山东冷涡暴雨主要环境参量分析

Analysis of the key environment parameters of cold vortex heavy rainfall in Shandong summer

摘要:

利用常规探空数据及地面观测资料,针对山东近10年夏季冷涡暴雨的主要环境参量特征进行分析。结果表明:(1)山东冷涡暴雨主要出现在6—7月,较东北晚1个月发生,主要分布在鲁西北和鲁中山区,有很强的年月际变化。(2)冷涡暴雨具有“低层高湿”的层结特征,不很强的静力不稳定条件,倾向在高的PW条件下发生,冷涡暴雨潜势预报需重视大气整层可降水量和低层高湿的水汽条件。(3)冷涡暴雨关键参数指标,ΔT850-500、PW和(T-Td)850阈值分别为22—27℃、40—65mm和1—7℃。暖云厚度阈值3000—4500m,越厚越有利,K、CAPE和CIN指数阈值分别为30—40℃、1000—2300J?kg-1和>-100J?kg-1。大部分冷涡暴雨是弱到中等强度的深层垂直风切变,最低阈值6m?s-1。(4)山东夏季冷涡暴雨各月环境参数不同,中等强度的深层垂直风切变和一定程度的弱对流拟制在冷涡暴雨中作用可能更加明显。上述工作构成了山东冷涡暴雨预报的基础,为预报冷涡暴雨提供参考。

Abstract:

Using the conventional sounding data and ground observation data, the key environmental parameters of the summer cold vortex heavy rainfall cases occurring in Shandong province in recent 10 years were analyzed. The results show that: (1) Cold vortex heavy rainfall mainly occurs from June to July in Shandong province, one month later than that in Northeast China. It is mainly distributed in the northwest and central mountainous areas of Shandong, with strong inter-monthly variation. (2) It has the stratification characteristics of high humidity in the low layer, and does not require strong static instability conditions and tends to occur under high PW conditions. The potential prediction of cold vortex heavy rainfall should pay attention to the whole atmospheric precipitable water and low layer high humidity water vapor conditions. (3)The threshold values of the key parameters of ΔT850-500, PW and (T-Td)850 are 22-27 ℃,40-65mm and 1-7 ℃ respectively. The threshold of warm cloud thickness is 3000-4500m, the thicker the better. The thresholds of K index, CAPE and CIN are 30-40 ℃, 1000-2300J ?kg-1 and >-100J?kg-1 respectively. The deep vertical wind shears of most cases are weak to moderate intensity in Shandong province, and the minimum threshold is 6 m?s-1. (4) It is different monthly for the key environmental parameters of cold vortex heavy rainfall in Shandong province summer, and the moderate intensity deep vertical wind shear and a certain degree of weak convection simulation may play more obvious role on it. The above work constitutes the foundation for the forecast of cold vortex heavy rainfall, and provides a reference.