Data Analysis and Modeling of the Amundsen Sea Embayment - Towards an Interdisciplinary Approach in Earth System Science - page 122

Fig. 1 a Distribution of CTD stations in the eastern Amundsen Sea of the cruise ANTXXVI/3 in
2010 with bathymetry, ice shelf, and coastline (gray shade). The 500-m contour is also shown (thin
gray). The lower-left inlet figure shows Antarctica with the enclosed region denoting the location of
the enlarged portion. Solid dots indicate the position of CTD stations and lines marked 1 - 2 are the
sections discussed in this paper. The location of Pine Island Ice Shelf (PIIS) and Pine Island Trough
(PIT) are shown. Letters E and Cmark the submarine glacial troughs located on the eastern and central
Amundsen Sea continental shelf. b Vertical section of potential temperature of Sect. 1 shown by
colors and thick black contours. Surface referenced potential density is indicated by white contours.
The vertical black lines mark the location of CTD pro les with station numbers shown at the top.
Bottom topography is based on RTopo-1 (Timmermann et al. 2010 ). c Same as b but along Sect. 2

3 Modeling of the Amundsen Sea

Several approaches have been conducted to simulate the CDW intrusion onto the
Amundsen Sea continental shelf in regional and global models (Thoma et al. 2008 ;
Timmermann et al. 2009 , 2012 ; Schodlok et al. 2012 ; Assmann et al. 2013 ; Ku-
sahara and Hasumi 2013 ). Although regional models have been successful, global
models have not yet reproduced a realistic CDW

flow onto the continental shelf.
In this study, we analyze the results of the global Finite-Element Sea ice-ice
shelf-Ocean Model (FESOM) and focus on the CDW intrusion onto the Amundsen
Sea continental shelf. Details of this model are summarized in Timmermann et al.
( 2009 , 2012 ). We use a tetrahedral mesh with a horizontal length scale of 50 km
along non-Antarctic coasts, which is re

fl

10 km along the Antarctic coast,
7 km under the larger ice shelves in the Ross and Weddell Seas, and

ned to

*

5 km in the
central Amundsen and Bellingshausen seas. To allow for an adequate representation
of ice shelf cavities, we apply a hybrid vertical-coordinate system with 36 layers
where the top 23 layers are terrain-following in a region along the Antarctic coast
for depth shallower than 2,500 m. The model is forced with daily data from NCEP/
NCAR reanalysis and ERA-interim reanalysis (Kalnay et al. 1996 ; Dee et al. 2011 )
for the period of 1979

*

- 1988. We refer to these two cases as NCEP and ERA.