湿Q矢量释用技术在登陆华东台风定量降水预报(QPF)中的应用研究

Study on the application of the moist Q vector interpretation technique to quantitative precipitation forecast(QPF) for landfalling typhoons in eastern China

利用湿Q矢量对数值预报模式输出的风场、温度场、温度露点场进行动力释用,并考虑地形强迫作用,得到一个独立于数值模式直接预报输出降水场的释用预报降水场即湿Q矢量释用(Q^MVIP)技术。结合2010—2014年汛期(6—9月)登陆我国华东14个历史台风降水实况资料以及华东区域中尺度模式(基于WRF V3.1)(简称WRF模式)预报产品,统计检验分析了Q^MVIP技术对登陆台风降水的定量预报能力。结果表明,Q^MVIP技术较WRF模式明显改善了对25.0 mm·(24 h)^(-1)以上及50.0 mm·(24 h)^(-1)以上降水的定量预报能力。进一步结合"菲特"台风(2013)登陆前后所引发的24 h累积降水场进行比较分析发现,Q^MVIP技术对台风暴雨落区、强度的反映能力均优于WRF模式。这表明,湿Q矢量释用技术可以在一定程度上弥补现有数值预报模式对登陆台风定量降水预报(QPF)能力的不足。

The wind, temperature and dew-point temperature outputs from a numerical prediction model are interpreted by moist Q vector dynamically. The roles of orographic forcing are considered. Finally, an interpreting forecast rainfall field is produced, which is isolated from the counterpart direct output by numerical prediction model, i.e., moist Q vector interpretation technique （termed as QMvIP）. Based on actual rain data of fourteen landfalling typhoons in eastern Chinaduring June to September from 2010 to 2014 and outputs predicted by eastern Chi- na regional mesoscale numerical prediction model, which is based on WRF V3.1（hereafter termed as WRF）, quantitative forecasting ability of QMvIP to precipitation associated with landfalling typhoons in eastern China is verified statistically. The resuhs show that the QMvIP forecast scores are higher than the counterparts of the WRF for rain with intensity over 25.0 mm·（24 h）^-1 and 50.0 mm·（24 h）^-1. Furthermore, combining the precipitation during landfall of typhoon Fitow （2013）, the comparisonsshow that the performances of QMvIP are better than the counterparts of the WRF in the context of reflecting falloutarea and intensity of the rain with intensity over 50.0 mm·（24 h）^-1. These verifications indicate that the Q^MVIP mayberemedy the deficit of the quantitative precipitation forecast （QPF） ability of current numerical models to landfall typhoons