青岛地区暖区暴雨特征研究分析

Characteristics of warm-sector rainstorms over the Qingdao area

利用2011—2018年常规和非常规气象观测资料,统计分析青岛地区38个暖区暴雨日的基本特征。结果表明:(1)青岛地区暖区暴雨按发生的天气形势主要可分为暖切变型、冷锋型、副高边缘I型及产生连续性暴雨的副高边缘II型。(2)暖区暴雨主要发生在7—9月,其中7、8月发生次数较高。暴雨落区和青岛的地形关系密切,在南北山区形成两条暖区暴雨高发生带。(3)暖区暴雨的强对流特征明显,短时强降水的贡献随总雨量的增加而加大,且降水时段集中,主要降水产生在6 h以内。(4)冷锋型和暖切变型的天气形势均为北部西风槽配合偏南的副热带高压,低层有明显的西南暖湿气流输送水汽,其中冷锋型有明显冷空气南下在华北南部形成东北西南向冷锋,而暖切变型的中支槽前在渤海西部有低涡生成,前部暖切位于半岛北部地区。两类副高边缘型均为西低东高形势,青岛处于副高西侧,且副高边缘II型的副高位置更为偏北,东移的西风槽更加深厚,与副高形成东西对峙,易出现连续性暴雨。(5)各型暖区暴雨基本发生在低层高能舌的顶端及由于风速切变和地形抬升造成的水汽辐合区域。

By using the conventional and non-conventional observation data from 2011 to 2018,the characteristics of 38 warm-sector rainstorms days over the Qingdao area were analyzed.Results show that:(1)according to the weather situation,the warm-sector rainstorms over the Qingdao area can be divided into four types,which are Cold-Front type(CF),Warm-Shear type(WS),Subtropical-High Edge typeⅠ(SH-Ⅰ)andⅡ(SH-Ⅱ)producing continuous rainstorms.(2)Warm-sector rainstorms mainly occur in July,August and September,with majority in July and August.Warm-sector rainstorms are closely related to topography,and two rain belts are formed in the southern and northern mountainous areas.(3)All the warm-sector rainstorms have strong convective.The contribution of short-term heavy rainfalls increases with the total rainfall,and the main precipitation period is concentrated into six hours.(4)The weather situations of WS and CF type both have trough in the north and subtropical high in the south,and the low-level southwest jets provide warm and wet air to the north.The cold air of CF type moves southward and forms a northeast-southwest cold front in the south of North China Plain,while the WS type has low eddies in the west of Bohai Sea and WS line in the north of Shandong peninsula in front of the trough.The SH-Ⅰand SH-Ⅱtype both have low in the west and high in the east.Qingdao is located on the west side of the subtropical high.When the subtropical high and the westerly trough are both strong enough,the continuous rainstorms will occur under the stable weather situation.(5)Warm-sector rainstorms in all types occur at the top of the low-level high-energy tongue and the water vapor convergence area caused by wind speed convergence or topographic uplift.