Data Assimilation

Data assimilation is a method used in numerical modeling to assure that model results are close to observations. By using a data assimilation system, we can obtain “analyzed fields”, which are a set of ocean and sea ice variables optimally combining observations and a model. The analyzed fields are applied for a variety of ocean and sea ice studies in the Arctic Ocean, and also provide initial conditions for future projection experiments (e.g., sea ice outlook).We have been developed 4 dimensional variational (4DVar) data assimilation systems (4DVar with an adjoint method and with a genetic algorithm) and apply the systems as a tool to synthesize various observational activities and the coupled ocean-sea ice model NAOSIM (North Atlantic/Arctic Ocean Sea Ice Model) developed at the Alfred Wegener Institute.

Temperature and salinity measurement by ARGO-profiler (www.coriolis.eu.org).
Temperature and salinity measurement by ARGO-profiler (www.coriolis.eu.org)
Temprerature and salinity measurement by RV Polarstern
Temprerature and salinity measurement by RV Polarstern (Photo: M. Hoppmann, AWI)
Sea ice motion vectors deduced from satellite-borne sensors (EUMETSAT Ocean and Sea Ice SAF: www.osisaf.org)
Sea ice motion vectors deduced from satellite-borne sensors (EUMETSAT Ocean and Sea Ice SAF: www.osisaf.org)