Distributed Temperature Sensors Deployed in WyCEHG Focus Sites

This summer we deployed a fiber-optic temperature monitoring technology called Distributed Temperature Sensor (DTS) in the No-Name drainage in the Medicine Bow National Forest. DTS works on the principle that the optical properties of telecommunication-grade glass fiber cables vary with temperature. A laser sends light pulses down a protected fiber and a sensor records any changes in the character of the light pulse, then back calculates temperature at every meter along the fiber, which can be several kilometers long. This provides very high spatial resolution, unmatched by other environmental temperature sensing technologies. This stream Influxes of groundwater to the channel are identified where abrupt changes in temperature are revealed; temperature changes in the channel due to atmospheric induced warming and cooling occur gradually along the DTS system. This system can identify gains that may occur via return flow or subsurface lateral flow. Over the summer, we deployed a DTS leased from Center for Transformative Environmental Monitoring Programs (CTEMPS) in two of WyCEHG’s high-intensity study sites. In the No-Name Creek Watershed, the DTS was deployed on a steeply sloped 550 m reach of stream to look for temperature signals that indicate exchange between the surface water and groundwater. This watershed is severely effected by trees that have succumbed to the pine bark beetle, and therefore it was an arduous deployment requiring many WyCEHG volunteers to navigate the many fallen logs that crossed the stream. Once set up, the autonomous DTS system collected data every ten minutes for 16 days without a hitch. The rich temporal and spatial temperature data we collected allows us to identify zones of groundwater exchange, and investigate the stream’s response to solar radiation and the ambient environment. A second reach of stream –the Blair tributary – was also instrument with DTS to measure inflow along the channel through interpretation of small changes in bed temperature. The Blair tributary has a much shallower slope than No-Name, and it not affected by deadfall. Installation was much more straightforward, however a new challenge arose: beavers found and damaged the cables during measurement. Although the DTS instrument required quite a bit of work by many people to install, this turned out to be great benefit. We were able to involve many “volunteer” WyCEHGers including graduate students from a variety of disciplines and several Summer Research Assistantship Program (SRAP) pre-college students that were doing research apprenticeships over the summer. This was a valuable opportunity to expose students to the hydrogeophysics research that is fundamental to WyCEHGs mission and excite the next generation of scientists with hands-on field experiences.

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

本夏季，我们在梅迪博国家森林的No-Name排水沟中部署了一种名为分布式温度传感器（DTS）的光纤温度监测技术。DTS基于电信级光纤电缆的光学特性随温度变化的原理工作。激光将光脉冲发送至保护光纤中，传感器记录光脉冲特征的任何变化，然后反向计算出光纤沿线的每米温度，光纤长度可达数公里。这提供了极高的空间分辨率，其他环境温度传感技术望尘莫及。此溪流中的地下水流入通道被识别，其中突发的温度变化得以显现；由大气引起的增温和降温在DTS系统中沿通道逐渐发生。该系统可以识别通过回流或地下横向流动可能发生的增益。在整个夏季，我们从转型环境监测项目中心（CTEMPS）租赁了DTS，在WyCEHG的两个高强度研究站点部署。在No-Name溪流域，DTS被部署在一条陡峭的550米河段上，以寻找指示地表水和地下水之间交换的温度信号。该流域受到松树皮甲虫侵害的树木严重影响，因此部署过程极为艰辛，需要众多WyCEHG志愿者穿越横跨溪流的众多倒木。一旦设置完毕，自制的DTS系统每十分钟收集一次数据，连续运行16天，无任何故障。我们收集到的丰富的时间和空间温度数据使我们能够识别地下水交换区域，并研究溪流对太阳辐射和环境的响应。另一条溪流——布莱尔支流——也用DTS进行了仪器测量，通过解释床温的小幅变化来测量沿通道的流入。布莱尔支流的坡度比No-Name浅得多，且未受倒木影响。安装过程更为直接，然而新挑战出现了：在测量期间，海狸发现了并损坏了电缆。尽管DTS仪器安装需要许多人共同努力，但这最终证明是极大的益处。我们能够让许多“志愿者”WyCEHG成员，包括来自多个学科的硕士生和几位夏季研究助理计划（SRAP）的预科学生参与其中，这些学生在夏季进行了研究学徒实习。这是一个宝贵的机遇，让学生接触到WyCEHG使命至关重要的水文地球物理研究，并通过实践现场体验激发下一代科学家的热情。

原始项目数据可通过联系[e-mail]获取。