不同微物理参数化方案对乌鲁木齐机场一次强降雪天气的数值模拟能力评估

Numerical Simulation of a Heavy Snowfall at Urumqi Airport with Different Microphysical Parameterization Schemes

摘要: 本文以0.25˚ × 0.25˚的NCEP再分析资料为初始场，利用WRF模式对2021年1月23日乌鲁木齐机场出现的强降雪天气过程进行数值模拟研究。模式采用不同微物理参数化方案进行敏感性试验，并与自动站降水数据和雷达基数据进行对比，并分析了此次强降雪天气过程中水凝物的时空演变特征。研究表明：Thompson方案更好的模拟出了本次强降雪天气过程，表现在模拟的降水的开始结束时间，降水量的大小和中雪出现时间都与实况最接近。对比雷达反射率来看，Thompson方案和WSM6方案模拟的回波区域偏大，强度偏强，Lin方案模拟的强度偏弱，综合来看Thompson方案的模拟结果更接近雷达实际探测数据。从云微物理特征上看，由于温度低，三种方案基本模拟出的都是冰相粒子，Lin方案模拟的雪、冰晶和霰的含量比较均衡，其中霰的含量是三个方案中最多的，Thompson方案模拟的雪含量最多，冰晶和霰含量很少，WSM6方案模拟的雪和冰晶含量多，其中冰晶含量是三种方案中最多的。

Abstract: In this paper, the NCEP reanalysis data of 0.25˚ × 0.25˚ was used as the initial field, and the WRF was used to numerically simulate the heavy snowfall weather process at Urumqi Airport on January 23, 2021. Different microphysical parameterization schemes were used to carry out sensitivity tests, comparing with automatic station precipitation data and radar base data, and analyzed the spatial and temporal evolution characteristics of water condensate during the heavy snowfall. The results show that the Thompson scheme can better simulate the heavy snowfall weather process, which shows in the beginning and end time of simulated precipitation, the size of precipitation and the occurrence time of moderate snow are the closest to the real situation. Comparing with the radar reflectance, the echo area simulated by Thompson scheme and WSM6 scheme is large and the intensity is strong, while the intensity simulated by Lin scheme is weak. In general, the simulation results of Thompson scheme are closer to the actual radar detection data. Looking from the micro cloud physical characteristics, because of the low temperature, three basic simulating scheme are ice phase particles, Lin, a scheme of simulation of snow, ice and sleet content is relatively balanced, among them the content of graupel is one of the most in the three schemes, Thompson scheme simulation of snow, the most abundant content of ice crystals and sleet rarely, WSM6 scheme simulation of snow and ice crystals content more, The content of ice crystal is the most among the three schemes.