The Soil Moisture Active Passive Marena, Oklahoma, In Situ Sensor Testbed (SMAP-MOISST): Testbed Design and Evaluation of In Situ Sensors

In situ soil moisture monitoring networks are critical to the development of soil moisture remote sensing missions as well as agricultural and environmental management, weather forecasting, and many other endeavors. These in situ networks utilize a variety of sensors and installation practices, which confounds the development of a unified reference database for satellite calibration and validation programs. As part of the Soil Moisture Active Passive Mission, the Marena, Oklahoma, In Situ Sensor Testbed (SMAP-MOISST) was initiated to perform inter-comparisons and study sensor limitations. Soil moisture sensors that are deployed in major monitoring networks were included in the study, along with new and emerging technologies, such as the Cosmic Ray Soil Moisture Observing System (COSMOS), passive/active distributed temperature sensing (DTS), and global positioning system reflectometers (GPSR). Four profile stations were installed in May of 2010, and soil moisture was monitored to a depth of 1 m on an hourly basis. The four stations were distributed within a circular domain of approximately 600 m diameter, adequate to encompass the sensing range of COSMOS. The sensors included in the base station configuration included the Stevens Water Hydra Probe, Campbell Scientific 616 and 229, Decagon EC-TM, Delta-T Theta Probe, Acclima, and Sentek EnviroSMART capacitance system. In addition, the Pico TRIME system and additional time-domain reflectometry (TDR) systems were deployed when available. It was necessary to apply site-specific calibration to most sensors to reach an RMSE below 0.04 m3 m−3. For most sensor types, a single near surface sensor could be scaled to represent the areal-average of a field domain by simple linear regression, resulting in RMSE values around 0.03 m3 m−3.

Raw project data is available by contacting [e-mail]

现场土壤湿度监测网络对于土壤湿度遥感任务的发展、农业和环境管理、天气预报以及众多其他领域的推进至关重要。这些现场网络采用多种传感器和安装实践，这给建立统一参考数据库以供卫星校准和验证计划带来了一定的复杂性。作为土壤湿度主动被动任务（Soil Moisture Active Passive Mission）的一部分，位于俄克拉荷马州马雷纳的现场传感器测试平台（SMAP-MOISST）被启动，旨在进行相互比较和研究传感器的局限性。研究包括了部署在主要监测网络中的土壤湿度传感器，以及新的和新兴技术，如宇宙射线土壤湿度观测系统（COSMOS）、被动/主动分布式温度传感（DTS）和全球定位系统反射计（GPSR）。2010年5月安装了四个剖面站，并对土壤湿度进行每小时一次的监测，这些站点的分布覆盖了一个直径约600米的圆形区域，足以包含COSMOS的传感范围。基础站配置中包含的传感器有斯蒂文斯水 Hydra 探头、坎贝尔科学616和229型号、Decagon EC-TM、Delta-T Theta 探头、Acclima以及Sentek EnviroSMART 电容系统。此外，当可用时，还部署了Pico TRIME系统和额外的时域反射计（TDR）系统。对于大多数传感器，需要对大多数传感器进行特定地点的校准，以达到均方根误差（RMSE）低于0.04 m3 m−3的要求。对于大多数传感器类型，通过简单的线性回归，可以将近地表的单个传感器扩展以代表一个区域平均的场域，从而得到RMSE值约为0.03 m3 m−3。原始项目数据可通过联系[e-mail]获取。