Abstract
Understanding surface melt over the Greenland Ice Sheet (GrIS) is important for evaluating the effect of the changing global climate on humanity, and for forecasting sea level rise. We demonstrate a recently developed L-band passive microwave algorithm for the retrieval of snow liquid water and snow and firn density over the GrIS. The retrievals are performed using brightness temperatures from the ESA SMOS satellite. The density retrievals show potential for mapping the equilibrium line altitude of the ice sheet by determining where retrieved densities exceed typical seasonal snowpack density, thus indicating the presence of firn. We integrate snow liquid water retrievals over area and time to obtain water column maps and daily estimates of the surface liquid water present over Greenland. The integrated annual surface liquid water retrieved over the entire ice sheet compares on the same order as modeled estimates of total meltwater available in current literature. • L-band brightness temperatures from SMOS can quantify melt over Greenland • Retrieved firn/snow density can be used to map equilibrium line altitude (ELA) • Retrieved liquid water content can be used to calculate total liquid water • First known direct measurement of a surface mass balance component
Highlights
Global sea levels are rising, and current predictions suggest that the rate of sea level rise will continue to accelerate (Kopp et al 2016; Nerem et al 2018)
Our study demonstrated the feasibility of Soil Moisture and Ocean Salinity (SMOS)-based Ws and ρs retrievals over the Greenland Ice Sheet (GrIS), and the potential to map the Equilibrium Line Altitude (ELA) and estimate surface mass losses
We have shown that a simple twolayer snowpack, input to the LS-MEMLS forward model, provides an approximation of the near-surface physics of the entire GrIS sufficient for inversion in the retrieval algorithm
Summary
Global sea levels are rising, and current predictions suggest that the rate of sea level rise will continue to accelerate (Kopp et al 2016; Nerem et al 2018). It has been shown that the rate of GrIS mass loss is increasing and could contribute to 7-21 cm increase in Global Mean Sea Level (GMSL) by the end of the century (Oppenheimer et al 2019) Both the Surface Mass Balance (SMB) and glacier discharge (ice deposited from outlet glaciers directly into the ocean) contribute significantly to the mass balance of the GrIS, and the two are correlated (Rignot et al 2008). By integrating retrieved liquid water over time and area we estimate the volume of melt water on the GrIS as a function of time and as an annual total We discuss how this quantified total melt water re lates to the GrIS surface mass loss and to the SMB, and we discuss the limitations of the algorithm and uncertainty contributions.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
