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Cryospheric and Hydrologic Contributions to Global Sea Level Change. M. Tamisiea Proudman Oceanographic Laboratory R. Steven Nerem University of Colorado. AGU Meeting of the Americas, August 8-11, 2010. Measurements of Sea Level Change. G RAVITY. Global Mean Sea Level.
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Cryospheric and Hydrologic Contributionsto Global Sea Level Change M. Tamisiea Proudman Oceanographic Laboratory R. Steven Nerem University of Colorado AGU Meeting of the Americas, August 8-11, 2010
Measurements of Sea Level Change GRAVITY
Global Mean Sea Level Trend = 3.3 mm/year
Hydrology Model vs GRACE [Llovel et al., 2010]
Hydrology Model vs Altimeter GMSL [Llovel et al., 2010]
Hydrology Model vs Tide Gauge GMSL [Llovel et al., 2010]
GRACE Secular Trends (2002-2009) GIA Model Removed [Wahr, 2009]
Greenland Ice Mass Changes from GRACE April, 2002 – June, 2010 Total Greenland ice volume Rate of Ice mass change: All Greenland: -239 Gton/yr South Greenland: -162 Gton/yr North Greenland: -77 Gton/yr (1 Gton = 1 km3 of water) -239 Gton/yr = 0.66 mm/yr sea level rise [Wahr, 2010]
Antarctica Ice Mass Variations from GRACE Total Antarctic ice mass (noisy because of atmospheric pressure errors) April, 2002 – June, 2010 Rate of ice mass change: All Antarctica: -143 Gton/yr West Antarctica: -155 Gton/yr East Antarctica: +15 Gton/yr Uncertainty of GIA correction: All Antarctica: ± 80 Gton/yr West Antarctica: ± 20 Gton/yr East Antarctica: ± 55 Gton/yr -143 Gton/yr = 0.40 mm/yr sea level rise [Wahr, 2010]
Alaskan Glaciers from GRACE Rate of mass change between April, 2002 and May, 2010 . Rate of mass change: -55 Gton/yr = 0.15 mm/yr sea level rise [Wahr, 2010]
Summary of GRACE Ice GMSL Contributions GRACE provides mass loss estimates for entire ice sheets. Between April 2002 and May/June 2010: Greenland lost ice at a rate of 239 Gton/yr. Antarctica lost ice at a rate of 143 Gton/yr. Alaskan glaciers lost ice at a rate of 55 Gton/yr. Total: 437 Gt/yr, equivalent to 1.2 mm/yr sea level rise.
Current Sea Level Budget Thermal Expansion: ~ 1.1 mm/year + Mountain Glaciers: ~ 1.2 mm/year + Greenland Ice Melt: ~ 0.6 mm/year + Antarctic Ice Melt: ~ 0.4 mm/year Land Water Storage: ? = Total: ~ 3.3 mm/year