Abstract:
Based on the daily mean, maximum and minimum temperatures from six national stations in Dazhou from 1980 to 2023, the temperature variation characteristics during regional sharp cooling events in Dazhou were analyzed. Using upper-air data, cases of regional sharp cooling in Dazhou from 1980 to 2018 are statistically examined to extract and validate local forecasting indicators for sharp cooling. The results show that: (1) From 1980 to 2023, the frequency of regional sharp cooling events in Dazhou exhibited an increasing trend, with a rate of 0.15 events per decade, while the intensity also showed an enhancing trend, at a rate of 1.13 °C per decade. The intensification trend in winter was more pronounced than in spring and autumn. (2) Prior to sharp cooling events, the increase in mean temperature was more noticeable in spring and autumn than in winter. During the cooling events, both the mean maximum and minimum temperatures generally displayed a warming trend, with the maximum temperature rising notably in winter and the minimum temperature increasing more significantly in spring and autumn. (3) Four forecasting indicators demonstrated good performance in predicting regional sharp cooling events in Dazhou, including the average temperature in Dachuan before the cooling event, the 700 hPa temperature difference between Dachuan and Hami at 08:00 before the event, the 700 hPa temperature difference between Dazhou and Yinchuan at 08:00 before the event, and the 850 hPa temperature drop in Dachuan at 20:00 during the event.