用调整边界层湍流系数的QNSE方案模拟夏秋季沿海大风的应用研究

Testing the QNSE scheme with the modified coefficients of turbulent mixing length scale:Three summer and autumn coastal gale cases study in China

利用WRF模式,采用YSU、QNSE边界层参数化方案以及调整参数后的QNSE边界层参数化方案(MQNSE),对2009年7月梅雨个例、2015年苏迪罗台风以及2013年10月的近海大风进行了模拟试验,并对模拟结果进行对比检验,着重检验参数调整后的QNSE方案模拟沿海大风效果.研究结果如下:参数调整后的QNSE边界层参数化方法改进了对沿海风场的模拟效果,尤其是当风速小幅脉动时,参数调整后的QNSE方案较接近于实况风速的波动.通过登陆台风个例模拟试验和对沿海10个岛屿观测站的490个样本统计检验表明,参数调整后的QNSE方案较YSU和原QNSE方案的绝对误差(AE)和相对误差(RE)小,表明调整后的方案对海上风速模拟能力有了一定提高.在对连续1个月的沿海风场模拟试验对比中发现,参数调整后,海上过大的风速模拟值明显降低,模拟效果更趋近于实况.

Accurate description of physical processes in the planetary boundary layer(PBL)is important for coastal gale simulations.In this study,the Yonsei University(YSU),Quasi-Normal Scale Elimination scheme(QNSE),and a modified QNSE planetary boundary layer scheme with adjusted coefficients of turbulent mixing length scale are used to simulate three coastal wind cases,namely Meiyu in July,2009,typhoon Soudelor(2015),and the coastal gale in October 2013.Results on Meiyu case show that the modified QNSE scheme improves the coastal winds simulations by producing time series of surface winds more close to the observations.The statistical results for 490 sample stations in ten islands for the typhoon Soudelor(2015)case show that the modified QNSE scheme produces the smallest absolute bias and relative bias compared to the QNSE and YSU schemes.The simulations of the coastal gale in October 2013 show that the modified QNSE scheme presents a reduction in the overestimated winds than the QNSE scheme.