HR: 16:30h
AN: G34A-03    [Abstracts]
TI: Contribution of Thermal Expansion to 1993-2003 Sea Level Rise
AU: * Lombard, A
EM: lombard@notos.cst.cnes.fr
AF: LEGOS-CNES, 18 avenue Edouard belin, Toulouse, Cedex 9, 31401 France
AU: Cazenave, A
EM: anny.cazenave@cnes.fr
AF: LEGOS-CNES, 18 avenue Edouard belin, Toulouse, Cedex 9, 31401 France
AU: Le Traon, P
EM: pierre.yves.le.traon@ifremer.fr
AF: IFREMER, Centre de Brest, Plouzane, 29280 France
AB: Several estimates of the thermal expansion contribution to the rate of sea level rise observed by satellite altimetry over 1993-2003 (of 3.1 +/- 0.4 mm/yr) have been proposed recently. Two estimates are based on recently updated global 1x1 degree gridded ocean temperature data sets (Levitus et al., 2005; Ishii et al., 2005). Two other estimates are based on a combination of in situ hydrographic profiles and satellite altimetry data (Willis et al., 2004; this study). We have estimated the steric sea level for 1993-2003, using the ARMOR (Multivariate Analysis of the Mercator Observation) developed at CLS (Toulouse, France). ARMOR is a combination -based on optimal interpolation- of about 1 000 000 in situ hydrographic (temperature and salinity) profiles available from different sources with high-resolution sea surface heights from Topex/Poseidon and ERS altimetry, plus sea surface temperature data. The contribution of thermal expansion to 1993-2003 sea level rise based on the Levitus and Ishii data is on the order of 1.2 mm/yr, while the Willis estimate and this study give values of 1.6 and 1.8 mm/yr respectively. We investigate the possible causes of discrepancy between the two sets of results, which is much larger than uncertainties associated with individual results. The main difference between the two sets of thermal expansion estimates is the use of altimetry data in the second set (Willis and this study) to complement the very sparse hydrographic coverage of the southern oceans. The residual maps (altimetry-based sea level trends minus thermal expansion) show much less regional signal with the second set of data than with the first one. The residual maps are compared to regional sea level trend maps predicted by geodetic models of isostatic adjustment of ice melt water flux as well as by ocean models investigating the regional response of sea level to ice sheet melting. Implication for the land ice melting contribution to last decade sea level change is also discussed.
DE: 1640 Remote sensing (1855)
DE: 4275 Remote sensing and electromagnetic processes (0689, 2487, 3285, 4455, 6934)
DE: 4556 Sea level: variations and mean (1222, 1225, 1641)
DE: 4594 Instruments and techniques
SC: Geodesy [G]
MN: Fall Meeting 2005