重庆江北机场一次强对流天气背景下雨雾成因探讨
Analysis of the Causes of Rain Fog under the Background of a Severe Convective Weather Event at Chongqing Jiangbei Airport

本文基于重庆江北机场气象自动观测资料、欧洲中心ERA5再分析资料、风廓线雷达探空资料及MICAPS常规气象资料，采用对比分析方法讨论了2019年4月19日重庆江北机场一次强对流背景下雨雾天气产生的成因。分析表明，强降水引起的雨雾天气应当同时满足强降水和大雾产生的两种条件才会发生。此次强降水伴雨雾过程主要是由于冷锋过境的冷空气触发强降水后，锋面又有所西伸维持导致本场在高湿状态下而形成的。特征可概括为以下几点：1) 从雷达回波的移动和减弱来看，强对流条件下的雨雾多发生在回波移动缓慢，回波强度有所减弱的时段。2) 冷锋过境的冷空气触发强降水后，锋面又西伸维持。3) 随着降水的持续，本场相对湿度达到97%以上且维持3小时以上。4) 本场的气压、风速变化保持相对平稳，过程气压浮动不超过2 hPa，10 Min平均风速稳定在2~3 m/s左右。
Based on the automatic meteorological observation data of Chongqing Jiangbei Airport, the ERA5 reanalysis data from the European Centre, the wind profiler radar sounding data, and the conventional meteorological data from MICAPS, this paper uses the comparative analysis method to discuss the causes of the rain fog weather under the background of a severe convective event at Chongqing Jiangbei Airport on April 19, 2019. The analysis shows that the rain fog weather accompanied by heavy precipitation should meet the conditions for both heavy precipitation and fog formation to occur. This process of heavy precipitation accompanied by rain fog was mainly due to the fact that after the cold air triggered by the cold front passed through, the frontal surface further extended westward and maintained, causing the airport to be in a high-humidity state. The characteristics can be summarized as follows: 1) Judging from the movement and weakening of the radar echo, the rain fog under severe convective conditions mostly occurs during the period when the echo moves slowly and the echo intensity weakens. 2) After the cold air triggered by the cold front passed through, heavy precipitation was triggered, and then the frontal surface further extended westward and maintained. 3) As the precipitation continued, the relative humidity at the airport reached above 97% and remained for more than 3 hours. 4) The changes in air pressure and wind speed at the airport remained relatively stable, with the air pressure fluctuation not exceeding 2 hPa during the process, and the 10-minute average wind speed stably at about 2~3 m/s.