| 摘要: |
| 【 目的】为总结 2023 年 11 月 5—6 日通辽市极端暴雪的特点，为极端暴雪预报提供地参考经验。【方法】利用 常规观测资料、ERA5(0 . 25 °×0 . 25 °)逐 1 h 再分析资料和卫星云图资料，从天气学角度详尽地分析此次极端暴雪过程高低空 系统的生消演变、发展强度、水汽输送及辐合、水汽含量、动力条件等。不同于以往采用高空急流特征和卫星云图特征分析暴 雪的方法。【结果】此次极端暴雪过程具有持续时间长，降雪强度大，过程降雪量级极端性排列历史第 3 位，回流降雪等特点。 【结论】高空深厚冷涡、中低层低涡、高空急流出口区左侧偏差风强辐散、入海气旋爆发性发展、强劲低空急流近距离输送充沛 水汽是此次极端暴雪的有利环流形势。气旋东移北上入黄海再登陆吉林省东部转向东移入日本海。水汽通量维持异常大 值，从黄海近距离向通辽市输送丰沛水汽，在通辽市强集中辐合及维持，长时间的水汽供应和水汽辐合为极端暴雪提供异常 丰沛的水汽条件。低层 850 hPa 以下的东北急流和中层西南急流形成明显的垂直风切变和温度差异，产生强的动力锋生，也 加剧了垂直上升运动的发展，这种动力锋生和回流形势有利于提高降雪效率，与降雪最强时刻相对应。卫星云图上斜压叶状 云系演变为逗点云系再演变为螺旋云系。暖锋云系东西向拉长，形成明显的暖锋后弯特征。逗点云系和螺旋云系阶段对应 高低空系统强烈发展，降雪最强。 |
| 关键词: 极端暴雪；爆发性气旋；冷涡；急流 |
| DOI： |
| 投稿时间：2024-02-19修订日期：2024-07-08 |
| 基金项目:通辽市气象局科技创新项目(TQ202414) |
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| Analysis of Causes for an Extreme Blizzard Process in Tongliao City |
| zhaomeilan,SI Qin,YUAN Huimin |
| (Tongliao Meteorological Office of Inner Mongolia;Inner Mongolia Meteorological Observatory) |
| Abstract: |
| The causes of an extreme blizzard process in Tongliao City on November 5 - 6 , 2023 are analyzed based on conventional observation data , ERA5 0 . 25 °×0 . 25 °hourly reanalysis data and satellite cloud images to summarize the unique features of this extreme snowstorm and provide some references for future extreme snow forecasting. The generation and dissipation , development intensity , water vapor transport and convergence , water vapor content and dynamic conditions of the high- and low-level synoptic systems are investigated in detail from the perspective of synoptic meteorology. Different from previous blizzard analyses , the characteristics of high-level jet and satellite cloud images are focused on . The results indicate that the duration of this extreme blizzard was long , the snowfall intensity was high , and the extremity level of process snowfall ranked third in history , and there was the occurrence of backflow snowfall . The favorable circulation conditions for the extreme snowstorm included the
deep cold vortex in the upper air , the low vortex in the middle and low levels , the strong divergence of deviated wind on the left side of the exit area of the upper jet stream , the explosive development of the cyclone into the sea , and the near-distance transport of abundant water vapor by strong low-level jet. The cyclone moved eastward and northward into the Huanghai Sea before making landfall in eastern Jilin Province and turning eastward into the Japan Sea. The water vapor flux maintained an unusually large value conveying abundant water vapor from the Huanghai Sea to Tongliao City in a short distance , the strong convergence and maintained in Tongliao City , and the long-time water vapor supply and water vapor convergence provided unusually abundant water vapor conditions for this extreme blizzard . The northeast jet stream below 850 hPa and the mid-level southwest jet stream created significant vertical wind shear and temperature differences , causing the occurrence of strong dynamic frontogenesis and also exacerbating the development of the vertical upward motion . Such a dynamic frontogenesis and backflow situation helped increase the snowfall intensity corresponding to the time of heaviest snowfall . The satellite cloud images show that the baroclinic foliated cloud system evolved into a comma-dot cloud system and then into a spiral cloud system. The warm front cloud system elongated from east to west , forming an obvious warm front backbend feature . The comma-dot cloud system and spiral cloud system stage corresponded to the violent development of high- and low- level systems , when the heaviest snowfall was ongoing. During this process , the cyclone was strong and the cloud system was complete , deep and dense , belonging to the B type cyclone (B comma-dot cloud system ) |
| Key words: extreme snowstorm; explosive cyclone; cold vortex; jet stream |
