Temperature profiles along the Whillans Ice Stream measured using a Distributed Temperature Sensor

Deep ice temperature profiles from fast moving sections of the Antarctic ice sheet provide important constraints on dynamic changes which affected the ice flow field within the recent centuries and millennia. One factor limiting the ability to collect such deep temperature profiles is the high failure rate for temperature sensors going through the process of re-freezing of a water-filled borehole. As a result, few such profiles exist. We present results from two 700-800m deep temperature profiles measured using a Distributed Temperature Sensor (DTS) and collected between January 2013 and December 2016. The DTS measures temperature using temperature-dependent scattering of a laser signal of known wavelength pulsed through a fiber-optic cable. It yields temperature measurements in one-meter increments along the length of the fiber within the borehole. Our measurements come from two boreholes located along the Whillians Ice Stream on the Siple Coast. Both DTS strings survived the freezing process and maintained integrity over the duration of the study enabling repeat temperature measurements of the ice column. Changes in our data from year to year reflect thermal recovery from the drilling and re-freezing process. They may also allow us to infer changes in the environment at the base of the ice.