五道沟地区1971—2020年地温月尺度变化及其对气温的响应

【目的】研究五道沟地区1971—2020年0~320 cm土层月平均地温变化及其对气温的响应。【方法】利用五道沟水文实验站1971—2020年月平均气温和月0~320 cm(0、10、40、80、160、320 cm)土层地温资料,采用线性倾向估计、M-K检验以及Morlet小波分析等方法,分析了该地区1971—2020年0~320 cm土层温度月尺度变化规律及其对气温的响应。【结果】①五道沟实验站1971—2020年各土层地温趋势变化,除6—9月,其余月份均呈增加的趋势,最大增幅在3月,最小增幅在10月;0~160 cm土层地温总体呈上升的趋势,0 cm增幅最大,160 cm增幅最小,320 cm总体呈下降趋势。②利用小波分析可知各层年均地温具有明显的3~6、8~12 a和15~25 a周期变化,其中以3~6 a和8~12 a尺度为主周期。③M-K突变检验表明,0、10、80、160 cm和320 cm各层年均地温均发生突变,突变的年份分别在2013、2016、2019、2017年和1972年,其中0、10 cm和80 cm土层突变后地温显著性上升。④不同深度的月平均地温对气温变化的响应存在明显的差异,0~80 cm地温对气温变化较为敏感;160 cm地温对气温变化敏感性较弱;320 cm地温基本不受气温变化影响。0~160 cm各层年平均地温间的相关性较好;320 cm地温与其余层地温相关性较差。【结论】各层月平均地温总体呈上升的趋势,不同月份地温具有不同的变化趋势;各层年平均地温序列具有明显的突变以及周期变化特征;随着土层深度的增加各层月平均地温与气温的相关性逐渐减小。

Change in Temperature Over the Past 50 Years at Wudaogou and Its Influence on Soil Temperature at Different Depths

【Objective】Soil temperature affects crop growth and biogeochemical processes in terrestrial systems,and understanding its variation is hence important to evaluate the impact of global warming on agricultural production and soil gas emissions.The aim of this paper is to analyze the change in soil temperature over the past 50 years at Wudaogou Hydrological Station in Anhui province,China.【Method】The analysis was based on data measured from 1971 to 2020.Monthly average temperature at different soil depths from 0 to 320 cm,as well as their relationship with ambient air temperature was analyzed,using linear trend estimation,M-K test and Morlet wavelet method.【Result】①The temperature at different soil layers has changed.Except in the period from June to September,soil temperature in other months has been in increase,with the largest increase seen in March and the least increase in October.Temperature in the depths of 0~160 cm has been increasing,with the increasing rate decreasing along the soil depth.In contrast,the temperature at the depth of 320cm has been dropping.②The wavelet analysis showed two dominant periods in the monthly-average temperature:3~6,8~12 a,and a further period of 15~25 a.③The M-K mutation test showed that the temperature at depths from 0 to 320 cm had undergone abrupt changes in 2012,2017,2016,2019 and 1972.④The temperature at different soil depths was correlated with ambient air temperature differently,with the temperature in the depths of 0~80 cm being more sensitive to air temperature.No correlation was found between the air temperature and soil temperature at the depth of 320 cm.【Conclusion】The monthly average temperature at different soil layers has been in increase over the past centuries,likely due to global warming,though the increasing rate and its correlation with air temperature varied with soil depth.