j. n. stroh, gleb panteleev, Thomas Weingartner

The Chukchi Sea (CS) is the gateway to the Arctic Ocean (AO) for Pacific waters entering from Bering Strait (BS) and also a potential location for future offshore oil extraction. Since 2010, regional CS data has become more plentiful with acoustic Doppler current profilers (ADCP) moored throughout the northwestern portion of the shelf along with coastal high-frequency radar (HFR) surface current monitoring during the ice-free summer season.  This work develops a data assimilation system (DAS) for these observations which applies an asynchronous variational ensemble filter to a Regional Ocean Modeling System (ROMS) CS domain.  Two configurations of the DAS applied during August--November 2012 are tested and compared with observations from several sources, including unassimilated external data. The tested DAS configurations performed when assimilating surface as a full timeseries of observations rather than as forecast-interval means. The resulting system could be used for future operational forecast refinement in the region well suited for application to surface monitoring and forecast for regional oil spill mitigation.
Failures of background model which limit further analysis are discussed in appended material.