超低空急流背景下的景德镇市大暴雨过程分析

Analysis of Heavy Rains under the Background of Ultra Low Level Jet in Jingdezhen

分析了超低空背景下景德镇市大暴雨的特征,主要结论如下:景德镇市的大暴雨与超低空急流关系密切,有超8成的大暴雨伴有超低空急流或准超低空急流。在超低空急流背景下的大暴雨分为梅雨型、台风型、冷锋型、低涡型、高空偏北气流型和涌线型等6种形势,以梅雨型和低涡型居多。暴雨主要与中低层切变线密切相关。梅雨型有南北两支气流及相伴的带状(块状)副热带高压,台风型要形成两高一低的阻塞形势。暖区中的低空急流易在地面诱发辐合线,在冷锋型、涌线型等形势中在辐合线附近触发强降水。在低涡移向的右前方和上下重合的低涡中心易出大暴雨。高空偏北气流型多发生在7-8月,低空急流将副高控制区的高能、高湿空气向东北方向输送,与高空偏北气流构成强不稳定,在低空多层辐合系统的作用下,出现强降水。大暴雨过程中不伴有超低空急流的有大风速型、7至8月辐合型、副高型和低槽+切变+低涡+中层西南急流型。

In this paper, the characteristics of heavy rain in Jingdezhen area under the background ofultra low level jet are analyzed and the main conclusions are as follows. The heavy rainstorm in Jingdezhen is closely related to the ultra low level jet, with over 80% of all heavy rain storms accompanied by ultra low altitude jet or quasi ultra low level jet. And the rainstorms can be divided into 6types： plum rains type, typhoon type,cold front type, low vortex type, high altitude northerly airflowtype and inrush line type. The majority of them are plum rains type and low vortex type. The rainstorms are closely related to the shear line of the middle and low level. The low level jet in the warmarea is easy to induce the convergence line on the ground, and the strong precipitation is triggerednear the convergence line in cold front type and surge line type. The high altitude northerly airflowpattern occurs mostly in 7 - 8 months. The low level jet flows the air with high energy and humidityto the northeast direction, and it is highly unstable when interactive with the north side airflow. As a result, strong precipitation occurs under the interaction area of multilayer convergence.