2pm at Nansen (Copernicus, 1st floor).
Talk by Jiping Xie (NERSC).


Sea ice exists between the atmosphere and the ocean and plays a fundamental role in the global energy budget. Among the global warming events in the past three decades, the shrinking and thinning of sea ice is one of the most dramatic changes in the Arctic. Under the surface, the knowledge of sea ice thickness (SIT), long relied on sparse in situ observations with temporally discontinuous, is far from an understanding of its real variabilities since it is rather difficult to monitor from satellites. In recent years, with the developments of satellite technology and coupled data assimilation (DA) approach, the satellite-based SIT has been generally assimilated into the Arctic coupled DA system-TOPAZ4. The current operational Arctic forecast model also benefits from the assimilation of the SIT observations from CS2SMOS in which the SIT measurements consist of SMOS and Cryosat2. In the next upgraded model system-TOPAZ5, the preliminary assimilation tests under the multicategory sea ice set propose new challenges for the coupled DA system such as 1) subscale SIT distribution; 2) adapted localization across different model components; 3) new type of observations like sea-ice age. They become our open questions and need to be treated well soon.