廊坊市地温变化特征分析

Change Characteristics Analysis of Ground Temperature in Langfang City

利用廊坊市1980—2015年间地温、降水等观测数据,研究了该地区0~40 cm地温的年、月变化特征、0~320 cm地温的日变化特征及关键农时初、终霜冻日期变化等特征。结果表明,随年代变化,0、10、20 cm年平均地温呈上升趋势,40 cm层地温变化趋势特征不明显;大气降水量和0~40 cm层地温之间存在明显的相互影响关系,当年降水量为偏多或转偏多时,一般地温降低,当年降水量为偏少或转偏少时,地温以升高为主;0~40 cm层地温每年3月开始上升,7月达到峰点,随后逐步下降,在次年1月达到最低点,随年代变化,1—5月、11—12月地温升降幅度比较明显,值得关注;0~40 cm层地温日变化曲线峰、谷点随深度依次延迟2~5 h,80~320 cm层地温日变化曲线走势相反,10月至次年2月为下升趋势,4—7月为上降趋势;廊坊初、终霜冻及10 cm地温稳定通过10℃日期随年代变化出现延迟和提前现象。

Based on the observation data of ground temperature and precipitation in Langfang City from 1980 to 2015,the annual and monthly change characteristics of ground temperature of 0 cm, 10 cm ,20 cm and 40 cm ,the daily change characteristics of 0-320 cm ground temperature and first and last frost date etc. were analyzed. The results showed that the annual mean ground temperature in 0 cm, 10 cm and 20 cm ground temperature presented increasing trends,and there was no obvious change trend of 40 cm ground temperature.There were significant interaction influence relationships between precipitation and ground temperature of 0 cm, 10 cm,20 cm and 40 cm.When the annual precipitation was more or turned to more,the ground temperature of 0 cm, 10 cm,20 cm and 40 cm decreased.When the annual precipitation was less or turn to less,the ground temperature of 0 cm, 10 cm,20 cm and 40 cm increased. The ground temperature of 0 cm, 10 cm,20 cm and 40 cm began to rise in March each year, and reached the peak in July, then turned to decline, reached the lowest point in January of the next year. With the change of years, the increasing and decreasing amplitudes of ground temperature from January to May and from November to December were more obvious ,which deserved to be paid more attention to. The peak and valley point of daily change curves of ground temperature in 0 cm, 10 cm,20 cm and 40 cm delayed 2-5 h with soil layer depth increase for all years and seasons, but had two contrary daily change curves with a decreasing trend from October to February of the next year and a increasing trend from April to July in 50 cm, 160 cm and 320 cm. With the change of years,the first and last frost dates delayed,the 10 cm ground temperature steadily passing 10 ℃ was ahead of time.