Linguistic Naturalism and Natural Style. From Varro and Cicero to Dionysius of Halicarnassus

NWO276-30-009Classics and Classical Civilizatio

Using sea-level data to constrain a finite-element primitive-equation ocean model with a local SEIK filter

Inspired by the pioneering work of Christian Le Provost on finiteelement ocean modeling a new ocean circulation model was developedover the last few years. It applies a surface triangulation and finiteelements for an accurate description of coasts and bathymetry and theirsteering effect on the ocean circulation. A novel feature is the meshdesign which allows a vertical structure in geopotential (z)coordinates without loss of flexibility and avoids pressure gradienterrors everywhere except for the lowest layer of abyssal ocean. Themodel is combined with sea level measurements and data assimilation,another major research topic of Christian Le Provost. We apply the SEIKfilter which was developed in Grenoble while Christian was teachingthere. The addition of a local analysis scheme improves the filterperformance first of all in its variance estimates but also in its meansolution

Steric height variability in the northern Atlantic on seasonal and interannual scales

Steric height (SH) variability computed from Argo profiling buoys data for the North Atlantic and period 1999–2006 is analyzed and compared to the variability computed from the satellite altimetry data. It is demonstrated that although the contribution from halosteric contraction is smaller than that from the thermal expansion, it is not negligible in wide areas in the North Atlantic and cannot be discarded (the regression of trends in full steric and thermosteric heights is 0.73). It is found that the SH variability is not really sensitive to increasing the reference level from 1000 to 1500 m. Differences in trend reach several mm/year locally, which is estimated to be below sampling errors (about 1.4 mm/year). The SH trends are between ±1 cm/year locally. The comparison of SH and altimetric height variability shows qualitative agreement of both for the amplitude of the annual harmonics and trend but reveals significant local differences which cannot be explained by bottom pressure variability. The main modes of variability seen in yearly mean patterns of SH and satellite altimetry are also different. It is suggested that sampling/interpolation errors are still too high to reveal a balance between the SH and altimetric height variability at the local level. <br/