Inversion of global tide gauge data for present-day ice load changes (scientific paper)

• Main Authors: Plag,Hans-Peter, Juettner,Hans-Ulrich
• Format: Report
• Language: English
• Published: Norwegian Mapping Authority/Institute for Geophysics, University Kiel 2001
• Subjects: Antarctic; Greenland; The Antarctic; Antarc*; Ice Sheet; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2385; http://id.nii.ac.jp/1291/00002385/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2385&item_no=1&attribute_id=18&file_no=1

Trends in relative sea level as recorded by the large number of coastal tide gauges are used to derive new constraints on trends in the Antarctic and Greenland ice sheets on century time scales. Based on the sea-level equation, which describes the spatial pattern of sea-level changes due to changes in the ice masses, for each ice sheet the finger-print function for a constant trend is derived. These finger-print functions are used to determined the best-fit trends from the tide gauge trends. A fit to all tide gauge trends excluding only those with unreasonably large values indicates negative rates of approximately -50mm/yr for the Antarctic ice sheet and -50 to -100mm/yr for the Greenland ice sheet, with the latter strongly depending on the model used to predict the post-glacial signal. However, excluding tide gauge trends from lower latitudes, the fit results in positive trends for both the Antarctic and Greenland ice sheets. This high sensitivity of the inversion to a zonal selection of tide gauges indicates that the tide gauge trends may be contaminated by a latitude-dependent steric effect due to zonal warming of the ocean water.