Ground observations are critical in the validation of soil water content (SWC) estimates from both satellites and land surface models. Portable SWC sensors provide useful information to determine the amount of SWC in the topsoil layer for various applications; however, these probes are not accurate without site‐specific correction. In the present study, we examined and compared six different types of portable electromagnetic (EM) SWC sensors, including multiple sensors made by the same manufacturers, for a total of 16 EM‐based SWC probes equipped with portable data loggers. All SWC probes met the target accuracy after onsite correction—the RMSD was <0.025 m³ m⁻³. Using the two‐sample t tests, we observed that SWC data obtained from similar electrode lengths and from different manufacturers showed similar distributions over time with the same mean. Furthermore, using the maximize R method to combine SWC data from two different types of sensors increased the accuracy of the results. When datasets from two different types of sensors were combined, the Pearson's correlation coefficient (R value) and RMSD values were improved. The average R value improved from .930 to .945, and the RMSD decreased from 0.036 to 0.018 m³ m⁻³. These results indicate that, along with site‐specific correction, synergetic use of multiple manufacturers’ EM‐based SWC probes can improve the R value and reduce systematic bias.

中文翻译：

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沙质壤土中便携式土壤水分传感器的现场评估

地面观测对于验证卫星和地面模型中的土壤含水量（SWC）估计值至关重要。便携式SWC传感器提供有用的信息，以确定各种应用程序在表土层中SWC的数量；但是，如果不进行特定位置的校正，这些探针将不准确。在本研究中，我们检查并比较了六种不同类型的便携式电磁（EM）SWC传感器，包括同一制造商制造的多个传感器，总共比较了16种配备便携式数据记录器的基于EM的SWC探头。现场校正后，所有SWC探头均达到目标精度-RMSD <0.025 m ³ m ^-3。使用二次抽样t测试中，我们观察到从相似的电极长度和不同的制造商获得的SWC数据显示，随着时间的推移具有相似的分布，且均值相同。此外，使用最大化R方法合并来自两种不同类型传感器的SWC数据可提高结果的准确性。当将来自两种不同类型传感器的数据集进行组合时，Pearson的相关系数（R值）和RMSD值得到了改善。平均R值从0.930提高到.945，RMSD从0.036降低到0.018 m ³ m ^-3。这些结果表明，连同针对特定地点的校正，协同使用多个制造商的基于EM的SWC探针可以改善R 重视并减少系统偏见。