南京机场两次降雪天气过程对比分析
Comparative Analysis of Two Snowfall Weather Processes at Nanjing Airport

2022年年初发生在苏皖南部地区两次不同量级的降雪天气，分别对南京机场运行产生了不同影响，利用相关气象资料及WRF模式，对这两种天气形势和物理量场进行对比分析。结果表明：暴雪产生在低空急流的左前方和700 hPa切变线的风速辐合区中，水汽通量散度的辐合区和上升运动场的合理配置是暴雪产生的重要原因。通过对比分析物理量场，得出南京机场大雪短期预报的着眼点：700 hPa温度0℃线基本上都要南压到31？N或以南地区，850 hPa温度0℃要南压到30？N以南，地面温度 ≤ 0℃，925~800 hPa温度 ≤ ？3℃或？4℃，700 hPa温度 < 0℃，800~700 hPa存在逆温；可以通过对近地面大气层中冻结部分降水混合比在可凝结成降水水汽混合比中的比例 ≥ 0.80作为判断雨雪分界线的参考。
In early 2022, two snowfalls of different magnitudes occurred in southern Jiangsu and Anhui provinces, which had different impacts on the operation of Nanjing Airport. Using meteorological data and WRF mode, this paper focused on the comparison and analysis of the weather condition and the physical quantity fields of two different situations. The results show that the snowstorm occurs in the front left of the low-level jet stream and in the wind speed convergence area of the 700 hPa shear line. And the reasonable configuration of the convergence area of the water vapor flux divergence and the rising motion field can be regarded as an important reason for the occurrence of the snowstorm. Through the comparative analysis of these two snowfalls of different magnitudes, the focus of the short-term forecast of heavy snowfall at Nanjing Airport is preliminarily drawn: the 700 hPa temperature 0？C line should basically be pressed southward to the south of 31？N, and the 850 hPa temperature 0？C should be southerly pressed to the south of 30？N, surface temperature ≤ 0？C, 925~800 hPa temperature ≤ ？3？C or ？4？C, 700 hPa temperature < 0？C, and there is a temperature inversion in 800~700 hPa. Ratio of mixing ratio of frozen precipitation in the near-surface atmosphere to the mixing ratio of water vapor that can condense into precipitation is very important, which can be used to determine the evolution of rain and snow boundaries.