WRF/Chem模式起沙权重因子对沙尘模拟结果的影响

Influence of WRF/Chem Model’s Dust Emission Weight Factor on Dust Simulation Result

利用耦合了起沙模块的大气化学全耦合WRF/Chem模式,对2014年4月23—25日中国西北一次典型沙尘天气过程进行模拟,分析Shao2004起沙参数化方案(简称"Shao04方案")垂直沙尘通量公式中权重因子γ对沙尘时空分布特征的影响,并与气象卫星遥感监测沙尘范围以及站点颗粒物质量浓度进行对比分析,确定了较适用于中国西北地区Shao04方案的权重因子γ的取值。结果表明:(1)γ对沙尘质量浓度模拟范围和质量浓度中心值有影响,对垂直沙尘通量中心值的大小有影响;(2)不同γ取值都能很好地模拟出沙尘天气PM_(10)和PM_(2.5)质量浓度的趋势,但只有当γ=1时,即耦合Shao2011起沙参数化方案(简称"Shao11方案")的WRF/Chem模式能够较准确地模拟出中国西北沙尘过程中PM_(10)和PM_(2.5)质量浓度的变化。

A typical dust weather process occurring in Northwest China from 23 to 25 April 2014 was simulated by using the atmospheric/chemical full coupled WRF/Chem model coupled with the dust emission module.The influence of the weight factorγin the formulas of dust flux of Shao 2004 parameterization scheme(Shao04 scheme)on spatial and temporal distribution of dust was analyzed.The scope of simulated dust was compared with that monitored by FY-3C meteorological satellite remote sensing and dust mass concentration simulated by the model was compared with observations,the key parameter which was more suitable in the Shao04scheme for Northwest China was determined.The results are as follows:(1)The weight factorγhad a significant influence on the simulation of dust scope and maximum center value of mass concentration and vertical dust flux.(2)Differentγvalues could simulated the variation trend of PM10 and PM2.5 mass concentration well in dust weather,but only when the value was setted as 1,that is,WRF/Chem model coupled with Shao2011 sand parameterization scheme could simulate the change of PM10 and PM2.5 mass concentration more accurately during the dust process in Northwest China.