2019年6月下旬中昆仑山北坡两场强降水对比分析

利用常规气象探测资料、NECP和EC高时空分辨率再分析资料，对2019年6月25日和28日出现在中昆仑山北坡两场强降水过程进行分析。表明：25日过程范围大、持续时间长的强降水，28日为分散、对流性强降水；两场天气过程影响系统有高空急流、中层低值系统、低层辐合线；25日强降水系统移动缓慢、冷空气从东西两侧进入昆仑山北坡，同时西太副高西侧西南风将大量水汽输送至昆仑山北坡，低层存在偏东和偏北、偏西风辐合；28日强降水低值系统移动迅速、对流层有逆温和不稳定，午后升温和低层弱辐合、山前偏北风是对流触发条件。中高层偏西偏南风水汽输送至昆仑山北坡上空，在低层合适的风场将水汽输送汇集到昆仑山北坡是强降水的关键，25日水汽输送强度和厚度明显强于28日。地形对于降水作用表现在热力和动力两方面。

Comparative analysis of two heavy precipitation events on the North Slope of Middl Kunlun Mountains in late June 2019

Based on data from conventional weather stations, NCEP and EC reanalysis with high time and spatial resolutions, two heavy precipitation events on the north slope of the Central Kunlun Mountains on June 25 and 28, 2019 were analyzed. The results show that the heavy rainfall event on the 25th is large-scale and long-lasting, and the event on the 28th is a convective severe precipitation. The influence systems of the two weather processes include upper level jet stream, middle level low value system and low level convergence line. On the 25th, the heavy precipitation system moved slowly with cold air entered the northern slope of Kunlun Mountains from the east and west sides, and the southwest wind from the west side of the West Pacific subtropical high transported a large amount of water vapor to the northern slope of Kunlun Mountains, and there was convergence of easterly, northerly and westerly winds at the lower level; on the 28th, the low value system of heavy precipitation moved rapidly, there was inversion and instability in the troposphere, and the warming in the afternoon, weak convergence in the lower level, and northerly wind in front of the mountain are the trigger conditions for convection. Through analysis, the key to heavy rainfall is the water vapor transported to the north slope of the Kunlun Mountains from the west to the south in the middle and high levels, and the water vapor transported to the north slope of the Kunlun Mountains by the wind field in the lower levels. The intensity and thickness of water vapor transport are significantly stronger on the 25th than on the 28th. With the analysis above, topography can affect the precipitation process in both thermal and dynamic aspects .