Tracking 3-d meltwater production and runoff from glacial bare-ice surfaces
IceMelt3D will track the production and fate of surface meltwater in glacial bare-ice areas to improve the skill of Surface Mass Balance (SMB) models in predicting melt and runoff from these locations of major ice loss. In these areas a porous, low-density ‘weathering crust’ (WC) often develops, which causes sub-surface melting and dramatically changes the surface albedo and hence melt rates, invoking a feedback loop. However, SMB models lack fundamental constraints on the production and fate of meltwater in bare-ice areas. 
IceMelt3D will focus on numerically quantifying ablation area processes, using the Queen Elizabeth Islands (QEI), Canada as a case study. The Action will develop the Regional Climate Model (RCM) ‘MAR’ for SMB reconstruction of the QEI ice caps.  The Action objectives are: (O1) Resolve WC dynamics by simultaneous field measurements of surface energy balance, albedo, melt rates and WC properties in a hydrologically-gauged supraglacial catchment on Sverdrup Glacier, Devon Ice Cap, QEI. (O2) Develop and validate a numerical, vertically-resolved model of WC dynamics linked with a new surface albedo model. (O3) Up-scale the hydrology of supraglacial drainage catchments using remotely-sensed measurements calibrated with in-situ measurements.  (O4) Implement the WC-albedo model within the surface scheme of MAR. (O5) Use MAR to reconstruct the SMB of the QEI ice fields, and validate the outputs. 
These objectives are linked under a unified framework of ablation processes that comprises WC structural properties, albedo, surface energy balance, light-absorbing impurities and hydrology. Only with simultaneous, numerical engagement across the framework will the full impact of ablation zone processes on runoff be captured. The Action will train the researcher in High Arctic glaciological fieldwork, numerical modelling and regional climate modelling, and will enable two-way transfer of knowledge between Canada and Europe on QEI SMB observations and modelling.