Assimilation of Expedition Observation Data on Water Temperature and Salinity in the Region of Drake Passage

Results of numerical experiments on the assimilation of in situ temperature and salinity profiles observed in the region of Drake Passage (the South Atlantic) during the expedition of Shirshov Institute of Oceanology of Russian Academy of Sciences (RAS) in the autumn of 2011 into the INMOM model developed by Marchuk Institute of Numerical Mathematics of RAS are considered. The previously developed method of assimilation presented in several publications is used. As a result of some experiments, it has been shown that the structure of the anticyclonic circulation associated with the Brazil-Malvinas Confluence in the area of the Argentine Basin has been mostly affected by the expedition data assimilation. Assimilated fields of ocean temperature on the surface and at various horizons show better agreement with reanalysis data than corresponding fields without assimilation. It is also demonstrated that the influence of assimilation spreads much further beyond the local area of observations and leads to changing all calculated characteristics (not only observed ones).