References of "Cryosphere Discussions (The)"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailAssessing spatiotemporal variability and trends (2000-2013) of modeled and measured Greenland Ice Sheet albedo
Alexander, P.; Tedesco, M.; Fettweis, Xavier ULg et al

in Cryosphere Discussions (The) (2014), 8

Accurate measurements and simulations of Greenland Ice Sheet (GrIS) surface albedo are essential, given the crucial role of surface albedo in modulating the amount of absorbed solar radiation and ... [more ▼]

Accurate measurements and simulations of Greenland Ice Sheet (GrIS) surface albedo are essential, given the crucial role of surface albedo in modulating the amount of absorbed solar radiation and meltwater production. In this study, we assess the spatio-temporal variability of GrIS albedo (during June, July, and August) for the period 2000–2013. We use two remote sensing products derived from data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS), as well as outputs from the Modèle Atmosphérique Régionale (MAR) regional climate model (RCM) and data from in situ automatic weather stations. Our results point to an overall consistency in spatiotemporal variability between remote sensing and RCM albedo, but reveal a difference in mean albedo of up to ~0.08 between the two remote sensing products north of 70° N. At low elevations, albedo values simulated by the RCM are positively biased with respect to remote sensing products and in situ measurements by up to ~0.1 and exhibit low variability compared with observations. We infer that these differences are the result of a positive bias in simulated bare-ice albedo. MODIS albedo, RCM outputs and in situ observations consistently point to a~decrease in albedo of −0.03 to −0.06 per decade over the period 2003–2013 for the GrIS ablation zone (where there is a net loss of mass at the GrIS surface). Nevertheless, satellite products show a~decline in albedo of −0.03 to −0.04 per decade for regions within the accumulation zone (where there is a net gain of mass at the surface) that is not confirmed by either the model or in situ observations. [less ▲]

Detailed reference viewed: 10 (0 ULg)
Full Text
See detailSmall impact of surrounding oceanic conditions on 2007–2012 Greenland Ice Sheet surface mass balance
Noel, Brice; Fettweis, Xavier ULg; van de Berg, W.J. et al

in Cryosphere Discussions (The) (2014), 8

During recent summers (2007–2012), several surface melt records were broken over the Greenland Ice Sheet (GrIS). The extreme summer melt resulted in part from a persistent negative phase of the North ... [more ▼]

During recent summers (2007–2012), several surface melt records were broken over the Greenland Ice Sheet (GrIS). The extreme summer melt resulted in part from a persistent negative phase of the North-Atlantic Oscillation (NAO), favouring warmer than normal conditions over the GrIS. In addition, it has been suggested that significant anomalies in sea ice cover (SIC) and sea surface temperature (SST) may partially explain recent anomalous GrIS surface melt. To assess the impact of 2007–2012 SIC and SST anomalies on GrIS surface mass balance (SMB), a set of sensitivity experiments was carried out with the regional climate model MAR. These simulations suggest that changes in SST and SIC in the seas surrounding Greenland do not significantly impact GrIS SMB, due to the katabatic winds blocking effect. These winds are strong enough to prevent oceanic near-surface air, influenced by SIC and SST variability, from penetrating far inland. Therefore, the ice sheet SMB response is restricted to coastal regions, where katabatic winds are weaker. However, anomalies in SIC and SST could have indirectly affected the surface melt by changing the general circulation in the North Atlantic region, favouring more frequent warm air advection to the GrIS. [less ▲]

Detailed reference viewed: 39 (2 ULg)
Full Text
See detailHybrid inventory, gravimetry and altimetry (HIGA) mass balance product for Greenland and the Canadian Arctic
Colgan, W.; Abdalati, W.; Citterio, M. et al

in Cryosphere Discussions (The) (2013)

We present a novel inversion algorithm that generates a mass balance field that is simultaneously consistent with independent observations of glacier inventory derived from optical imagery, cryosphere ... [more ▼]

We present a novel inversion algorithm that generates a mass balance field that is simultaneously consistent with independent observations of glacier inventory derived from optical imagery, cryosphere-attributed mass changes derived from satellite gravimetry, and ice surface elevation changes derived from airborne and satellite altimetry. We use this algorithm to assess mass balance across Greenland and the Canadian Arctic over the December 2003 to December 2010 period at 26 km resolution. We assess a total mass loss of 316 ± 37 Gt a−1 over Greenland and the Canadian Arctic, with 217 ± 20 Gt a−1 being attributed to the Greenland Ice Sheet proper, and 38 ± 6 Gt a−1 and 50 ± 8 Gt a−1 being attributed to peripheral glaciers in Greenland and the Canadian Arctic, respectively. These absolute values are dependent on the gravimetry-derived spherical harmonic representation we invert. Our attempt to validate local values of algorithm-inferred mass balance reveals a paucity of in situ observations. At four sites, where direct comparison between algorithm-inferred and in situ mass balance is valid, we find an RMSD of 0.18 m WE a−1. Differencing algorithm-inferred mass balance with previously modelled surface mass balance, in order to solve the ice dynamic portion of mass balance as a residual, allows the transient glacier continuity equation to be spatially partitioned across Greenland. [less ▲]

Detailed reference viewed: 21 (0 ULg)