Cryoegg: a novel wireless instrument for exploring deep ice

Instrumentation used for polar science is subject to extreme technological challenges, which must be overcome to understand how the Earth is responding to climate change. This project will enable the investigation of one of the last frontiers on planet Earth: subglacial environments, the cold, dark, high pressure zones beneath kilometres of ice. These environments control how ice responds to increasing temperatures and contribute to rising sea levels, but are by nature extremely challenging to measure. The presence of liquid water in this sensitive zone can have a significant impact on ice sheet behaviour, but measuring and characterising the water is presently impossible. Our capacity for predicting future environmental change is therefore severely limited by a lack of suitable instrumentation, so this project will develop a unique sensor to measure liquid water beneath deep ice sheets.
Subglacial environments are investigated via narrow (<150 mm diameter) boreholes drilled by ice corers or melted by hot water jets. Traditionally, cabled sensors are implanted in the boreholes and measurements sent to the surface. In fast flowing sectors of ice sheets, however, the use of cabled sensors is problematic. Rapidly deforming ice severs connections with the surface, and retrieval of the sensors through a non-vertical shaft is impossible. Wireless sensors are therefore the only alternative, since they can transmit data without a physical connection. Radio frequency (RF) techniques have long been used to probe features within and beneath ice, and more recently, to transmit data through up to 2.5 km of cold, dry ice and 600 m of temperate, wet ice. RF is therefore a viable solution for transferring measured data to the surface, but the transmission properties of ice must be fully characterised before an appropriate transmission-receiver scheme can be designed and tested.
The design requirements for the sensor are complex but achieveable. It must be able to collect fundamental measurements of water beneath up to 2.5 km of ice, be free to move within meltwater present beneath the ice, and transmit data to the surface. The sensor suite must be able to operate in low temperature, high pressure conditions, with no external power supply for up to 12 months. The RF transmission must be efficient, able to pass through mixed media (ice, sediment, water, cracks), and received and recorded at the surface by a low power, small footprint receiver which can operate for prolonged timescales.
The project will build on previous research, which designed and tested prototype sensors for shallow ice applications. These were successful in the target environment, but cannot transmit through the deeper sectors of ice which ultimately influence global sea levels. The project must improve and optimise our prototypes through a targeted laboratory and field testing campaign, which will select a suitable sensor set, design a transmission scheme, and manufacture a sensor package which can measure liquid water beneath 2.5 km of ice and send data to the surface. The prototype developed by this proposal will be deployed at two locations in Greenland to measure subglacial meltwater. Through partnership with two international scientific programs, we can test and deploy the Deep Cryoegg via boreholes drilled into the ice sheet, to reveal important information about how ice sheets are responding to increasing temperatures. The project will harness RF Communications to collect data that will predict future environmental changes, and provide a crucial contribution to helping the UK Live with Environmental Change.

Multidisciplinary academic impact:
The technology that will be developed by this project is in high demand from researchers investigating subsurface environments, at the large scale: the Greenland and Antarctic ice sheets which have significant impacts on global sea levels; and the smaller scale, such as mountain glaciers which impact local and regional water sources and flood risk. In addition, the automated technology can eventually be linked with widespread monitoring of physical conditions across the Arctic, via an existing network of meteorological stations which could be equipped with receivers for the Cryoegg. The interdisciplinary strength of the research team will ensure the research has a broad reach and will be applied to enable high quality science in extreme environments on Earth, and eventually, beyond.

Industrial and non-profit agency impact:
The technologies developed during preliminary research attracted the interest of a number of river monitoring organisations, who need simple, low cost methods to characterise water. The sensors on board the Cryoegg will measure subglacial water, but can also be repurposed to measure UK river water. The sensors traditionally used to collect these data from rivers are expensive and require specialist operators. This limits their application to a small number of locations, since costs are prohibitive for the charitable organisations which conduct much local monitoring. Our work with Westcountry Rivers Trust has determined that versions of the Cryoegg can be used as a crude measure of water quality conditions in a number of catchments in the UK, and act as an early warning system for pollutant episodes. We must conduct proof of concept testing in target catchments, which will be accomplished by the PI, supported by the PDRA and research students from Cardiff
Eventually, the low cost sensors can be distributed across catchments for use by 'citizen scientists'. Our goal is to emulate and enhance the extremely successful 'Freshwater Blitz' programme, conducted by FreshwaterWatch, via the Earthwatch Institute. Here, volunteers are provided with simple tools to measure their local watercourse, and points are awarded for samples collected. We could enhance these programmes with a low-cost version of the Cryoegg.

Quality of life and societal benefits:
The direct measurements of water in the natural environment will benefit society in two ways: first by enabling an improved understanding of how glaciers respond to changing climate, and impact sea level rise, and secondly, by creating a tool which can be used for widespread monitoring of UK catchments. The first will ultimately inform how the UK will respond to environmental change, governing future development of the coastline and management of flood risk. The second will enable improved monitoring of river catchments at the local scale, improving response times to polluting events which impact water quality. The adoption of real-time monitoring and rapid response will enable treatment of pollution at source, rather than prior to release to consumers at water treatment plants. This should eventually reduce water treatment costs, and hence water bills for consumers.

Education and outreach:
The final impact of the research project will be delivered via education and outreach events. Dr Bagshaw is a STEM ambassador, who undertakes regular 'People Like Me' science talks at primary schools and youth groups. She uses her experience of polar fieldwork to educate and inspire young people, especially young women who may not consider engineering as an attractive career option. Adult audiences will be reached via Science Café talks in Cardiff, a talk at the 'Bluedot' science and music festival in Manchester, and participation in the 'Soapbox Science' festival, organised by the Cardiff Women in Science network.