Abstract:

Based on daily surface meteorological station observations from 1991 to 2023, this study employed wavelet analysis and probabilistic and statistical methods to analyze the spatiotemporal characteristics of the Yunnan-Guizhou quasi-stationary front (YGQS front) during winter, investigate its relationship with the probability of freezing rain occurrence in Guizhou Province, and comparatively analyze the frequency, duration, onset time, and frontal position of the YGQS front associated with different types of regional freezing rain events. The results shows that, the number of days with YGQS front occurrences during winter exhibits an overall increasing trend, with an average of 50 days per winter. The YGQS front occurs most frequently in January and February. The occurrence of the YGQS front increases the probability of freezing rain in Guizhou Province, and its association with freezing rain becomes stronger as the spatial extent of freezing rain increases. Most regional freezing rain events are accompanied by the YGQS front, and the durations of regional freezing rain events are generally shorter than those of the YGQS front. The whole province regional freezing rain events have the longest duration, averaging more than 10 days per year, whereas the other types typically last about 5 days per year. During most regional freezing rain events, the YGQS front occurs earlier than the freezing rain event and persists until or beyond its end. This feature is particularly evident for whole province and central-western regional freezing rain events. The YGQS fronts associated with different types of regional freezing rain events are generally located near the Yunnan-Guizhou border, on the Yunnan side, with the fronts associated with whole province regional freezing rain events exhibiting the greatest length.

Key words: Yunnan-Guizhou quasi-stationary front, freezing rain events, Guizhou Province, winter

摘要：

云贵准静止锋是冬季影响贵州省的重要天气系统，常导致该地区发生凝冻天气。基于1991—2023年逐日地面气象站观测资料，采用小波分析、概率统计等方法，分析冬季云贵准静止锋的时空特征，探讨云贵准静止锋与贵州省凝冻发生概率之间的关系，并对不同类型区域性凝冻过程与云贵准静止锋的发生频次、持续时间、起始时间及锋线位置进行对比分析。结果表明，冬季云贵准静止锋发生日数整体呈增加趋势，平均每年发生50 d，其中1月和2月发生日数最多。冬季云贵准静止锋的出现增加了贵州省凝冻发生的可能性，且随着凝冻影响范围的扩大，云贵准静止锋与凝冻之间的联系更为显著。多数区域性凝冻过程伴随云贵准静止锋活动，且区域性凝冻过程的持续时间通常短于云贵准静止锋的持续时间。其中，全省型区域性凝冻过程的持续时间较长，平均超过10 d·a^-1，其余类型平均持续时间约为5 d·a^-1。多数区域性凝冻过程中，云贵准静止锋早于凝冻过程发生，并晚于或同时与凝冻过程结束，这一特征在全省型和中西部型区域性凝冻过程中更为明显。不同类型区域性凝冻过程对应的云贵准静止锋锋线总体位于云贵交界处靠近云南一侧，其中全省型区域性凝冻过程对应的锋线最长。

关键词: 云贵准静止锋, 凝冻, 贵州省, 冬季