Monday, April 18, 2016 - 4:00pm
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Haller Hall, Geo Museum 102, 24 Oxford St., Cambridge

EPS Colloquium Series

“Weighting Climate Change from Space" with Dr. Isabella Velicogna, University of California, Irvine.

Abstract: In this talk I will present geophysical applications of time-variable gravity from the GRACE satellite mission in ice sheet mass balance and high latitude water cycle. Over ice sheets, GRACE has provided precise measurements of change in mass since 2002 on a monthly basis. The data show that the mass loss has been increasing with time and spreading around Greenland. We find an excellent agreement between GRACE results and estimates from satellite interferometry, altimetry and regional climate models. In Antarctica, the mass loss is more localized but accelerating as well, and we detect large snowfall events in East Antarctica that have been used to evaluate regional atmospheric climate models. The GRACE data remain affected by residual uncertainties in glacial isostatic adjustment, but progress has been made to reduce them and this does not affect the rate of change in mass loss. We have also been able to survey all glaciers and ice caps from outside Greenland and Antarctica using GRACE to get a complete mass budget for land ice. We used GRACE derived mass fluxes from the ice sheets, glaciers and ice caps and land water mass to calculate their contribution to regional sea level variations (or sea level fingerprints, SLF). To evaluate the SLF, we compare them with ocean bottom pressure measurements and for the first time we show that we can detect the SLF signature. We also find an excellent agreement with the sea level variation calculated from satellite altimetry minus Argos floats. In the high arctic, the GRACE data are used to close the water budget and estimate changes in total water storage, which is instrumental for evaluating its impact on ecosystems and precipitation from reanalysis data. We will end the presentation with a discussion of follow-on missions to GRACE for the coming decades.

**Post-talk Reception to follow in Hoffman 4th floor lounge**

Contact Name: 

Sabinna Cappo

Research Areas: 

Harvard University
Center for the Environment

Address: 26 Oxford Street, 4th Floor, Cambridge
Phone: (617) 495-0368

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