DebDab: A database of supraglacial debris thickness and physical properties

Abstract. Rocky debris covers around 7.3 % of the global glacier area, influencing ice melt rates and the surface mass balance of glaciers, making the dynamics and hydrology of debris-covered glaciers distinct from those of clean-ice glaciers. Accurate representation of debris in models is challenging, as measurements of the physical properties of supraglacial debris are scarce. Here, we compile a database of measured and reported physical properties and thickness of supraglacial debris that we call DebDab and that is open to community submissions. The majority of the database (90 %) is compiled from 172 sources in the literature, and the remaining 10 % has not been published before. DebDab contains 8,737 data entries for supraglacial debris thickness, of which 1,941 entries also include sub-debris ablation rates, 177 data entries of thermal conductivity of debris, 160 of aerodynamic surface roughness length, 79 of debris albedo, 59 of debris emissivity and 37 of debris porosity. The data are distributed over 83 glaciers in 13 regions in the Global Terrestrial Network for Glaciers. We show regional differences in the distribution of debris thickness measurements in DebDab, and fit Østrem curves for the 19 glaciers with sufficient debris thickness and ablation data. DebDab can be used for energy balance, melt, and surface mass balance studies by incorporating site-specific debris properties, or to evaluate remote sensing estimates of debris thickness and surface roughness. It can also help future field campaigns on debris-covered glaciers by identifying observation gaps. DebDab’s uneven spatial coverage points to sampling biases in community efforts to observe debris-covered glaciers, with some regions (e.g. Central Europe and South Asia) well-sampled, but gaps in other regions with prevalent debris (e.g. Andes and Alaska). Debris thickness measurements are mostly concentrated at lower elevations, leaving higher-elevation debris-covered areas under-sampled, suggesting that our knowledge of debris properties might not be representative of the entire manifestations of debris across elevations. DebDab is an openly available dataset that aims at evolving and being updated with community submissions as new data of supra-glacial properties become available. Data described in this manuscript can be accessed at Zenodo under https://doi.org/10.5281/zenodo.14224835 (Groeneveld et al., 2024).