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.