| 华南一次暖区暴雨的演变及云微物理机制模拟研究 |
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| 引用本文： | 周文昊,陆春松,高文华,邓琳.华南一次暖区暴雨的演变及云微物理机制模拟研究[J].热带气象学报,2020,36(6):805-820. |
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| 作者姓名： | 周文昊 陆春松 高文华 邓琳 |
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| 作者单位： | 1.南京信息工程大学/中国气象局气溶胶与云降水重点开放实验室/气象灾害预报预警与评估协同创新中心，江苏 南京 210044 |
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| 基金项目： | 国家自然科学基金项目41775131国家自然科学基金优秀青年基金41822504江苏省自然科学基金杰出青年基金BK20160041 |
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| 摘 要： | 利用WRF v4.0中尺度模式及0.25 °×0.25 °高分辨率的GDAS分析资料，对2017年6月15日发生在华南的一次典型暖区暴雨过程进行数值研究。多源观测资料对比分析表明，Thompson aerosol aware云微物理方案与YSU边界层方案组合合理再现了此次暴雨的演变过程。观测与模拟的强风速下传、低层风场切变及降水之间存在较好的对应关系，强的雷达反射率与水汽通量散度中心一致。在中尺度对流系统（MCS）发展和成熟阶段，冷池的出流抬升是新生对流的重要触发条件，地形的动力抬升作用并非主导。云微物理分析指出，由于华南上空充沛的水汽及过冷雨水，雪的最大来源项表现为水汽凝华成雪，而霰的最大来源项为过冷雨滴碰并冰晶、雪并冻结成霰。在零度层之下的1.5 km区域，冰相粒子的融化率可达暖雨过程（1×10-4g/(kg·s)的2倍，暗示其在融化层对雨水形成的支配作用，而雪霰的重力沉降扮演了重要角色。此外，相变过程显著影响着大气的温度变化，当对流云底较低时，低层的水汽凝结将抵消雨水蒸发导致的冷却作用，减弱地面冷池的强度。
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| 关 键 词： | 华南暖区暴雨 演变特征 云微物理机制 数值模拟 |
| 收稿时间： | 2020-02-25 |
A MODELING STUDY OF THE EVOLUTION AND MICROPHYSICAL MECHANISMS OF A WARM-SECTOR HEAVY RAINFALL IN SOUTH CHINA |
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| ZHOU Wen-hao,LU Chun-song,GAO Wen-hu,DENG Lin.A MODELING STUDY OF THE EVOLUTION AND MICROPHYSICAL MECHANISMS OF A WARM-SECTOR HEAVY RAINFALL IN SOUTH CHINA[J].Journal of Tropical Meteorology,2020,36(6):805-820. |
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| Authors: | ZHOU Wen-hao LU Chun-song GAO Wen-hu DENG Lin |
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| Institution: | 1.Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration/ Collaborative Innovation Centre on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China2.State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China |
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| Abstract: | A prefrontal heavy rainfall in south China during 0600-1800 UTC 15 June 2017 is investigated using the Weather Research and Forecasting model v4.0 with high resolution (0.25 °×0.25 °) analysis data from the Global Data Assimilation System. Surface precipitation, wind profiler, weather radar observations and the retrieved precipitable water from ground-based GPS are used to evaluate the simulations by using five microphysical schemes, i.e., WSM6, WDM6, Thompson, Thompson aerosol aware, and Morrison, and three planetary boundary layer schemes, i.e., YSU, MYJ, and MYNN3. The Thompson aerosol aware microphysics combined with the YSU boundary layer reproduces well the precipitation process. Results show that the onset of heavy rainfall is consistent with the appearance of strong wind moving downward and low-level wind shear, and the center of strong radar reflectivity corresponds with that of moisture divergence. In the growth and maturity stages of mesoscale convective systems, the outflow of cold pool that is not related to terrain can trigger a new convection. Cloud microphysics analysis shows that at 1.5 km below the 0 ℃ layer, the conversion rate of ice-phase hydrometeor melting can reach twice that of the warm-rain process (1×10-4g/(kg·s)), indicating that it controls the rain formation in the melting layer, and the sedimentations of snow/ graupel particles play a critical role. Due to the abundant water vapor and supercooled rain water over south China, the largest source of snow is the deposition of water vapor, and that of graupel is the accretion of supercooled raindrop by ice crystal and snow then freezing into graupel. In addition, the phase change process significantly affects the temperature change of atmosphere. When the convective cloud base is low, the condensation of vapor in the lower layer will offset the cooling effect caused by the evaporation of rainwater and weaken the strength of ground cold pool. |
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| Keywords: | warm-sector heavy rainfall evolutionary characteristics microphysical mechanisms numerical simulations |
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