Data Analysis and Modeling of the Amundsen Sea Embayment - Towards an Interdisciplinary Approach in Earth System Science - page 123

Fig. 2 Modeled bottom potential temperature in the Amundsen Sea for January 1984 in the NCEP
case (AG Abbot Glacier, CG Cosgrove Glacier, PIIS Pine Island Ice Shelf, TWG Thwaites Glacier,
CRG Crosson Glacier, DG Doston Glacier, Getz Getz Glacier)

Fig. 3 Time series of PIIS ice front bottom potential temperature with NCEP reanalysis (red) and
ERA-interim (blue) forcings

In the NCEP case as shown by Timmermann et al. ( 2012 ), the Amundsen Sea
remains cold throughout this model run, and potential temperature at the bottom
becomes nearly equal to 4 years of model simulation (Fig. 2 ), while

observations show a watermass warmer than 1

1.8 ° C after 3

− -

C at the bottom near the PIIS ice
front Sect. 1 . Timmermann et al. ( 2012 ) indicate that the large difference is caused
by a cold bias in NCEP reanalysis winter temperature, as demonstrated by Assmann
et al. ( 2005 ). In the ERA case, however, CDW temperature at the PIIS ice front
remains cold and no signi

°

cant change can be seen compared to the NCEP case
(Fig. 3 ). This indicates that the forcing is not the only reason for the dif

culties in

reproducing CDW intrusion onto the Amundsen Sea continental shelf.

4 Discussion and Outlook

In this paper, we show the data from hydrographic observations in 2010 (RV
Polarstern cruise, ANTXXVI/3) and discuss the two FESOM simulations with
different atmospheric forcing. As shown by previous studies, CDW intrudes onto