Glacial isostatic contributions to present day sea level change around Greenland

• Main Author: Fleming, Kevin
• Format: Article in Journal/Newspaper
• Language: English
• Published: GFZ, Helmholtz-Zentrum 2005
• Subjects: ddc:551; Greenland; Qaqortoq; Ice Sheet
• Online Access: http://hdl.handle.net/11858/00-1735-0000-0001-32CD-E; https://doi.org/10.23689/fidgeo-572

Present-day sea-level change around Greenland is examined by assessing the roleplayed by glacial-isostatic adjustment (GIA). We consider the contributions from: (1) the ongoing GIA due to changes in the extent and thickness of the Greenland Ice Sheet (GIS) following the Last Glacial Maximum (LGM), (2) the equivalent signal associated with the continental ice masses located outside of Greenland, and (3) present-day changes in the GIS. Changes in the GIS arising from the last glacial-interglacial transition generally result in falling sea level today. The contribution from ice-load changes outside of Greenland causes rising sea level, owing to Greenland's location on the collapsing forebulge that surrounds the former North American ice sheets. Combining predictions of these contributions gives results showing rising sea level in the southwest and falling sea level in the north and east. However, this is strongly dependent upon the neoglacial part of the GIS's history. The present-day behaviour of the GIS is predicted to cause falling sea level with rates of several mm yr?1 around areas experiencing the larger ice-load changes. The available tide-gauge data are considered unusable by the standards of many workers. Nevertheless, we compare rates of local sea-level change inferred from this type of data with our predictions. In Southern Greenland, where the tide-gauge stations are located, sea level is predicted to be rising at a rate of 4 to 5 mm yr?1. Our predictions match most of the rates obtained from the tide-gauge time series, with the exception of Qaqortoq where the inferred rates may also reect additional oceanic and meteorological effects. Similarly, our predictions are consistent with GPS observations, with again the exception of Qaqortoq. report