Summary
In autumn 2005, the GCOS Working Group on SST and Sea Ice (GCOS SST&SI WG) was redefined. The working group had been in existence, but inactive, for some 5 years, however it was concluded that there is a need for its activities. In short, the working group shall stimulate the creation of long-term homogeneous SST and sea ice concentration data sets with quantified uncertainties through intercomparison of several near real-time and historical SST and sea ice analyses. The activities on sea ice were kicked off at the first meeting of an initial core group in Boulder in late March 2006. In the present phase, a crucial activity of the initial group is to oversee the take up of relevant groups and scientists in the sea ice subgroup. Previous long term studies have to some extent been limited by the fact that no error estimates exist for present day ice concentration analyses. Hence, an important short term objective is to promote and develop ice concentration analyses with attached error estimates. In the longer term, the working group shall work to reconcile passive microwave, ice chart and paleo ice analyses to help the formation of consistent and homogeneous long term data sets and a possible extension to sea ice thickness is also envisaged. The data recovery and standardisation activities within ASPeCt are of primary relevance to the activities of the GCOS SST &SI WG. The talk/poster will concentrate particularly on Antarctic conditions in the presentation of working group remit, planned activities and some problems of special concern.