土壤水分纵向分布规律与层间相关性研究——以青藏高原地区为例

Study on the Vertical Distribution Characteristics of Soil Moisture and the Correlation between Stratification:Take the Tibetan Plateau as an Example

利用青藏高原土壤湿度逐时观测数据集,分析那曲和帕里两地区76个站点5、10、20、40 cm不同深度多年土壤水分垂直分布规律及层间关联情况,主要有以下4点发现:1)青藏高原地区土壤水分随深度增加呈现下降趋势,最大层间距下(5—40 cm)那曲地区平均降幅为0.041 cm^(3)/cm^(3),帕里地区平均降幅达到0.066 cm^(3)/cm^(3)。2)以标准差为土壤水分稳定性参考指标,那曲、帕里两地区最小值同为40 cm层深的0.023、0.022,降幅分别为0.028、0.024,表明随着土壤深度的增加,土壤水分变化趋于稳定。3)那曲地区土壤水分值较低,以各层均值为代表,均低于帕里地区。4)相邻层间土壤水分表现出较高的相关性,其中以那曲地区10—20 cm相关性最强,达0.9以上。参考那曲地区5—40 cm层间相关系数为0.53可知,层间差距越大,相关性越低。本文研究结果可以为青藏高原地区水土保持及土壤水分层间模拟提供参考依据。

Using the hourly observation dataset of soil moisture in the Qinghai Tibet Plateau,the vertical distribution characteristics and the correlation between stratification of soil moisture at different depths of 5,10,20,and 40 at 76 stations in the Nagqu and Pari regions were analyzed.The following four main findings were made:(1)Soil moisture in Tibetan Plateau showed an obvious downward trend with the increase of depth,with an average decrease of 0.041 cm^(3)/cm^(3) in the 5—40 cm layer depth span,and an average decrease of 0.066 cm^(3)/cm^(3) in Pali.(2) With the standard deviation as the reference index,the minimum value of Naqu and Pali was 0.023,0.022 with a depth of 40cm layer,with a decrease of 0.028 and 0.024 respectively,indicating that the soil moisture changes stabilized with the increase of layer depth.(3)The soil moisture value of Naqu is low,represented by the mean of each layer,Naqu is lower than that of Pali.(4)The soil moisture between adjacent layers showed a high correlation,with the strongest correlation of 10—20 cm in the Nagqu area,reaching over 0.9.Reference to the correlation coefficient between 5—40 cm layers in Naqu is 0.53,the greater the gap between layers,the lower the correlation.This paper found can provide reference for soil and water conservation and soil moisture stratification simulation in Tibetan Plateau.