摘要
利用中尺度WRF模式,针对2013年12月14-15日海南岛东南沿岸(五指山山脉的迎风坡)出现的罕见暴雨过程,从地形角度出发设计了一组控制试验和两组敏感性试验,探讨地形对冬季暴雨的影响及可能机制。结果表明:WRF模式能够较合理地模拟出本次降水过程特征以及相关气象要素的变化过程。五指山脉可使对流层低层偏东风和东南风在山前加强、汇合形成辐合带并长时间维持,降水出现在辐合带上。在偏东气流影响下,地形促使其东侧出现有利于水汽抬升的"低层辐合、高层辐散"环流配置,同时阻挡了中低层暖湿气流向西输送,造成地形东侧水汽大量聚集,为暴雨发生发展提供动力条件和充足的水汽。地形均一试验进一步表明,地形高度及起伏共同作用对水平流场分布、垂直运动发展以及水汽输送等影响更为显著,对暴雨增幅作用更为明显,使得降水的分布形式更为复杂。
An unusual rainstorm process occurred in the southeast coastal of the Hainan Island(the southeastern windward side of the Wuzhishan Mountain) from 14 to 15 December 2013. To explore the influence and possible mechanism of topography on winter rainstorm, a control experiment and two sensitivity experiments were designed based on the weather research and forecasting(WRF) model from the cutting in half and unifying terrain height aspects, respectively. The results show that WRF model can simulate reasonably the characteristics of the rainstorm process and the temporal evolution of the related meteorological elements. The easterly and southeasterly winds in low layer of troposphere were strengthened in front of the Wuzhishan Mountain, and they combined the convergence zone for the long term, which was beneficial to rainfall. The convergence zone was consistent with precipitation area. Under the influence of the easterly wind, the terrain prompted the formation of circulation pattern with lower-level convergence and upper-level divergence in the east side of the Wuzhishan Mountain, which was conducive to the water vapor lifting. Meanwhile, the terrain blocked the transport westward of easterly warm and wet airflow in low and middle level, which led to gather in large water vapour over the east side of the mountain. All of the above provided the dynamic lifting and sufficient water vapor for the occurrence and development of rainstorm. Nevertheless, the uniform height experiment further suggested that the effects of topography on rainfall depended on the inhomogeneous of terrain height, so the combination of the height and fluctuation of terrain had a greater influence on the horizontal airflow field distribution, vertical motion development and the water vapour transportation, which could enhance obviously the rainfall and make the distribution of precipitation more complicated.
作者
杨薇
冯文
陈有龙
YANG Wei;FENG Wen;CHEN Youlong(Hainan Provincial Meteorological Observatory, Haikou 570203, China)
出处
《干旱气象》
2019年第5期781-789,共9页
Journal of Arid Meteorology
基金
海南省气象局技术提升项目(HNQXJS201802)
中国气象局预报员专项项目(CMAYBY2016-057)共同资助
关键词
冬季暴雨
数值试验
地形影响
winter rainstorm
numerical experiments
topographic influence
