Regional sea level change in response to ice mass loss in Greenland, the West Antarctic and Alaska

Abstract

Besides the warming of the ocean, sea level is mainly rising due to land ice mass loss of the major ice sheets in Greenland, the West Antarctic, and the Alaskan Glaciers. However, it is not clear yet how these land ice mass losses influence regional sea level. Here, we use the global Finite Element Sea‐ice Ocean Model (FESOM) to simulate sea surface height (SSH) changes caused by these ice mass losses and combine it with the passive ocean response to varying surface loading using the sea level equation. We prescribe rates of fresh water inflow, not only around Greenland, but also around the West Antarctic Ice Sheet and the mountain glaciers in Alaska with approximately present‐day amplitudes of 200, 100, and 50 Gt/yr, respectively. Perturbations in sea level and in freshwater distribution with respect to a reference simulation are computed for each source separately and in their combination. The ocean mass change shows an almost globally uniform behavior. In the North Atlantic and Arctic Ocean, mass is redistributed toward coastal regions. Steric sea level change varies locally in the order of several centimeters on advective timescales of decades. Steric effects to local sea level differ significantly in different coastal locations, e.g., at North American coastal regions the steric effects may have the same order of magnitude as the mass driven effect, whereas at the European coast, steric effects remain small during the simulation period.

A cold and fresh ocean surface in the Nordic Seas during MIS 11: Significance for the future ocean

“…Results of modeling experiments on a potential AMOC reaction to the fresh water input are contradictory, so far. Some of them showed a highly increased sensitivity of the AMOC strength [e.g., Hawkins et al, 2011;Brunnabend et al, 2015] in response to potential fresh water input, while others demonstrate only a minor effect [e.g., Ridley et al, 2005;Hu et al, 2011].…”

Quantifying the Sensitivity of Sea Level Change in Coastal Localities to the Geometry of Polar Ice Mass Flux

“…A number of factors contribute to the geographic variability of sea level change, including changes in ocean dynamics, thermosteric effects, land water storage, local vertical land movement due to tectonics and sediment compaction, and the melting of glaciers and ice sheets (Milne et al 2009), all of which are superimposed on large-scale, long-term geographic trends associated with ongoing glacial isostatic adjustment (Peltier 2004;Lambeck et al 2014). The impact of modern melting of ice sheets and glaciers on static sea level has been a particular focus of study (Clark and Lingle 1977;Clark and Primus 1987;Conrad and Hager 1997;Mitrovica et al 2001;Plag 2006;Tamisiea et al 2001;Bamber and Riva 2010;Mitrovica et al 2011;Brunnabend et al 2015;Spada and Galassi 2016). This interest is driven, in part, by the expectation that this contribution will become increasingly dominant across the twenty-first century (Church et al 2013;Kopp et al 2014).…”

“…Moreover, the deformational, gravitational, and rotational effects of ice mass flux on static sea level are well understood (Farrell and Clark 1976). Mass flux from each ice sheet and glacier will drive a unique geographical pattern of static sea level change, and these so-called fingerprints (Plag and Jüttner 2001) now play an important role in analyses of modern sea level records (Hay et al 2015;Brunnabend et al 2015;Spada and Galassi 2016) and assessments of regional sea level hazards (Slangen et al 2012).…”

“…Published fingerprints are relatively few in number and are, with few exceptions (Bamber and Riva 2010;Mitrovica et al 2011), generally based on highly simplified geometries of ice mass flux (e.g., a uniform mass loss across the ice sheet, as in Fig. 1) (Clark and Lingle 1977;Clark and Primus 1987;Conrad and Hager 1997;Mitrovica et al 2001;Plag 2006;Brunnabend et al 2015;Spada and Galassi 2016). This simplification limits the incorporation of more realistic icemelt scenarios into regional sea level projections (Sweet et al 2017) and, more generally, the quantitative assessment of the sensitivity of local sea level to mass flux within different sectors of ice sheets and large glaciers systems.…”

Seasonal Variability in Warm-Water Inflow toward Kangerdlugssuaq Fjord

“…A quadrupling of the loss over this period has increased its current sea level rise contribution to 25% of the total (Straneo and Heimbach 2013;Straneo and Cenedese 2015), with a significant sea level fingerprint in remote locations (Brunnabend et al 2015;Rietbroek et al 2016). GIS meltwater impacts the local ocean circulation and may in the future also affect the global ocean circulation through its impact on the Labrador Sea surface salinity, convection, and thereby the Atlantic meridional overturning circulation (Rahmstorf et al 2015;Boning et al 2016).…”