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.

A BGC-Argo Guide: Planning, Deployment, Data Handling and Usage

“…In the Baltic Sea, a permanent presence in the Gotland basin has been maintained by Argo Finland since 2013 using 2 floats interchangeably (Siiriä et al, 2018). The NAOS Mediterranean array has been maintained since 2012 with about a dozen active BGC-Argo floats and a total fleet of 30 BGC-Argo floats.…”

Fishing Gear as a Data Collection Platform: Opportunities to Fill Spatial and Temporal Gaps in Operational Sub-Surface Observation Networks

“…On a global scale, the spatial distributions of fishing activities are an advantage, concentrating potential collection platforms where needed. Shallow shelf seas and near-coastal waters with variable benthic features and high maritime traffic put autonomous platforms and buoys at risk of bumping into the hazardous bottom (Siiriä et al, 2019). The physical irregularity of bathymetric features such as shelf edges disrupt water mass movement, often triggering mixing zones, oceanographic fronts and local upwelling (Cohen and Wright, 1979).…”

“…Argo floats have resulted in a step-change improvement for global sub-surface ocean observation, and therefore, for oceanography on a whole (von Schuckmann et al, 2016). However, operating Argo floats in shelf seas has proved to be difficult and is not widely practiced (Siiriä et al, 2019). The successful deployment of the large scale Argo program, combined with operational ranges of Argo floats, means that there are now more physical subsurface observations of the open ocean than in coastal and shelf sea regions (Killick et al, 2019).…”

A Synthesis of Marine Monitoring Methods With the Potential to Enhance the Status Assessment of the Baltic Sea

“…It frequently surfaces by changing buoyancy due to an oil filled bladder. In general, an Argo Float profiles at 10-day intervals, but intervals can also be programmed to generate, for instance, multiple profiles a day (Roiha et al, 2018;Siiriä et al, 2019). In marine monitoring Argo Floats can be deployed to autonomously obtain high-resolution vertical profiles of the water column to assess eutrophication and hydrographical conditions.…”