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Abstract:
Sea level rise associated with idealized Greenland and Antarctic ice
sheet melting events is examined using a global coupled ocean sea-ice
model that has a free surface formulation and thus can simulate fast
barotropic motions. The perturbation experiments follow the Coordinated
Ocean-ice Reference Experiment (CORE) version III. All regions of the
global ocean experience a sea level rise within 7-8 days of the
initialization of a polar meltwater input of 0.1 Sv (1 Sv equivalent to
10(6) m(3) s(-1)). The fast adjustment contrasts sharply with the slower
adjustment associated with the smaller steric sea level evolution that
is also connected with melt events. The global mean sea level rises by 9
mm yr(-1) when this forcing is applied either from Greenland or
Antarctica. Nevertheless, horizontal inter-basin gradients in sea level
remain. For climate adaption in low-lying coastal and island regions, it
is critical that the barotropic sea level signal associated with melt
events is taken into consideration, as it leads to a fast sea level rise
from melting ice sheets for the bulk of the global ocean. A linear
relation between sea level rise and global meltwater input is further
supported by experiments in which idealized melting occurs only in a
region east or west of the Antarctic Peninsula, and when melting rates
are varied between 0.01 Sv and 1.0 Sv. The results indicate that in
ocean models that do not explicitly represent the barotropic signal, the
barotropic component of sea level rise can be added off-line to the
simulated steric signal.
