WRF模式在天山地区模拟能力的敏感性评估

Evaluation on the Sensitivity of WRF Model in the Tianshan Mountains

为探寻天山地区气候模拟WRF(weather research and forecasting)模式中最优参数化方案组合,针对云微物理方案(MIC)、积云对流方案(CS)、行星边界层/近地面层方案(PBL/SLS)、陆面过程方案(LSM)以及长短波辐射方案(LSW)设计了6组季节尺度物理参数化方案敏感性试验,模拟时间设为2014-11-28-2015-12-01。利用地面气象站观测数据和GPM(global precipitation measurement)卫星降水数据(R≥0.6),对模式模拟的日最高、最低气温及降水进行验证。结果表明:WRF模式对气温的模拟效果较好,且对日最高气温(0.8<R<0.95)的模拟优于日最低气温(0.62<P<0.88),日最低气温对陆面过程方案和云微物理方案敏感。模式对降水(R≈0.6)的模拟效果一般,各方案间表现差异大。云微物理方案WSM 6-class计算量较小且能较好地模拟降水,积云对流方案Kain-Fristch无法准确处理天山地区强对流与复杂地形,夏季模拟出现日最低气温极大偏差和负值降水。得出的最优组合为:WSM 6-class(MIC)、Betts-Miller-Janjic scheme(CS)、Mellor-Yamada-Janjic scheme/Monin-Obukhov(Janjic Eta),scheme(PBL/SLS)、N0 AH(LSM)、Community Atmosphere Model(LSW)。

In this study,a sensitivity analysis of the weather research and forecasting model(WRF)to different physical options in the Tianshan Mountains was carried out to seek the best performance combination.Yearly simulations at seasonal scale from 28 th November,2014 to 1 st December,2015 were carried out.The station observations and GPM(Global Precipitation Measurement)satellite precipitation data(R≥0.6)were used to validate the simulated daily extreme temperatures and precipitation.This work showed that temperature was modeled by WRF well,the simulated results of daily maximum temperature(T2 max,0.8<R<0.95)were better than that of daily minimum temperature(T2 min,0.62<R<0.88),and T2 min was sensitive to land surface model and cloud-microphysical model.The simulated results of precipitation by WRF were not so ideal with low correlation coefficients about0.6(R≈0.6),and they were different from different schemes.The cloud-microphysical scheme WSM 6-class could be used to simulate precipitation well.Kain-Fristch cumulus/convective scheme could not be used to describe the strong convection and complex terrain in the Tianshan Mountains as we got the very large T2 min biases and negative values of precipitation in summer.The best performance combination was WSM 6-class(Cloud-microphysics),Betts-Miller-Janjic(Cumulus/Convective scheme),Mellor-Yamada-Janjic scheme/Monin-Obukhov(Janjic Eta)scheme(Planetary boundary layer/Surface layer scheme),NOAH(Land surface model),and Community Atmosphere Model(Longwave and shortwave radiation).