近50年石家庄地-气温差变化特征

利用石家庄17个国家气象站1972—2021年逐日地面气温、0 cm地温资料，分析了石家庄地-气温差的变化特征，结果表明：(1)石家庄地-气温差从1月开始逐渐增加，5月达到最大值5.0℃,然后开始减小，12月达到最小值-0.8℃;地-气温差在11月到次年1月为负值；春、夏、秋季均为正值，夏季最大，春季大于秋季，冬季以负值为主；(2)石家庄多年平均地-气温差在1.6～2.6℃之间，平均为2.1℃;整体上东部大于西部。(3)近50年石家庄年平均地-气温差呈显著的减小趋势，变化速率为-0.14℃/10a;夏、秋、冬三季的减小趋势均非常显著，夏季的减小趋势最强；石家庄市区和近郊站点年和四季地-气温差的减少趋势更显著。本文结论对科学认识石家庄城市生态环境的变化具有参考意义。

Variation Characteristics of Shijiazhuang Ground-Air Temperature Difference in Recent 50 Years

Ground-air temperature difference is the main contributor to surface sensible heat flux. The change of ground-air temperature difference effectively reflects the change characteristics of surface sensible heat flux, which profoundly impacts atmospheric circulation, weather changes, agricultural production, and the ecological environment. Over the past half-century, Shijiazhuang’s climate is warming significantly, with the Urban Heat Island effect being obvious. Concurrently, the local climate and environmental effects are brought about by urbanisation and are also very significant. Studying the variation characteristics of the ground-air temperature difference can deepen our understanding of changes in the near-surface thermal environment in Shijiazhuang, providing a scientific reference for guiding agricultural production, as well as protecting and improving the urban ecological environment. Based on the daily ground air temperature, 0 cm ground temperature, and precipitation data from 17 national meteorological stations in Shijiazhuang from 1972 to 2021, the variation characteristics of the ground-air temperature difference in Shijiazhuang are analyzed. The results show that: (1) The ground-air temperature difference in Shijiazhuang increasingly rises from January, reaching a maximum of 5.0 ℃ in May, then begins to fall, reaching a minimum of -0.8℃ in December; The ground-air temperature difference is negative in January, November and December, and positive in other months. The average ground-air temperature difference in spring, summer and autumn is positive, with the maximum in summer and greater in spring than in autumn; The average ground-air temperature difference in winter is mainly negative. (2) The multi-year average ground-air temperature difference in Shijiazhuang is between 1.6~2.6 ℃, averaging at 2.1 ℃. Generally, the ground-air temperature difference in the east is larger than that in the west. (3) In recent 50 years, the annual average ground-air temperature difference in Shijiazhuang exhibits a significant decreasing trend, the rate of change is -0.14 ℃/10a. The ground-air temperature difference in summer, autumn, and winter in Shijiazhuang decreases significantly, with the most potent trend in summer. The decreasing trend of ground-air temperature difference in urban and nearly rural stations in Shijiazhuang is more evident. The conclusion of this article is of reference significance for scientifically understanding the changes in the urban ecological environment of Shijiazhuang.