近70a甘肃寒潮事件时空特征及其与AO关系OA

Based on daily minimum temperature data from 73 meteorological stations in Gansu Province and the Arctic Oscillation(AO)index series for the period of 1960-2025,this study employed linear trend analysis,the Mann-Kendall test,and Pearson correlation analysis to examine the spatiotemporal characteristics of cold wave events over the past nearly 70 years and their correlation with the AO.The results show that:(1)Spatially,cold wave events exhibited a distinct pattern of"more frequent in the north,less frequent in the south."High-frequen-cy areas were located in the Hexi Corridor,Gannan,and Longdong-Longzhong region,and these areas contracted toward higher elevations as cold wave intensity increased.(2)While extreme cold wave events decreased signifi-cantly in the Gannan Plateau and western Hexi Corridor,the frequencies of cold waves and strong cold waves in-creased locally in parts of Longdong and Longzhong.(3)Temporally,cold wave events displayed an overall de-creasing trend during the study period,with high-intensity events exhibiting pronounced declines.The frequency and duration of cold wave events followed a"decrease-increase-decrease"pattern over time.On a monthly scale,cold waves occurred primarily during the cold season,with notable decreases in February and April.(4)Spring cold wave events were significantly negatively correlated with the AO.The strength of this correlation weakened from the central region toward the western and southern parts of Gansu,with the Longdong-Longzhong area ex-hibiting the strongest statistically significant correlation.The mean response lag was approximately 15 days and was influenced by topographic conditions.These findings provide a scientific basis for improving agricultural frost protection and developing effective cold wave disaster prevention and mitigation strategies in Gansu Prov-ince.