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Thermal expansion

by GOHS last modified Dec 29, 2010 03:18 PM



Thermal expansion


It has been possible to quantify thermal expansion's contribution over the 1950-2005 period and compare the values based on 4 sets of global ocean subsurface temperature data published for the last 50 years (Levitus et al., 2000, 2005 and Ishii et al., 2003, 2006). The results indicate that in terms of global average, thermal expansion contributed ~0.4 mm/yr of the 1950-2000 period, namely 25% of the rise observed by tide gauges.

Niveau de la mer b2-fig1

This result indirectly suggests an ocean mass contribution due to freshwater mass releases from continents and ice sheets of the order of 1.4 mm/yr (Lombard et al., 2005 a, b).


Thermal expansion's contribution has also been estimated for the 1993-2003 period, (work led by Alix Lombard in collaboration with CLS), using a new ocean temperature database (the ARMOR base, constructed with in situ hydrographic data from the WOCE, ARGO and other programmes). Thermal expansion over the 1993-2003 period is estimated at approx. 1.5 mm/yr, i.e. roughly 50% of the rate sea level rise measured by altimetry (and equal to 3.3 mm/yr). This constrains the contribution of continental waters and land ice melt to 1.4 mm/yr for both periods (1950-2000 and 1993-2003). This indirect estimate of the contribution of water masses agrees well with the most recent estimates of mountain glaciers and Antarctic and Greenland ice mass loss, of the order of 1.2 mm/yr (see Cazenave and Nerem, 2004, Nerem et al., 2006 and Cazenave, 2007).

Niveau de la mer b2-fig2

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