摘要
以2018年3月4日影响浙江的初春罕见飑线过程为例,利用WRF模式与GSI-3DVar同化系统开展了雷达资料同化对重大强对流天气的影响研究,分析了雷达资料同化对此次飑线过程的模拟改进作用和可能影响过程,对比了雷达反射率因子和雷达径向速度的同化效果,探讨了不同数量和位置的雷达资料同化对模拟效果的影响。结果表明:雷达资料(尤其是反射率因子)同化有效改善了飑线边界层特征的模拟,从而改进了模式对飑线过程中组合反射率因子、降水、大风等发展演变的模拟效果。雷达反射率因子同化通过直接调整水凝物质含量,修正风暴中降水模拟及由此引起的蒸发冷却,形成更接近实况的强冷池,进而产生了比雷达径向速度同化更大的正贡献。相对于同化非关键区域的雷达资料,同化飑线过程上游关键区域的雷达观测所包含的重要中小尺度信息,对飑线过程模拟效果提升更为重要。
The impact of radar data assimilation on the numerical simulation of a rare squall line in Zhejiang Province on 4 March 2018 was studied in this paper.The weather research and forecasting(WRF)model and the gridpoint statistical interpolation three-dimensional variational(GSI-3 DVar)data assimilation system were used.In this study,multiple-Doppler radar data assimilation was applied to initialize a squall-line convective system,and its impact on the simulation was evaluated and discussed.The results showed as follows.Radar data(especially the radar reflectivity)effectively improve the simulation of the boundary layer characteristics of the squall line,which further improves the simulation effect of the composite reflectivity,precipitation and wind process of the squall line.Radar reflectivity assimilation,which directly adjusts the hydrometeors,improves the precipitation simulation in the storm and its induced evaporative cooling and forms a more intense cold pool close to reality,thus improving the simulation of the squall line.The radar reflectivity assimilation has a greater contribution than the radial velocity assimilation.Relative to assimilating radar data in non-critical areas,assimilating the small and medium-scale information carried by radar observations in key areas is more important for improving the simulation of the squall line.
作者
陈锋
董美莹
苏涛
冀春晓
CHEN Feng;DONG Meiying;SU Tao;JI Chunxiao(Zhejiang Institute of Meteorological Sciences,Hangzhou 310008)
出处
《气象》
CSCD
北大核心
2020年第4期462-477,共16页
Meteorological Monthly
基金
中国气象局气象预报业务关键技术发展专项[YBGJXM(2018)02-13]
浙江省气象科技计划项目(2018ZD01、2017ZD04)
浙江省科技计划项目(2017C03035)
浙江省基础公益研究计划项目(LGF20D050001)共同资助。
关键词
雷达资料同化
飑线
数值模拟
radar data assimilation
squall line
numerical simulation
