HR: 10:40h
AN: C32A-02    [Abstracts]
TI: The neoglacial mass balance of the Greenland Ice Sheet inferred from sea level observations: reconciling observations and models over different timescales
AU: * Long, A
EM: A.J.Long@durham.ac.uk
AF: University of Durham, Department of Geography Science Site South Road, Durham, DH1 3LE United Kingdom
AU: Roberts, D
EM: D.H.Roberts@Durham.ac.uk
AF: University of Durham, Department of Geography Science Site South Road, Durham, DH1 3LE United Kingdom
AB: This paper uses relative sea level (RSL) data to infer patterns of Greenland Ice Sheet re-growth during the neoglacial, a period of late Holocene climate cooling that began c. 4.5 ka cal. yr BP and culminated in the Little Ice Age. We argue that there is widespread evidence from Greenland for a switch from early and mid Holocene RSL fall to late Holocene RSL rise. This rise reflects the combined effects of the collapsing forebulge of the Laurentide Ice Sheet and the neoglacial re-growth of the Greenland Ice Sheet. Spatial variations in RSL broadly mirror present-day variations in precipitation and temperature across the ice sheet, that are strongly influenced by Greenland's oceanographic and atmospheric setting. Our analysis suggests that neoglacial ice sheet re-loading was greatest in the relatively warm, high precipitation maritime regime of south Greenland. Less re-loading occurred in the cold polar regime of northeast Greenland. The identification of significant late Holocene RSL rise along much of the east coast of Greenland provides support for recent GPS observations of vertical land motions, but contradicts geophysical model outputs from east Greenland which predict only uplift in east Greenland. Widespread regrowth of the ice sheet suggests that the Greenland Ice Sheet has made a stronger negative contribution to global sea level during the late Holocene than previously thought.
DE: 1800 HYDROLOGY
DE: 1200 GEODESY AND GRAVITY
DE: 1600 GLOBAL CHANGE (New category)
DE: 1635 Oceans (4203)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting