| 基于指数滤波法估算沟道根区土壤水分 |
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| 引用本文： | 高晓东,赵西宁,张宝庆,吴普特.基于指数滤波法估算沟道根区土壤水分[J].水科学进展,2014,25(5):684-694. |
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| 作者姓名： | 高晓东 赵西宁 张宝庆 吴普特 |
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| 作者单位： | 1.西北农林科技大学水土保持研究所, 陕西杨凌 712100; |
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| 基金项目： | 国家自然科学基金资助项目(31172039);“十二五”国家科技支撑计划资助项目(2011BAD29B09)~~ |
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| 摘 要： | 为更加有效获取黄土高原沟道地形根区土壤水分信息，基于表层（0~20cm）土壤水分观测值，采用指数滤波法在样带和沟道尺度对根区（20~80cm）土壤水分进行估算。结果表明，指数滤波法能够较准确估算沟道根区土壤水分，但随着土层深度增加估算误差逐渐增大。当有根区土壤水分初始值时，估算精度明显提高，但主要集中在时间序列前期。指数滤波法关键参数特征时长T的最优值（Topt）随土层深度增加而增大，呈现每增加20cm，Topt值较20~40cm增加1倍的变化规律。对于根区某一土层，不同空间位置（样带）和尺度Topt交换使用没有明显降低土壤水分估算精度，表明指数滤波法对Topt的空间敏感性较弱。需注意黄土高原区域尺度土壤性质具有极强空间异质性，指数滤波法在更大尺度上对Topt的敏感性需进一步深入研究。
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| 关 键 词： | 指数滤波 根区 土壤水 沟道 黄土高原 |
| 收稿时间： | 2014-03-09 |
Estimation of root-zone soil moisture over gullies using an exponential filter |
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| GAO Xiaodong,ZHAO Xining,ZHANG Baoqing,WU Pute.Estimation of root-zone soil moisture over gullies using an exponential filter[J].Advances in Water Science,2014,25(5):684-694. |
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| Authors: | GAO Xiaodong ZHAO Xining ZHANG Baoqing WU Pute |
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| Affiliation: | 1.Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China;2.Institute of Soil and Water Conservation, CAS&MWR, Yangling 712100, China |
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| Abstract: | To obtain more effectively root-zone soil moisture over gullies of the Loess Plateau, this study used an exponential filter to estimate root-zone (20-80 cm) soil moisture at transect and gully scales based on surface observations (0-20 cm). The results showed that the approach reliably retrieved root-zone soil moisture whereas larger errors were observed at deeper layers. If the initial root-zone soil moisture was available, the estimation accuracy was improved to some extent. However, note that significant accuracy improvement was only observed at the first several points in soil moisture time series. The optimal characteristic time length T (Topt) increased with depth, and it generally increased by one factor compared to that in the 20-40 cm with an increase of 20 cm depth. Furthermore, as the Topt was exchanged to calculate root-zone soil moisture between transects and scales, the estimation accuracy only changed negligibly. This indicated the exponential filter method was non-sensitive to Topt. However, it is worth noting that strong spatial heterogeneity of soil properties exists at region scale on the Loess Plateau, the sensitivity of the exponential filter to Topt should be investigated at larger scales. |
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| Keywords: | exponential filter root zone soil moisture gully the Loess Plateau |
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