HR: 16:15h
AN: G44A-02 INVITED    [Abstracts]
TI: Regional variability of sea level trends
AU: * Cazenave, A
EM: anny.cazenave@cnes.fr
AF: LEGOS, 18 avenue Edouard Belin, TOULOUSE, 31400, France
AU: Lombard, A
EM: alix.lombard@legos.obs-mip.fr
AF: LEGOS, 18 avenue Edouard Belin, TOULOUSE, 31400, France
AU: Llovel, W
EM: william.llovel@legos.obs-mip.fr
AF: LEGOS, 18 avenue Edouard Belin, TOULOUSE, 31400, France
AU: Abarca del Rio, R
EM: rodrigo_abarca_del_rio@yahoo.fr
AF: Universidad de Conception Universidad de Conception, Barillo Universitario S/N, CONCEPTION, 160, Chile
AB: Satellite altimetry has allowed precise mapping of the geographical variability of the rates of sea level change and showed that sea level is far from rising uniformely. In some regions, rates are up several times the global mean rise, while in other regions sea level is falling. Like observed sea level trends, observed and model-based ocean thermal expansion trends are not spatially uniform and at least for the recent years, closely resemble the sea level trends patterns. Such a result suggests that non uniform thermal expansion (i.e. non uniform ocean heat content) is the main cause of observed sea level regional variability. However, salinity changes are not negligible at regional scale. In many oceanic regions, temperature and salinity contributions compensate each other and it is indeed the net effect that is responsible of the patterns seen in altimetry-derived sea level trend maps. Self- gravitational effects of present-day meltwater over the oceans also contribute to the spatial trend patterns. The spatial patterns observed in the rates of thermal expansion seem to be subject to high interannual/decadal variability related to ENSO, PDO and NAO variability. Is this also true for sea level, considering that temperature and salinity partially compensate at regional scale? In this presentation, we discuss the stationarity of the spatial trend patterns over the past few decades in sea level, thermal expansion and halosteric effects using observations, global ocean circulation models outputs and sea level reconstructions. The question we intend to address is : are the altimetry-derived spatial patterns transient structures or do they reflect long-term regional trends? This is an important topic for identifying the most vulnerable regions affected by sea level rise.
DE: 1222 Ocean monitoring with geodetic techniques (1225, 1641, 3010, 4532, 4556, 4560, 6959)
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
DE: 1622 Earth system modeling (1225)
DE: 1641 Sea level change (1222, 1225, 4556)
DE: 4556 Sea level: variations and mean (1222, 1225, 1641)
SC: Geodesy [G]
MN: 2007 Fall Meeting