Meteorological variables (wind speed, air temperature and wind direction) were collected using two wind towers. Photogrammetric data were collected using a pole-mounted digital camera and DJI Phantom 3 UAV. LiDAR data collected via terrestrial and airborne laser scanning. Fieldwork carried out at Hintereisferner glacier, in the Oetztal Alps region, Tyrol, Austria, from 1-15 August 2018 by Joshua Chambers, Thomas Smith and Mark Smith. Terrestrial laser scan (TLS) data collected by Rudolf Sailer. Airborne laser scan (ALS) data originally from Open Data Austria, see Sailer et al. (2012). One wind tower recorded for the entire study duration, the second was moved to different plots every ~4 days. Photogrammetric data were collected on 8, 10, 11, 12 and 13 August. TLS scans were split into upper- and lower-glacier, and completed on 3, 7, 12 and 16 August. Data were used to examine the relations between glacier aerodynamic roughness and sampling resolution, and to develop a correction factor for roughness derived from coarser resolution data. Fieldwork was funded by an INTERACT Transnational Access grant awarded to Mark Smith under the European Union H2020 Grant Agreement No. 730938. Joshua Chambers is supported by a NERC PhD studentship (NE/L002574/1). Ivana Stiperski was funded by Austrian Science Fund (FWF) grant T781-N32.

Meteorological variables (wind speed, air temperature and wind direction) were collected using two wind towers. Photogrammetric data were collected using a pole-mounted digital camera and DJI Phantom 3 UAV. LiDAR data collected via terrestrial and airborne laser scanning. Fieldwork carried out at Hintereisferner glacier, in the Oetztal Alps region, Tyrol, Austria, from 1-15 August 2018 by Joshua Chambers, Thomas Smith and Mark Smith. Terrestrial laser scan (TLS) data collected by Rudolf Sailer. Airborne laser scan (ALS) data originally from Open Data Austria, see Sailer et al. (2012). One wind tower recorded for the entire study duration, the second was moved to different plots every ~4 days. Photogrammetric data were collected on 8, 10, 11, 12 and 13 August. TLS scans were split into upper- and lower-glacier, and completed on 3, 7, 12 and 16 August. Data were used to examine the relations between glacier aerodynamic roughness and sampling resolution, and to develop a correction factor for roughness derived from coarser resolution data. Fieldwork was funded by an INTERACT Transnational Access grant awarded to Mark Smith under the European Union H2020 Grant Agreement No. 730938. Joshua Chambers is supported by a NERC PhD studentship (NE/L002574/1). Ivana Stiperski was funded by Austrian Science Fund (FWF) grant T781-N32. ***** PLEASE BE ADVISED TO USE VERSION 2.0 DATA ***** The VERSION 2.0 data set (see ''Related Data Set Metadata'' link below) provides corrected glacier aerodynamic roughness calculated using the new model outlined in Chambers et al.

We present here the airborne Lidar data was collected over the Thwaites Glacier catchment and adjacent ice shelves during the 2018/19 and 2019/20 field seasons. The data was collected using a Riegl Q240i-80 scanning system mounted in the BAS aerogeophysically equipped twin otter aircraft. It provides a high resolution (0.2 to 0.4 points per m2), and high accuracy (~10 cm vertical) georeferenced and time stamped swath of surface elevation information. Each track is ~600 m wide. Such data provides critical information about how the surface of the Thwaites Glacier system is changing. The Thwaites 2019/20 aerogeophysical survey was carried out as part of the BAS National Capability contribution to the NERC/NSF International Thwaites Glacier Collaboration (ITGC) program, with additional funding for LIDAR data processing from the UK Foreign and Commonwealth Office.