Draw wire ice ablation trackers: measuring ice melt and motion

Several months ago we installed 4 new draw wire ice ablation trackers (DWIATs) on the Greenland ice sheet on behalf of the Geological Survey of Denmark and Greenland (GEUS) and the Institute for Marine and Atmospheric research Utrecht (IMAU). The DWIATs monitor surface lowering by melting, movement as a result of ice dynamics, and temperature (inside the sensor box). Melt and motion are interlinked, as more melt leads to greater amounts of water at the glacier bed, which can result in increased glacier motion. The accuracy of localisation by GNSS satellites is accurate, allowing for the identification of periodical speed-up events. The DWIATs can be further tailored to your needs by adding additional sensors.

DWIAT installation (photo Maurice van Tiggelen)

DWIATs are very rugged, and easy to install: 1) Assemble the tripod with hex keys. 2) Mount the sensor/logger box. 3) Drill a hole max. 14 m deep. 4) Lower the draw wire into the hole. 5) Switch on the system. The units’ batteries can be shipped without dangerous goods declaration, and allow solar charging at temperatures (well) below freezing. Even without recharging during dark winter months the trackers keep functioning for several months. Both software and hardware safeties are built into Greenland Guidance instruments; double measures to prevent battery discharge beyond critically low levels.

The units recently installed in Greenland transmit their data through the Iridium satellite network that has coverage at even the northern- and southernmost latitudes. The data feed straight into the Greenland Guidance data portal where they are displayed and made available for download on a private web page. If the instrument owners approve, the data can also be graphically displayed on (but not downloaded from) the public data portal. Naturally, the DWIATs also store their measurements locally in the datalogger, ready for read-out during the next field visit in one or several years.

The DWIAT data currently featured in our public data portal belong to GEUS who monitor the Greenland ice sheet mass balance in the PROMICE project.