不同云微物理方案对台风“安比”降雨模拟的影响

Comparison of Five Cloud Microphysical Schemes on the Rainstorm Weather Induced by Typhoon Ampil

  • 摘要: 利用WRF3.9.1模式对台风“安比”于2018年7月23日至24日北上至37°N以北造成的河北东北部、天津等地的大暴雨过程进行模拟,并对比了不同云微物理方案模拟的台风路径、结构、降雨分布,分析了云内水成物混合比差异与垂直运动的关系。结果表明:①各方案均能较好模拟出台风北上时的结构和强度,其中Morrsion 2-moment方案对强降雨的时段、区域、中心雨量把握最准确。②台风主雨区云体内的云水粒子分布于0~8 km,0 ℃高度在4~5 km,说明云体内存在大量过冷水。③强降雨时段,各方案模拟的垂直上升速度与小时雨强有较好的对应关系。同时雨区云顶高达10~15 km,配合云团内的强上升运动,云中出现大量过冷水及固态水成物。④Thompson方案与Morrsion 2-moment方案的云霰混合比明显大于其他方案,并且云霰粒子、云水粒子在0 ℃以上有大量重合,二者是云中贝吉龙过程的关键因素,对降雨量有着直接影响。⑤各微物理方案模拟的云体内部垂直上升运动区强弱与小时雨强大小相关性较好。本研究可以为改进适用于台风的云微物理方案提供方向,还加深了云微物理过程对台风降雨的认识。

     

    Abstract: The mesoscale model (WRF3.9.1) model was used to simulate the heavy rainfall process caused by Typhoon Ampil in Hebei and Tianjin from July 23 to 24, 2018. In this study, the typhoon track, structure and rainfall distribution simulated by different cloud microphysics schemes were compared, and the relationship between the difference of mixing ratio of hydrometeors in clouds and vertical motion was analyzed. The results showed that: ①All schemes can well simulate the structure and intensity of typhoon as it moves northward. Morrsion 2-moment scheme is the most accurate one to reproduce the period, region, and center of heavy rainfall. ②The water particles in cloud body in major precipitation area of the typhoon are distributed in 0−8 km, and the height of 0 ℃ is in 4−5 km, indicating lot of supercooled water is in the cloud body. ③In heavy rainfall period, the simulated vertical velocities of all schemes are in good agreement with hourly rainfall intensity, and the cloud top in the rain area reaches 10−15 km, with large amount of supercooled water and solid hydrometeors in the cloud and strong upward movement within cloud cluster. ④The cloud graupel mixing ratio of Thompson scheme and Morrsion 2-moment scheme is significantly higher than that of the other schemes, and cloud graupel particles and water particles exhibit overlap above 0 ℃, which are key factors of the Bergeron process in clouds and have direct impactc on the rainfall. ⑤The intensity of the vertical upward movement in the cloud simulated by each microphysical scheme has a good correlation with hourly rainfall intensity. These results can not only provide ideology for improving the cloud microphysics impacting typhoon process but also help to improve the cloud microphysical parameterization schemes in typhoon simulations.

     

/

返回文章
返回