制,获得如下结果:(1)混合云中对流云具有分层的微物理结构.冰晶含水量最大值出现的高度最高,其次由高到低的排序是雪、云水、霰和雨;雨水主要出现在云的暖区;各种粒子中以雨水含水量最高,其次是霰.对流云体生命期较长,微物理结构基本稳定.(2)粒子形成增长过程有差异.冰晶通过凝华过程增长.雪主要来源于冰晶,产生后主要通过撞冻、收集冰晶和凝华过程增长,其中撞冻过冷云水增长对雪质量贡献最大,其产生率极大值高度与过冷云水相当.丰富的过冷云水,给雪的撞冻增长提供了有利条件.在高、中和低层雪的形成有着不同的机制,高层雪收集冰晶长大后,下落到低层又以雪撞冻过冷云水的结淞增长为主要过程.霰主要由雨滴冻结和雪的转化产生,过冷雨滴与冰晶接触冻结成霰;过冷雨滴收集雪,雪随着雨滴的冻结而转化成霰.因此霰的产生与过冷雨滴关系极大.霰主要撞冻云水、收集雪和冰晶增长,其中撞冻是霰的重要增长过程.雨水主要由霰的融化形成,降水主要是由冷云过程产生的.在过冷层,霰撞冻增长占优势.云上部的冰晶和雪对云的中部具有播撒作用,过冷层中存在丰富的过冷水,对冰相粒子的撞冻增长有利.对云水消耗的分析表明,雨滴对云滴的收集、霰和雪对云水的撞冻增长是消耗云水的主要过程.(3)从各种粒子的形成和增长过程可以看出,大部分雨水由霰融化形成,暖云过程贡献要小得多.可见,降水主要是由冷云过程产生的,这与观测分析的结果一致. |
| 关 键 词： | 微物理结构 粒子增长 降水机制 数值模拟 |
| 收稿时间： | 2012/10/25 0:00:00 |
| 修稿时间： | 2012/11/5 0:00:00 |
Precipitation Mechanism of Mesoscale Cloud System in a Cold Vortex over Northeast China. II: Numerical Simulation |
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| QI Yanbin,TAO Yue,RAN Lingkun and HONG Yancao.Precipitation Mechanism of Mesoscale Cloud System in a Cold Vortex over Northeast China. II: Numerical Simulation[J].Climatic and Environmental Research,2012,17(6):797-808. | |
| Authors: | QI Yanbin TAO Yue RAN Lingkun and HONG Yancao |
| Institution: | Jilin Weather Modification Office, Changchun 130062;Weather Modification Center, Chinese Academy of Meteorological Sciences, Beijing 100081;Laboratory of Cloud-Precipitation Physics and Severe Storm, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing 100029;Laboratory of Cloud-Precipitation Physics and Severe Storm, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing 100029 |
| Abstract: | Precipitation resulting from a hybrid of cumulus and stratus in a cold vortex in Northeast China on July 8 2003 was studied. A hybrid cloud simulation using the ARPS (Advanced Regional Prediction System) model was conducted. On the basis of the observation and simulation, the hybrid cloud microphysical structure, hydrometeor formation process, and precipitation mechanism were investigated. The results are as follows: (1) The cumulus in the hybrid cloud featured multi-level microphysical structure. The ice content maximum was located at the highest level among five hydrometeors, followed by, from high to low, snow, cloud water, graupel, and rain water appeared in the warm cloud area. Rain water content is hightest in all hydrometeors, graupel was the second most abundant type of content. With a longer lifetime, the cumulus exhibited essentially stable microphysical structure. (2) The hydrometeors had different microphysical growth processes. The ice mixing ratio increased via sublimation. The snow resulted mainly from ice crystals, growth through accretion, collection of ice, and sublimation. The accretion of supercooled cloud water contributed greatly to snow growth. Both of their production rates reached maxima at the same height. The rich supercooled cloud water was favorable to the accretion growth of snow. The high-, medium-, and low-level snows had different formation mechanisms. The upper-level snow grew by collecting ice crystals. Then, snow fell to the low level and grew through accretion of supercooled cloud water. Graupel was produced by raindrop freezing and auto conversion of snow. Thus, graupel production was associated with supercooled raindrops. The source of the graupel was cloud water accretion and collection of snow and ice crystals; accretion was the most important growth process. Rain water was produced by melting of graupel. At the supercooled level, the accretion growth of graupel was dominant. The upper-level ice and snow seeded the middle cloud. The rich supercooled water promoted the accretion growth of ice crystals. It was shown that the cloud water was mainly consumed by collection by raindrops, accretion by snow and graupel. (3) Regarding the precipitation mechanism, rain water came mainly from melting of graupel and had little to do with the warm cloud process. Therefore, precipitation was dominated by the cold cloud process, which was consistent with observations. |
| Keywords: | Microphysical structure Growth of particles Precipitation mechanism Numerical simulation |
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