WRF模式对翁源一次特大暴雨过程的模拟分析

Analysis of the Simulation of an Unusually Heavy Rain in Wengyuan Using the WRF Model

采用中尺度数值模式WRF对2010年5月6日翁源发生的特大暴雨过程进行数值模拟研究,结果表明:模式成功地模拟出翁源24 h累计积雨量和前2个强降水阶段的落区和量级,但在第3阶段出现漏报;充沛的水汽含量、持续的水汽输送、强烈的水汽辐合、深厚的湿层以及850 hPa高能舌和中尺度能量锋的存在为强降水提供了良好的水汽和热力条件;低层西南气流明显减弱,中高层吹西北风,翁源处于水汽辐散区,热力条件转差是第3阶段模拟效果偏差的重要原因。该次过程对流云发展旺盛,伸展高度高,具有暖云层剖面结构,属于积云为主的暖区暴雨过程。

Using the mesoscale numerical model of WRF,this work simulated and studied an unusually heavy rain that took place in Wengyuan on May 6,2010.The results are shown as follows.The model suc-cessfully simulated the 24-h accumulated rainfall as well as the rain area and magnitude of rain intensity for the first two raining stages but failed to depict relevant elements for the third stage.The abundant amount,sustained supply and intense convergence of water vapor,a deep moist layer,a highly energized tongue at 850 hPa and a mesoscale energy front provided good conditions of water vapor and thermodynamics for the in-tense rain.On the other hand,a much weakened low-level southwesterly and a prevailing northwesterly at the mid-and high-levels in the third stage resulted in the divergence of water vapor and reduced thermody-namic conditions over Wengyuan,playing an important role in causing poor simulation for the stage.In sum-mary,the study process was characterized by vigorous growth and elevated extension of convective clouds with profiles of warm cloud layers,which can be classified as a warm-sector heavy rain mainly consisting of cumulus.