中文摘要：

为了更全面地认识鲁南地区历史极端暴雪发生发展的机制,利用常规探空和地面观测资料、FY-2E长波辐射资料（Outgoing Long-w ave Radiation,OLR）和NCEP/NCAR 1°×1°再分析资料,采用天气动力学分析方法,对2015年11月23-24日出现在山东省南部极端特大暴雪过程的成因和动力结构演变特征进行分析。结果表明：（1）此次降雪发生在回流形势下,对流层中层强西南低空急流、切变线及低层强东北风共同作用,造成异常强暴雪天气。（2）低层西南急流把水汽输送到鲁南地区,并在暴雪区上方产生强的水汽辐合中心,为本次特大暴雪提供了有利的水汽条件。（3）高低空急流耦合,高空槽前正涡度平流使得低层减压,产生上升运动,有利于暴雪发生发展。（4）西南低空急流与偏北风在鲁南上空辐合,是强降雪主要集中在该地区的重要原因。（5）强冷空气降温使得雨快速转雪,降雪持续时间长,导致强降雪发生。（6）OLR特征分析表明,OLR 3 h平均低值中心与3 h最大降雪中心存在明显的负相关关系。研究鲁南地区极端暴雪特征有助于提高该地区灾害性天气的预报能力,对防灾减灾有着重要意义。

英文摘要：

For a more comprehensive understanding to the influence mechanism of the occurrence and development of historical extreme snowprocess in south of Shandong province,the cause and the dynamic structure on a snowstorm event occurred in south of Shandong Province from 23 to 24 November 2015 was investigated by the dynamic diagnosis with the routine sounding and surface observation data,OLR data of FY-2E satellite,NCEP/NCAR 1° ×1° reanalysis data. The results showthat：（ 1） Under the return-flowsituation,the abnormal snow-storm occurred by the combined effect of the strong low-level southwest jet,shear line and northeast jet stream in the mid-troposphere.（ 2） The transfer of water vapor to southern Shandong via southwest low-level jet which also produced intense convergence center just above the sensitive area provided favorable water-vapor conditions for the occurrence of snowstorm.（ 3） The upper-level and the low-level jets were coupled. The positive vorticity advection in front of the trough lessened the pressure from low-level which caused its upward movement. It was conductive to the occurrence and development of snowstorm.（ 4） The southwest low-level jet and northerly winds had a convergence just over the southern area of Shandong. This was the main reason why the heavy snow-fall concentrated in this region.（ 5） It was the strong cold air that made the rain turn to snowinstantly,which also made the snowhave a long duration. The above two reasons accounted for the occurrence of the extreme snowstorm.（ 6） The OLR analysis showed that the 3 hours average minimum center of OLR was closely related to the 3 hours maximum center of snowfall. The study on the characteristics of historical extreme snowprocess in south of Shandong province contributes to prediction ability of severe weather in the region,and is of tremendous importance to the disaster control and reduction.