不同云微物理方案对一次飑线过程模拟的影响

本文利用WRF(Weather Research and Forecasting)模式的不同云微物理方案对2009年6月14日发生在华东地区的一次飑线过程进行1 km的高分辨率模拟,探讨不同云微物理方案对飑线模拟的影响。结果表明:双参数方案的模拟效果总体上优于单参数方案,其中WDM6方案模拟效果最佳,能够较好的模拟出强对流回波区、层云区的主要特征。在单参数方案中以WSM6方案最优。Kessler和LIN方案模拟飑线的回波范围偏小,强度偏弱。进一步对比热力和动力场发现,WDM6方案模拟的冷池的面积最大,强度最强,气压最高,飑线前部的入流处风速最大。不同云微物理方案对微物理场的影响较明显,相比单参数方案,双参数方案模拟的水凝物混合比更高,且能够模拟粒子数浓度,更准确地描述了云中的各类粒子特征。

Impact of different cloud microphysical schemes on a squall line simulation

By using the different cloud microphysical schemes of WRF (Weather Research and Forecasting) model, a squall line process occurred in East China on June 14, 2009 was simulated with high resolution of 1 km, moreover, the influence of different cloud microphysical schemes on the simulation of squall line was also analyzed. Results show that double moment schemes perform better than single moment schemes, especially WDM6 scheme, which can accurately simulate the strong convective echo and broad stratus cloud. The performance of WSM6 among single moment schemes obviously is the best, while Kessler and LIN scheme underestimate the range and intensity of the radar echo. The comparison of thermodynamic and dynamic field indicated that the range and intensity of cold pool, as well as the pressure and horizontal wind speed simulated by WSM6 reached their maximal values. Different cloud microphysical schemes have great influences on microphysical fields. The mixing ratio of hydrometeors of double moment schemes are higher than those of single moment schemes. Double moment schemes can also simulate the number concentration, and particle distribution accurately in the cloud.