Prototype wireless sensors for monitoring subsurface processes in snow and firn

Abstract

The detection and monitoring of meltwater within firn presents a significant monitoring challenge. We explore the potential of small wireless sensors (ETracer+, ET+) to measure temperature, pressure, electrical conductivity and thus the presence or absence of meltwater within firn, through tests in the dry snow zone at the East Greenland Ice Core Project site. The tested sensor platforms are small, robust and low cost, and communicate data via a VHF radio link to surface receivers. The sensors were deployed in low-temperature firn at the centre and shear margins of an ice stream for 4 weeks, and a ‘bucket experiment’ was used to test the detection of water within otherwise dry firn. The tests showed the ET+ could log subsurface temperatures and transmit the recorded data through up to 150 m dry firn. Two VHF receivers were tested: an autonomous phase-sensitive radio-echo sounder (ApRES) and a WinRadio. The ApRES can combine high-resolution imaging of the firn layers (by radio-echo sounding) with in situ measurements from the sensors, to build up a high spatial and temporal resolution picture of the subsurface. These results indicate that wireless sensors have great potential for long-term monitoring of firn processes.

Monitoring snowpack SWE and temperature using RFID tags as wireless sensors

“…After March 23 rd , once the snowpack has melt entirely near the tags, the temperature of the lowest tags increases above 0 °C, as expected. These results confirm that RFID tags can monitor and spatialize the temperature, with 1 °C accuracy, opening another perspective for RFID tags to monitor the snowpack (e.g., Bagshaw et al, 2018).…”

“…The SWE variations can therefore be estimated from the phase delay variation, on a snowpack that is dry or almost dry, as with buried GPR or GNSS. Besides, we also use tags as small temperature sensors (like, for example, Bagshaw et al, 2018), to monitor the vertical temperature repartition of the snowpack. This study not only introduces a new concept of RFID contactless sensing, but it is the first study that validates it in a real environment on the long term.…”

Moving beyond the Technology: A Socio-technical Roadmap for Low-Cost Water Sensor Network Applications

“…For example, customized hydrological monitoring systems can now be built by researchers, water practitioners, and even hobbyists for whom expensive commercial hardware is out of reach, or have more tailored data and system requirements (An example: ). Especially for scientific research and environmental management, low-cost sensor networks can potentially mitigate the uneven distribution of monitoring sites–they are more likely and economically possible to cover data-scarce areas such as developing countries, rural regions, mountainous/upland headwater river systems, and extreme environments, e.g., ref , in a meaningful way.…”

A LHCP Printed Cross Dipole Antenna for Glacial Environmental Sensor Networks

“…RELATED WORKS Three previous projects had aims and methodologies similar to those of the Thwaites project except that they used different devices, frequencies, and the projects took place at different sites. These include the GlacsWeb project [1]- [8], Wireless Sensor (WiSe) system [9]- [10], and the Electronic Tracer (ETracer) project [11]- [13]. Table I provides a comparative analysis of these including some details of the surface receiver antenna design.…”

“…[11] designed a spherical sensor probe called ETracer to measure water pressure along the flow path of englacial water channels. Wireless transmissions were achieved from the subsequent devices: new ETracer, Cryoegg, [12] and ET+ [13] at a maximum range of 2000 m and sensor data were received using a Yagi antenna tuned at 151.6 MHz. Yagi antennas usually have narrow beamwidths with high gain.…”