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Quantifications of Ocean Mass Variation and Steric Sea Level Using GRACE and Satellite Altimetry

Chung-Yen Kuo(1), C.K. Shum(2), Y. Tony Song(3) and Yuchan Yi(4)

(1) National Cheng Kung University, No. 1, Ta-Hsueh Road, Tainan 701, Taiwan
(2) Ohio State University, 2070 Neil Avenue, Columbus 43210, United States
(3) Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91109, United States
(4) Ohio State University, 2070 Neil Avenue, columbus 43210, United States


Sea level rise has been widely recognized as a measurable signal as one of the consequences of possible anthropogenic effect of global climate change. The small rate of sea level rise signal, at 1-2 mm/yr during the last century, at present could only be partially explained by a number of competing geophysical processes, each of which is a complex process within the Earth atmosphere-ocean-cryosphere hydrosphere system. The NASA/GFZ Gravity Recovery and Climate Experiment (GRACE) mission is designed to measure small mass changes over a large spatial scale and in the form of time-varying gravity field. Satellite radar altimetry with a cluster of spaceborne instruments measuring sea surface height changes for ~20 years since the launch of GEOSAT in 1984 and the highly successful TOPEX/POSEIDON in 1992, has been widely accepted to be a viable tool for monitoring contemporary and future global sea level changes. The anticipated accuracy of a mean gravity field with a resolution of 150 km or longer and with an accuracy of 1 cm rms in geoid undulations could be measured by GOCE, which would provide an unprecedented accuracy, combining with GRACE and satellite altimetry and in situ measurements of steric sea level (e.g., ARGO), to measure the absolute circulation and sea level variations and separate the steric and the mass variation components. Advances in general global ocean circulation modeling for topography-following, non-Boussinesq model allows one to validate observations, and physics-based interpolation/prediction of sea level and ocean circulations. We will present results using GRACE, satellite altimetry, steric data and the non-Boussinesq ocean model to quantify sea level variations, with a focus in the Southern Ocean, which is traditionally lack of in situ data.


Workshop presentation

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry