Raw and processed helicopter-borne radio-echo sounding ice thickness data from the glaciers of the Khumbu Himal, Nepal (2019)

We present here a new helicopter-borne glacier thickness survey in Khumbu Himal, Nepal, flown by the British Antarctic Survey in 2019. The data consist of raw and processed radio echo sounding radargrams and associated survey measurements acquired using a mono-pulse dipole radar known as 'DELORES', and geolocated glacier thickness interpreted from these radargrams. Mountain glaciers provide an important service in sustaining river flows for large populations downstream of High Mountain Asia, but these glaciers are retreating, and their future is highly uncertain. Glacier thickness measurements are vital for accurate mapping of the remaining ice reserve and for predicting where and how fast it will decline under climate change, but such measurements are severely lacking in this region due to the difficulties of surveying in remote, high-altitude settings. We report on a uniquely extensive new glacier thickness dataset for 17 glaciers in the Khumbu Himal around Everest that our team from the British Antarctic Survey collected using a novel, low-frequency helicopter-borne radar. We succeeded in mapping ice thickness with a precision of around +/-7% for thicknesses of up to 445 m and spanning a total of 119 line-km. This approximately doubles the length of previous thickness surveys in High Mountain Asia. This research is supported by the following NERC fundings: - NERC International Opportunities Fund - Bedmap Himalayas - Reconnaissance (NE/L013258/1) - Polar Expertise - Supporting Development (NE/R000107/1 and NEB1348) - The Big Thaw (NE/X005267/1 and NEB2165)