A Characterization of Greenland Ice Sheet Surface Melt and Runoff in Contemporary Reanalyses and a Regional Climate Model

High-resolution ice sheet surface mass-balance and spatiotemporal runoff simulations: Kangerlussuaq, west Greenland

“…The Greenland Ice Sheet (GrIS) plays an essential role in the Arctic hydrological cycle and for the individual Greenland catchment water budgets (Bing et al 2016;Hanna et al 2009;Langen et al 2016), where freshwater runoff is the hydrological link between snowmelt and ice melt and hydrographic and circulation conditions in fjords and the surrounding ocean (e.g., Rahmstorf et al 2005;Cullather et al 2016;Hansen et al 2016).…”

“…Modeling the GrIS surface water balance components, including SMB, is relatively well understood and documented in several studies (e.g., Cullather et al 2016;Ettema et al 2009;Fettweis et al 2013;Hanna et al 2008;Langen et al 2015;Mernild et al 2011;Vernon et al 2013). The physical mechanisms that connect climate and nonlinearities in meltwater retention and firn densification, feedbacks between hydrology and ice sheet dynamics, and internal runoff routing and storage, which all contribute toward transforming the various input contributions into a runoff hydrograph at the margin, while taking into account the seasonal flow changes and delays, are only weakly understood (e.g., Rennermalm et al 2013).…”

“…This is to evaluate the importance of rainderived, snow-derived, and glacier ice-derived runoff, and the spatiotemporal distribution of runoff within the Kangerlussuaq catchment. ERA-I atmospheric data at six-hour temporal resolution (precipitation twelvehour temporal resolution) were downscaled to three hourly, 5-km, gridded data sets using the MicroMet (Liston and Elder 2006a) meteorological downscaling algorithms and submodels: ERA-I was chosen because it well represented atmospheric and GrIS conditions (Cullather et al 2016), and because Langen et al (2015) showed promising results after a full evaluation estimating changes in ice sheet surface mass-balance for the drainage basin linked to the Godthåbsfjord (64°N) in southwest Greenland. These atmospheric forcing data were used to drive SnowModel over the entire GrIS.…”

Evaluation of Greenland near surface air temperature datasets

“…Inter-comparison of SMB components has been carried out among different RCMs and between RCMs and global reanalyses (Cullather et al, 2016;Rae et al, 2012;Vernon et al, 2013). The results from these studies point to a wide inter-model spread, which are related to differences in model parameterizations (e.g., snow and ice physics), model ice mask and forcing at the domain lateral boundaries.…”

Grand Challenges in Cryospheric Sciences: Toward Better Predictability of Glaciers, Snow and Sea Ice

“…Recent results show how local flow features can change the turbulent heat fluxes (Mott et al, 2015), and that terrain sheltering has significant small-scale effects on melt efficiency (Mott et al, 2016). It is generally accepted that regional melt and therefore also catchment runoff (Cullather et al, 2016) can be well described with calibrated models, often using empirical temperature index methods for snow melt. At the same time, physics-based energy balance models, which are preferable for their transferability to other environments and future climates, have shown a high sensitivity to meteorological input (Schlögl et al, 2016).…”