引入对流凝结潜热作用对非均匀饱和大气中非地转湿Q矢量的改进研究

Study on Improvement of Ageostrophic Wet Q Vector in Inhomogeneous Saturated Atmosphere by Considering Convective Latent Heating

结合2009年第8号台风"莫拉克"登陆福建省引发的强降水过程,通过考虑对流凝结潜热加热,探讨了对非均匀饱和大气中非地转湿Q矢量(Qum)的改进。结果表明:(1)2009年8月9日08:00(北京时,下同)～10日08:00台风"莫拉克"给浙江大部分地区和福建中北部地区带来了一次暴雨过程,WRF模式较成功地模拟出了此次强降水过程。(2)850hPa Qum矢量散度场对同期降水落区具有一定指示意义,散度辐合强度变化与降水强度变化趋势有一定的对应关系。(3)此次暴雨过程中伴有大量的对流凝结潜热释放,最大潜热中心主要位于600hPa。(4)考虑对流凝结潜热加热作用得到改进的Qum矢量,600hPa改进后的Qum矢量散度辐合区对同期降水落区的指示作用得到进一步增强,诊断能力也得到进一步提高。

Combining a torrential rainstorm process,which was caused by typhoon ＇Morakot＇（No.8 in 2009） landing Fujian Province,the improvement of ageostrophic wet Q vector in inhomogeneous saturated atmosphere（Qum） is carried out considering convective latent heating.The results are as follows：（1） Typhoon ＇Morakot＇ land at Fujian Province from 08：00 on 9 to 08：00 on 10 August in 2009,which cause wide range heavy rainfall in most of parts of Zhejiang Province and middle and north of Fujian Province.The precipitation process is successfully simulated by the Weather Research and Forecasting（WRF） model.（2） The divergence field of Qum vector on 850 hPa is a good indicator to the counterparts of the precipitation area.The variation of convergence intensity of Qum vector divergence is highly correlated with that of precipitation throughout the rainstorm.（3） There is a lot of convective latent heating release during this heavy precipitation process,and the maximum center located at 600 hPa.（4） Qum vector is improved by considering convective latent heating release.The analysis shows that the ability of simultaneously reflecting and diagnosing precipitation of the convergence field of the modified Qum vector divergence has been significantly enhanced.