颠覆列车强风数值模式参数敏感性对比分析

新疆的三十里风区是著名的风口,兰新线和南疆铁路线横穿此地,时有列车被强风颠覆,对铁路运输影响很大,急需大风精细预报。数值模式中有许多参数,如何确定改进预报最显著的参数是个问题。采用MM5V3模式做模拟实验,设计3重嵌套,最小格距3km,用30″数字高程数据生成模式地形。分析表明,3km格距模式分辨率对地形有较为精确的表达。无论东西剖面还是南北剖面,3km所预报的风场更为详细,风速预报更准确;不仅可以预报出强的下坡风,亦可以预报出地形波列。对强风预报而言,模式水平分辨率是一个敏感因子。

Contrast Analysis of Numerical Parameters Sensitivity in Train-Overthrowing Gale Simulation

Accurate forecast of gales is badly needed in the Sanshili Wind Area of Xinjiang, a famous wind area for its so extremely strong wind that the trains passing by are frequently overthrown. A study on numerical parameters' sensitivity of the MM5V3 model has been conducted with designed 3 nested domains (3 km, 9 km, and 27 km) and based on the 30″-DEM (digital elevation model). The simulation results show that the resolution of 3-km is capable of describing topography precisely, and the wind field with 3-km grid resolution is more detailed and the simulated wind speed is more precise as well. Therefore, the horizontal resolution of models is a sensitive factor for gale prediction.