Tide gauge-based sea level variations since 1950 along the Norwegian and Russian coasts of the Arctic Ocean: Contribution of the steric and mass components

Olivier Henry (1) , Pierre Prandi (2) , W. Llovel (3) , Anny Cazenave (1) , Svetlana Jevrejeva (4) , Detlef Stammer (5) , Benoit Meyssignac (1) , Nikolay V. Koldunov (6)

1 LEGOS - Laboratoire d'études en Géophysique et océanographie spatiales
2 CLS - Collecte Localisation Satellites [Toulouse]
3 JPL - Jet Propulsion Laboratory
4 NOC - National Oceanography Centre [Southampton]
5 Institute of Marine Sciences
6 Institute of Marine Sciences

We investigate sea level change and variability in part of the Arctic region over the 1950-2009 period. Analysis of 62 long tide gauge records along the Norwegian and Russian coastlines shows that coastal mean sea level in these two areas was almost stable until about 1980 but since then displayed a clear increasing trend, following fluctuations of Arctic Oscillation. After the mid-to-late 1990s the co-fluctuation with the AO disappears, to achieve an increasing trend of ~4 mm/yr since 1995. Using in situ ocean temperature and salinity data from three different databases, we estimated the thermosteric, halosteric and steric sea level since 1970 in the North Atlantic and Nordic Seas region (incomplete data coverage prevented us to analyze steric data along the Russian coast). We note a strong anti-correlation between the thermosteric and halosteric components both in terms of spatial trends and regionally averaged time series. The latter show a strong change as of ~1995 that indicates increase in temperature and salinity, confirmed by the Empirical Orthogonal Function decomposition. Regionally steric data are compared to altimetry-based sea level over 1993-2009. Spatial trend patterns of altimetry-based sea level are largely explained by steric patterns, but residual spatial trends suggest that other factors contribute. Focusing on Norwegian tide gauges, we compare observed coastal mean sea level with the steric sea level and the ocean mass component estimated with GRACE gravimetry data (since 2003) and conclude that the mass component partly explains the sustained sea level rise (of ~4 mm/yr) over the altimetry era.

Domaines: Océan, Atmosphère

Olivier Henry, Pierre Prandi, W. Llovel, Anny Cazenave, Svetlana Jevrejeva, et al.. Tide gauge-based sea level variations since 1950 along the Norwegian and Russian coasts of the Arctic Ocean: Contribution of the steric and mass components. Journal of Geophysical Research, 2012, 117, pp.C06023. ⟨10.1029/2011JC007706⟩. ⟨hal-00784588⟩