Figure 6: Spectral Power Density obtained for different MDT solutions in a 10°x10° box in the Antarctic Circumpolar Current area for the meridional current, between 38°E and 48°E and between 44°S and 54°S.

4.2 Validation

The validation of the CNES-CLS22 MDT is carried out using different approaches. First, this solution is evaluated qualitatively by region (the European Arctic and the Mid Atlantic Bight), then it is evaluated quantitatively with independent drifter data and then with independent height data estimated from T/S profiles.

4.2.1 Qualitative validation

4.2.1.1 The European Arctic
As seen previously, the CNES-CLS22 MDT provides better coverage of the Arctic region and corrects various CNES-CLS18 artifacts. In this section, we take a closer look at the European Arctic region, and in particular the Yermak Plateau area where the Fram Strait branch of the Atlantic Water flow to the Arctic enters the Polar Basin (fig. 7a), and the St. Anna Trough in the northern Kara Sea which is the main gateway for the Barents Sea branch of the Atlantic Water flow to the Polar Basin (e.g., Schauer et al., 2002, Rudels, 2015; Fig. 7d). We are looking at different solutions for these two areas. For the zoom on the Yermak Plateau, the new CNES-CLS22 MDT solution is shown in Fig. 7a with the bathymetric and geographic elements cited in this section, the CNES-CLS18 MDT solution is shown in Fig. 7b and in 7c the DTUUH2022 solution is shown. For the zoom on the St Anna Through, the CNES-CLS22 MDT solution is shown in Fig. 7d with the geographical elements mentioned, the CNES-CLS18 solution is shown in Fig. 7e and the DTUUH2022 solution in Fig. 7f. A first observation is that the DTUUH2022 solution is smoother than the two CNES-CLS solutions on these two zones.