| 摘要: |
| 摘要：利用陕西省区域自动站常规观测资料、NCEP 0.25o×0.25o再分析资料、华山站地面雨滴谱观测资料、商洛市雷达观测资料，从宏观和微观两方面对2021年7月22-23日秦岭山区东部一次强降水过程的特征进行分析。结果表明：本次山区暴雨在实况上具有强降水范围小、持续时间长、短时雨量大、极易引发地质灾害的特点。本次山区暴雨发生在弱天气强迫和强层结不稳定的环境下，由地形抬升和850 hPa冷平流共同触发此次对流。高层辐散抽吸使得上升气流加强，合并商洛市山阳县特殊地形的增幅作用共同造成山阳县法官镇短时雨强的极端性，小尺度地形作用下风的辐合和温度差异使得强降水在局地长时间维持。强降水在微观层面上表现为高浓度的小雨滴和部分大雨滴的共同作用。850 hPa水汽通量在此次暴雨预报中具有一定的指示意义，22日20时山区强降水在发展之前，商洛市东南部水汽通量突增至20～30 g·cm-1·hPa-1·s-1。雷达上表现为商洛市北部和南部30～45 dBz的大片层积混合云回波长时间维持，局地回波云团的合并对应降水增强。 |
| 关键词: 短时强降水;秦岭山区;雨滴谱;水汽输送 |
| DOI： |
| 投稿时间：2022-01-07修订日期：2022-05-16 |
| 基金项目:陕西省自然科学基础研究计划项目（2022JQ-279） |
|
| Characteristics of a Short-Time Heavy Rainfall in Eastern Piedmont of Qinling Mountains |
| LIU Shengnan,FENG Dian,GUO Damei,Xiao Yiqing,Wang Jie,LIU Juju |
| (Shaanxi Meteorological Observatory,Xi’an 710016;China) |
| Abstract: |
| Abstract: Using the routine meteorological observation data, the 0.25o×0.25o NCEP reanalysis data, the raindrop spectrum observation data of Huashan Station and the radar data of Shangluo, the characteristics of a heavy rainfall process in the east of Qinling Mountains during July 22-23, 2021 was analyzed from both macro and micro aspects. The results show that this rainfall occurred in mountain area has the characteristics of small heavy rainfall range, long duration and large rainfall, which can easily cause geological disasters. This heavy rain occurred in the environment of weak weather forcing and strong stratification instability. The convective cells were triggered by the weak cold air on 850 hPa and the orographic uplift. The high-level wind divergence increased the rainfall. in Faguan Town. The convergence of wind and the gradient of temperature on the surface played an important role in sustaining the convective system. The microphysical information indicates that the surface heavy precipitation was composed of a high concentration of small raindrops and a few large raindrops. The intensity of water vapor transport on 850 hPa could have influence on the heavy rain. The water vapor flux increased to 20～30 g·cm-1·hPa-1·s-1 at 20:00 BT 22 July before the strong precipitation occured in mountain area. The radar echoes of 30~45 dBz maintained in the north and south of Shangluo and the heavy rain is related to the merger of echoes. |
| Key words: short-time heavy rainfall; Qinling Mountains; raindrop size distribution; water vapor transportation |
