AUTHOR=Chambers Joshua R. , Smith Mark W. , Smith Thomas , Sailer Rudolf , Quincey Duncan J. , Carrivick Jonathan L. , Nicholson Lindsey , Mertes Jordan , Stiperski Ivana , James Mike R. 

TITLE=Correcting for Systematic Underestimation of Topographic Glacier Aerodynamic Roughness Values From Hintereisferner, Austria

JOURNAL=Frontiers in Earth Science

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2021.691195

DOI=10.3389/feart.2021.691195

ISSN=2296-6463

ABSTRACT=<p>Spatially-distributed values of glacier aerodynamic roughness (<italic>z</italic><sub>0</sub>) are vital for robust estimates of turbulent energy fluxes and ice and snow melt. Microtopographic data allow rapid estimates of <italic>z</italic><sub>0</sub> over discrete plot-scale areas, but are sensitive to data scale and resolution. Here, we use an extensive multi-scale dataset from Hintereisferner, Austria, to develop a correction factor to derive <italic>z</italic><sub>0</sub> values from coarse resolution (up to 30 m) topographic data that are more commonly available over larger areas. Resulting <italic>z</italic><sub>0</sub> estimates are within an order of magnitude of previously validated, plot-scale estimates and aerodynamic values. The method is developed and tested using plot-scale microtopography data generated by structure from motion photogrammetry combined with glacier-scale data acquired by a permanent <italic>in-situ</italic> terrestrial laser scanner. Finally, we demonstrate the application of the method to a regional-scale digital elevation model acquired by airborne laser scanning. Our workflow opens up the possibility of including spatio-temporal variations of <italic>z</italic><sub>0</sub> within glacier surface energy balance models without the need for extensive additional field data collection.</p>