Deployment of the latest generation of BGC-Argo floats

Eight new Argo floats were deployed in the Nordic Seas during a cruise with R/V Johan Hjort, 15 May - 4 June 2023, with Henrik Søiland (IMR) as cruise leader. The cruise track with the locations of the Argo float deployments is shown in Figure 1.

Figure that shows Cruise track and deployment locations of Argo floats

Figure 1. Cruise track and deployment locations of Argo floats. The large dots indicate locations of Argo float deployments with different colors for the different float types (see Table 1).

The deployed Argo floats were of different float types and included 2 Bio (Provor CTS4) and 4 core (Arvor) floats where two of these had oxygen sensor attached. In addition, two of the latest generation of BGC-Argo floats (Provor CTS5) were deployed; one in the Norwegian Basin and one in the Lofoten Basin. These floats have additional a C-ROVER transmissometer (optical sediment trap for sinking particles) and Underwater Vision Profiles (UVP-6), a miniaturised camera, that allow us to quantify the vertical and temporal variability of zooplankton abundances and other relatively large organisms and particles. These floats have also extra battery package (Jumbo).

Table 1. Float types

At each deployment location a CTD-station was taken with water samples for analysis of salinity, nutrients, oxygen (analyzed on board), chlorophyll-a, pH and Particulate Organic Carbon (POC) for comparison with Argo data.

Picture of Deployment of one of the latest generations of BGC-Argo floats
Deployment of one of the latest generations of BGC-Argo floats (Provor CTS5). Photo: Henrik Søiland (IMR).

Recovering of two Argo floats

One BGC-float (WMO 6903574) and one Deep-float (WMO 6903556) were also recovered on the cruise. The BGC-Argo float performed 200 profiles and has been operated for nearly three years while the Deep-float performed 110 cycles over three years.

Picture trah shows Recovery of an Argo float
Recovery of an Argo float. Photo: Henrik Søiland (IMR).

NorArgo status

With the new Argo float deployments, Argo Norway (NorArgo) has at present (29. August 2023) 42 operative Argo floats. These include five BGC-floats, seven Bio-floats, six deep floats, five core floats with oxygen sensor, and 19 core floats. The locations of the Norwegian and other countries operative floats in the Nordic Seas and Barents Sea are shown in figure 3.

Figure that shows perative Argo floats in the Nordic Seas and Barents Sea.

Figure 3. Operative Argo floats in the Nordic Seas and Barents Sea. Red colors: NorArgo floats.