西北地区东北部两次强降水的环流及云图对比分析

Circulation and Cloud Images Comparative Analysis of Two Severe Precipitation in the Northeastern Part of Northwest China

利用常规天气图、FY-2E、2G云图和物理量诊断对"12·07"暴雨和"17·02"暴雪进行诊断分析,结果表明:两次过程虽季节差异大,但天气系统配置、云型有相似特征,西南暖湿急流都十分强盛,且经向型特征明显。云型有"厂"字型或"倒三角"型的特征。若云系顶部出现几条东南—西北向带状云带时,预示着该云带易发展、加强为强降水云团;若云系右侧再出现新的中尺度对流云团,预示着新云团未来发展、加强迅速,产生更大的强降水可能性极高,它比短时强降水常提早约2~3 h出现。冷平流最强时刻与强降水时段相匹配,冷平流分布及走向与强降水落区分布特征有相似性,也是准确预测强降水落区的一个关键因子。

Routine weather maps,FY-2E and 2G cloud images and physical parameters diagnosis were used to analyze the ＂12.07 ＂heavy rain and ＂17.02＂ snowstorm. The results showed that： the seasonal differences in the two processes are large, but the weather systems and cloud types have similar characteristics, warm wet southwest jet is strong and the characteristic of meridional type is obvious in both processes. Cloud patterns have characteristics of ＂F＂ shape or ＂inverted triangle＂ shape. If several southeastern zonal cloud bands appear at the top of the cloud system, it indicates that the cloud band is easy to develop and strengthen to heavy rain cloud clusters. If new mesoscale convective cloud cluster reappear on the right side of the cloud system, that indicates new cloud cluster will develop in the future and strengthen rapidly, resulting in a high possibility of greater heavy precipitation, the appearance of new cloud cluster is often about 2-3 hours earlier than the occurrence of the short time heavy rainfall. The strongest moment of cold advection match with the heavy rainfall period, the distribution and direction of cold advection is similar to that of heavy rainfall area, and it is also a key factor in accurately predicting the heavy rainfall area.