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许娈, 何金海, 高守亭, 林青. 集合动力因子对登陆台风“莫拉克”(0908)暴雨落区的诊断与预报研究[J]. 大气科学, 2013, 37(1): 23-35. DOI: 10.3878/j.issn.1006-9895.2012.11156
引用本文: 许娈, 何金海, 高守亭, 林青. 集合动力因子对登陆台风“莫拉克”(0908)暴雨落区的诊断与预报研究[J]. 大气科学, 2013, 37(1): 23-35. DOI: 10.3878/j.issn.1006-9895.2012.11156
XU Luan, HE Jinhai, GAO Shouting, LIN Qing. Diagnostic and Predictive Studies of Torrential Rain Location Associated with Landfalling Typhoon Morakot (0908) Using Multi-Dynamical Parameters[J]. Chinese Journal of Atmospheric Sciences, 2013, 37(1): 23-35. DOI: 10.3878/j.issn.1006-9895.2012.11156
Citation: XU Luan, HE Jinhai, GAO Shouting, LIN Qing. Diagnostic and Predictive Studies of Torrential Rain Location Associated with Landfalling Typhoon Morakot (0908) Using Multi-Dynamical Parameters[J]. Chinese Journal of Atmospheric Sciences, 2013, 37(1): 23-35. DOI: 10.3878/j.issn.1006-9895.2012.11156

集合动力因子对登陆台风“莫拉克”(0908)暴雨落区的诊断与预报研究

Diagnostic and Predictive Studies of Torrential Rain Location Associated with Landfalling Typhoon Morakot (0908) Using Multi-Dynamical Parameters

  • 摘要: “莫拉克”是2009年登陆我国热带气旋中影响范围最广、造成损失最大的台风.“莫拉克”带来的强降水导致台湾南部发生50年来最严重的水灾,福建、浙江等省的部分站点过程雨量超过50年一遇.因此,在台风暴雨(强降水)预报中,能否准确把握其落区就显得尤为重要.本文首先利用中尺度非静力数值模式WRF对台风“莫拉克”进行高分辨率数值模拟(三层嵌套,最高分辨率为2 km).模式较好地再现了台风中心的移动路径、强度;模拟的降水分布区域与实况也较为相符.利用再分析资料及模拟的高分辨率资料对暴雨成因进行诊断分析,表明造成此次强降水过程的水汽主要由西南季风输送,并且垂直运动旺盛,贯穿整个对流层.根据集合动力因子预报方法,运用广义湿位温、对流涡度矢量垂直分量及水汽散度通量对暴雨落区进行了诊断和预报,发现广义湿位温等值线的“漏斗状”区域与暴雨落区对应关系显著;基于NCEP-GFS每日四次的预报场资料,利用对流涡度矢量和水汽散度通量做出的降水落区预报表明,二者对降水落区均有一定的指示意义.强降水主要位于对流层中低层对流涡度矢量垂直积分量的梯度大值区附近,其时间演变与观测降水的演变具有相当高的一致性;水汽通量散度抓住了垂直运动和水汽散度这两个引发暴雨的关键因子,对降水的发生范围和强降水极值中心的判断更为准确.这三个动力因子都可以为“莫拉克”台风暴雨(强降水)落区提供信号,对台风暴雨落区具有一定的诊断和预报意义.

     

    Abstract: Typhoon Morakot (0908), the most wide-ranging, disastrous typhoon to make landfall in China during 2009, caused flooding from rainfall in southern Taiwan and in parts of Fujian and Zhejiang provinces. Because the location of torrential rain is the focus of forecasters, the Weather Research and Forecast Model (WRF) is used in this study to simulate Typhoon Morakot at high resolution with triple two-way nesting in which the finest grid size is 2 km. This simulation agrees well with track, intensity, and precipitation distribution observations. Diagnostic analyses included the simulation result and reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). The southwest monsoon was determined to be the dominant contributor of water vapor. In addition, a strong updraft spreading through the entire troposphere resulted in heavy rain. On the basis of the multi-dynamical parameters forecasting method, generalized moist potential temperature, the vertical component of convective vorticity vector and moisture divergence flux were chosen to perform diagnosis and forecasting of this heavy precipitation event. The results reveal funnel-shaped areas of generalized moist potential temperature isolines in the vertical sections, which corresponds well with the strong precipitation region. By using four-times-daily NCEP-Global Forecast System (GFS) forecast products, the vertical integration of the vertical component of convective vorticity vector and moisture divergence flux in the middle and lower troposphere were calculated; both show some significance in the prediction of rainfall areas. The high-value region of convective vorticity vector integration gradient is in fair agreement with the rainfall area, and the time evolution of convective vorticity vector integration is rather coincident with the observed precipitation. The forecast made by moisture divergence flux is better capable of both locating the rainfall area and tracing the torrential rain center. All of the parameters show indicative signals for the heavy rain location of Typhoon Morakot, and they are of certain significance in the diagnosis and prediction of typhoon precipitation regions.

     

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