The understanding of the cloud processes of snowfall is essential to the artificial enhancement of snow and the numerical simulation of snowfall. The mesoscale model MM5 is used to simulate a moderate snowfall event i...The understanding of the cloud processes of snowfall is essential to the artificial enhancement of snow and the numerical simulation of snowfall. The mesoscale model MM5 is used to simulate a moderate snowfall event in North China that occurred during 20-21 December 2002. Thirteen experiments are performed to test the sensitivity of the simulation to the cloud physics with different cumulus parameterization schemes and different options for the Goddard cloud microphysics parameterization schemes. It is shown that the cumulus parameterization scheme has little to do with the simulation result. The results also show that there are only four classes of water substances, namely the cloud water, cloud ice, snow, and vapor, in the simulation of the moderate snowfall event. The analysis of the cloud microphysics budgets in the explicit experiment shows that the condensation of supersaturated vapor, the depositional growth of cloud ice, the initiation of cloud ice, the accretion of cloud ice by snow, the accretion of cloud water by snow, the deposition growth of snow, and the Bergeron process of cloud ice are the dominant cloud microphysical processes in the simulation. The accretion of cloud water by snow and the deposition growth of the snow are equally important in the development of the snow.展开更多
针对2016年7月26日发生在江苏北部的一次弱天气尺度强迫下强对流过程,选用WRF(Weather Research and Forecasting)模式中具有一定代表性的5种云微物理参数化方案进行模拟。结果表明,只有NSSL 1-momlfo方案能够较好地再现回波的位置、强...针对2016年7月26日发生在江苏北部的一次弱天气尺度强迫下强对流过程,选用WRF(Weather Research and Forecasting)模式中具有一定代表性的5种云微物理参数化方案进行模拟。结果表明,只有NSSL 1-momlfo方案能够较好地再现回波的位置、强度及层云区,其余四种方案模拟的回波与实况存在不同程度的差异。原因是不同方案模拟的热动力结构、水成物及相变潜热的空间分布存在差异,其中NSSL方案模拟的上升气流更强劲,冷池范围也更集中;水成物集中在一个狭窄的水平区域,雨水在中低层较多,雪粒子和霰粒子在中高层较多;与此相应,NSSL方案相变潜热释放最多,进一步加强了上升运动。展开更多
利用ECMWF再分析资料作为初始场和边界条件,用WRF(weather research and forecasting model,WRF)模式对新疆地区中亚低涡暴雨个例进行模拟,结合区域自动气象站每小时降水数据、CloudSat卫星2B-CWC-RO数据产品和FY-2E卫星TBB资料评估Lin...利用ECMWF再分析资料作为初始场和边界条件,用WRF(weather research and forecasting model,WRF)模式对新疆地区中亚低涡暴雨个例进行模拟,结合区域自动气象站每小时降水数据、CloudSat卫星2B-CWC-RO数据产品和FY-2E卫星TBB资料评估Lin方案、WSM 6方案、Thompson方案和WDM 6方案在新疆地区的适用性。结果表明:Thompson方案在小雨(0.1~5.0 mm)和中雨(5.1~10.0 mm)的12 h累积降水模拟中占有优势。4种云微物理参数化方案模拟的云顶亮温分布图均与FY-2E卫星观测十分相似,但在数值上均低于观测。从CloudSat剖面平均冰水含量的垂直分布情况看,Thompson方案模拟冰水含量在数值和高值区的高度上模拟效果最好,Lin方案的模拟效果最差。从3 km区域平均冰水含量的垂直分布情况看,Thompson方案模拟的云冰含量最高,WSM 6方案与WDM 6方案模拟的云冰含量次之,且两者的冰水含量-高度廓线图几乎重合,Lin方案模拟的云冰含量最低。展开更多
基金The authors benefited from discussions with Professors C.-H.Sui and Xu Huanbin.The comments of the three anonymous reviewers are acknowledged.This research was supported by the National Natural Science Foundation of China.(Grant Nos.40375036 and 40105006).
文摘The understanding of the cloud processes of snowfall is essential to the artificial enhancement of snow and the numerical simulation of snowfall. The mesoscale model MM5 is used to simulate a moderate snowfall event in North China that occurred during 20-21 December 2002. Thirteen experiments are performed to test the sensitivity of the simulation to the cloud physics with different cumulus parameterization schemes and different options for the Goddard cloud microphysics parameterization schemes. It is shown that the cumulus parameterization scheme has little to do with the simulation result. The results also show that there are only four classes of water substances, namely the cloud water, cloud ice, snow, and vapor, in the simulation of the moderate snowfall event. The analysis of the cloud microphysics budgets in the explicit experiment shows that the condensation of supersaturated vapor, the depositional growth of cloud ice, the initiation of cloud ice, the accretion of cloud ice by snow, the accretion of cloud water by snow, the deposition growth of snow, and the Bergeron process of cloud ice are the dominant cloud microphysical processes in the simulation. The accretion of cloud water by snow and the deposition growth of the snow are equally important in the development of the snow.
文摘针对2016年7月26日发生在江苏北部的一次弱天气尺度强迫下强对流过程,选用WRF(Weather Research and Forecasting)模式中具有一定代表性的5种云微物理参数化方案进行模拟。结果表明,只有NSSL 1-momlfo方案能够较好地再现回波的位置、强度及层云区,其余四种方案模拟的回波与实况存在不同程度的差异。原因是不同方案模拟的热动力结构、水成物及相变潜热的空间分布存在差异,其中NSSL方案模拟的上升气流更强劲,冷池范围也更集中;水成物集中在一个狭窄的水平区域,雨水在中低层较多,雪粒子和霰粒子在中高层较多;与此相应,NSSL方案相变潜热释放最多,进一步加强了上升运动。
