Applying area-locked, shallow water Argo floats in Baltic Sea monitoring

ABSTRACT Argo floats have been successfully used for more than 10 years in the world's ocean. The Finnish Meteorological Institute began to develop practices to use Argo floats in the shallow brackish water Baltic Sea in 2011. Since 2012, Argo floats have been in continuous use in the Baltic Sea and are now a part of the Euro–Argo European Research Infrastructure Consortium (ERIC). The floats are kept in the different basins of the Baltic Sea, usually for a year and then recovered and replaced with a new float. The observation cycle is usually a week in monitoring mode, but we have also used shorter intervals up to one day. With proper piloting practices, Argo floats are of great value in monitoring and for research of shallow marginal seas, as they give regular and frequent data around the year, regardless of weather conditions. Operating the floats has matured to a level where we can state that Argo monitoring of the Baltic Sea is an operative reality.