HEFEX III: UAV atmospheric profiles and ICON-LES simulations at Hintereisferner glacier (Austria)

This dataset contains UAV-based atmospheric profile observations and high-resolution atmospheric model simulations collected and produced during the first intensive observation period (IOP1) of the HEFEX III field campaign at Hintereisferner glacier.

The HEFEX III campaign investigated glacier–atmosphere interactions and boundary-layer processes over alpine glaciers using a combination of in-situ observations, remote sensing techniques, and high-resolution numerical modelling.

UAV observations (2025-08-07 to 2025-08-11)

The observational component consists of vertical atmospheric profiles obtained using uncrewed aerial vehicles (UAVs) equipped withan iMet XQ-2 meteorological sensors.

Temperature and humidity measurements were obtained with an iMet XQ-2 sensor package, providing measurements at a sampling rate of 1 Hz.

Observed variables include:

• air temperature
• potential temperature
• specific humidity

Wind information is derived from the UAV flight log and provided as 5-second averaged values, including:

• wind speed
• wind direction

During the campaign, UAV flights performed vertical ascents up to approximately 400 m above ground level.

Profiles were conducted every three hours, with an approximate ascent rate of 1 m/s, allowing high-resolution vertical sampling of the lower atmospheric boundary layer above the glacier.

Model simulations (2025-08-07 to 2025-08-11)

The dataset also contains large-eddy simulations performed with ICON in LES mode (ICON-LES) at a horizontal resolution of 51 m for the same time period as the lidar observations.

To enable direct comparison with the UAV measurements, the dataset provides model output extracted from the grid cells corresponding to the UAV profile locations.

The model data include the same atmospheric variables as the UAV observations where available, including:

• air temperature
• potential temperature
• specific humidity
• wind speed
• wind direction

Model values are provided for the lowest 50 model levels, corresponding to approximately 1300 m above ground level.

ICON-LES outputs are provided as instantaneous model values at full-hour timestamps, corresponding to the times of UAV profiling.

Data structure

The dataset contains:

• UAV-based atmospheric profiles from HEFEX III IOP1
• meteorological observations from the iMet XQ-2 sensor
• wind estimates derived from UAV flight logs
• ICON-LES model output extracted at the UAV profile locations
• UAV profiles aggregated to ICON model levels to facilitate direct comparison between observations and model output

The provided aggregation simplifies comparison between datasets but does not account for elevation offsets between the UAV launch location and the model topography.

Detailed descriptions of variables, units, file formats, and processing steps are provided in the accompanying README file.

Purpose

This dataset enables:

• evaluation of large-eddy atmospheric simulations against UAV-based observations
• investigation of the vertical structure of the atmospheric boundary layer over alpine glaciers
• analysis of temperature, humidity, and wind profiles in glacier-influenced environments
• comparison of observed and simulated boundary-layer dynamics during HEFEX III