【摘要】 中国传统“三伏时节”是大部分地区一年中气温最高、湿度最大的时期，研究该段时期的气候特征及其长期变化，对于指导农村农事活动和城市供水、供电以及市民消夏避暑，具有实际意义。利用石家庄国家气象站1955—2022年6—8月逐日气温、降水、相对湿度资料，分析了石家庄三伏时节的气候特点和变化趋势以及入伏日期早晚、中伏长短与汛期降水的关系。结果表明：1)初伏至中伏最热，极端最高气温出现在初伏，高温日数频数也在初伏最多，平均最大相对湿度出现在中伏，日均降水量和暴雨日数频数中伏最多，高温高湿的气候特征明显，末伏的温湿度依次缓降。三伏时节平均气温和相对湿度分别比夏季平均高0.1℃、10.1%。2)长三伏比短三伏更加闷热，降水和暴雨日数频数更多，长三伏的夏季降水比短三伏多12.8%。入伏日期偏早的年份，主汛期7—8月出现极端降水的概率更高，洪涝灾害发生的风险更大。3)三伏时节的气候变化有显著的增温、减湿趋势，但降水量的变化趋势不明显。更多还原

【Abstract】 The traditional “dog days” in China is the period of the highest temperature and highest humidity in most regions of the year. Studying the climate characteristics and long-term changes during this period is of practical significance for guiding rural agricultural activities, urban water and power supply, and citizens’ summer vacation. Based on the daily air temperature, precipitation, relative humidity data of Shijiazhuang national meteorological station from June to August during 1955 to 2022, the climate characteristics and change trends during the dog days, between the arrival date of the dog days with the length of the intermediate dog days and precipitation in the flood season were analyzed. The results showed that: 1) The hottest period usually occurred from the first to middle dog days, with the extreme maximum temperature and the most frequent high-temperature days both recorded in the first dog days. The highest average maximum relative humidity occurred in the middle dog days, and the highest average daily precipitation and the most frequent rainstorm days were also happened in the middle dog days, indicating prominent high-temperature and high-humidity. Both the temperature and humidity of the last dog days gradually decreased. The average temperature and relative humidity during the dog days were 0.1 ℃ and 10.1%, higher than that in summer, respectively. 2) The long dog days was more muggy than the short dog days, with more frequent precipitation and rainstorm days. The summer precipitation in the long dog days was 12.8% higher than that in the short dog days. The probability of extreme precipitation during the main flood season from July to August in years with the earlier arrival date of the dog days was higher, and the risk of flood disasters was greater. 3) There was a significant trend of increasing temperature and decreasing humidity during the dog days, but the trend in precipitation changes was not significant.更多还原