HR: 0800h
AN: G51A-0144    [Abstracts]
TI: Observational evidence for volcanic impact on sea level and the global water cycle
AU: * Grinsted, A
EM: ag@glaciology.net
AF: Arctic Centre, Univerity of Lapland, Box 122, Rovaniemi, 96101, Finland
AU: Moore, J C
EM: jmoore@ulapland.fi
AF: Arctic Centre, Univerity of Lapland, Box 122, Rovaniemi, 96101, Finland
AU: Moore, J C
EM: jmoore@ulapland.fi
AF: Division of Geophysics, University of Oulu, Fysikaalisten tieteiden laitos PL 3000, Oulun yliopisto, 90014, Finland
AU: Jevrejeva, S
EM: sveta@pol.ac.uk
AF: Proudman Oceanographic Laboratory, Joseph Proudman building 6 Brownlow Street, Liverpool, L3 5DA, United Kingdom
AB: It has previously been noted that there are drops in global sea level (GSL) following some major volcanic eruptions. However, observational evidence has not been convincing as there is substantial variability in the global sea level record on periods similar to those at which we expect volcanoes to have an impact. To quantify the impact of volcanic eruptions we average monthly GSL data from 830 tide gauge records around 5 major volcanic eruptions. Surprisingly, we find that the initial response to a volcanic eruption is a significant rise in sea level of 9 ± 3 mm in the first year after the eruption. This is followed by a drop of 7 ± 3 mm in the period 2-3 years after the eruption relative to pre-eruption sea level. These results are statistically robust and no particular volcanic eruption or ocean region dominates the signature we find. Neither the drop nor especially the rise in GSL can be explained by models of lower oceanic heat content. We suggest that the mechanism is a transient disturbance of the water cycle with a delayed response of land river runoff relative to ocean evaporation and global precipitation that affects global sea level. The volcanic impact on the water cycle and sea levels is comparable in magnitude to that of a large El Niņo-La Niņa cycle, amounting to about 5% of global land precipitation.
DE: 1641 Sea level change (1222, 1225, 4556)
DE: 1655 Water cycles (1836)
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 8408 Volcano/climate interactions (1605, 3309)
DE: 8409 Atmospheric effects (0370)
SC: Geodesy [G]
MN: 2007 Fall Meeting