中国农业气象

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宇宙射线中子法在复杂下垫面土壤水分测量中的应用

武强,贺开利,罗孳孳,杜爱军,刘亮,唐云辉   

  1. 1.重庆市气象科学研究所,重庆 401147;2.重庆市长寿区气象局,重庆 401220;3.重庆市巴南区气象局,重庆 401320
  • 出版日期:2020-01-20 发布日期:2020-01-20
  • 作者简介:武强,E-mail:theodorus@yeah.net
  • 基金资助:
    重庆市社会事业与民主保障科技创新专项项目“基于服务定制的智慧农业气象移动app的研制与应用示范”(cstc2017shms-xdny80035);重庆市气象局科技计划项目“宇宙射线中子法在区域土壤水分测量中的应用研究”(QNJJ-201703);重庆市气象部门业务技术攻关项目“重庆茶叶气候品质认证技术研究与应用”(YWJSGG-201905)第一作者联系方式:武强,E-ma

Application of Cosmic-ray Neutron Method in Soil Moisture Measurement on Complex Underlying Surface

WU Qiang,HE Kai-li,LUO Zi-zi,DU Ai-jun,LIU Liang,TANG Yun-hui   

  1. 1.Chongqing Institute of Meteorological Sciences, Chongqing 401147, China; 2. Changshou Metereological Bureau, Chongqing 401220; 3. Banan Metereological Bureau, Chongqing 401320
  • Online:2020-01-20 Published:2020-01-20

摘要: 宇宙射线中子法是介于点测量与遥感监测的中尺度、非接触土壤水分测量方法。将测量点设于土壤异质性较大的山地地形下垫面,以烘干称重法为标准对比,以频域反射法为连续性观测对照,对宇宙射线中子法在复杂下垫面的测量进行对比研究。结果显示:在复杂下垫面条件下,宇宙射线中子法对区域土壤水分测量值与烘干称重法多点平均计算值所代表的真值间直线方程的拟合优度(R2)为0.8717,均方根误差(RMSE)为0.0159kg·kg-1,纳什效率系数(NSE)为0.854,说明宇宙射线中子法测量结果准确可信。宇宙射线中子法与频域反射法对较长时间序列的土壤水分变化趋势反映完全一致,且对降水过程引起土壤水分变化的响应,宇宙射线中子法灵敏性优于频域反射法。宇宙射线中子法能够应用于复杂下垫面的区域土壤水分测量,且具有不受土壤异质性干扰的优点,能够更好地反映中尺度土壤水分的平均状况。

关键词: 复杂下垫面, 宇宙射线中子法, 烘干称重法, 频域反射法, 土壤含水量

Abstract: The cosmic-ray neutron method is a mesoscale and non-contact method for measuring soil moisture with the observation scale as between point measurement and remote sensing monitoring. The measuring point was located on the mountainous terrain with significant soil heterogeneity. This study used the cosmic-ray neutron method under complicated terrain as the oven-drying method being the standard comparison, while the frequency domain reflection method being the continuous comparison. This study indicated that the result of the cosmic-ray neutron method is accurate on complex underlying surface. The determination coefficient of linear equation(R2), root-mean-square error(RMSE), Nash-Sutcliffe efficiency coefficient(NSE)between the value of soil moisture content measured by the cosmic-ray neutron method and the truth value represented by the multi-point mean value of the oven-drying method was 0.8717, 0.0159kg·kg-1 and 0.854, respectively. The cosmic-ray neutron method and the frequency domain reflection method were completely consistent with the trend of soil moisture change in a longer time series, and the sensitivity of the cosmic-ray neutron method was better than the frequency domain reflection method in response to changes of soil moisture caused by precipitation. In summary, the cosmic-ray neutron method can be applied to soil moisture measurement on complex underlying surfaces with the advantage of being undisturbed by soil heterogeneity and higher ability on reflecting the average soil moisture on the mesoscale.

Key words: Complex underlying surface, Cosmic-ray neutron method, Oven-drying method, Frequency domain reflectometry, Soil moisture