Operational Plans

A20 Description of Operations

An oceanographic transect in the Atlantic Ocean, nominally along 52° 20’ W, a repeat of the GO-SHIP Hydrographic Program section A20, is scheduled on R/V T.G. Thompson in March-April 2021. A proposed cruise track is shown in Figure 1. The science portion of the current track closely follows the previous occupation in 2012, except with closer station spacing on the interior portion of the line.

The operations will consist of a series of:

1. Rosette/CTD/LADCP; 2) Six Argo float deployments
2. Eight BGC-Argo float deployments
3. Three RAFOS float deployments

98 stations and 1 test station are planned, with a spacing of approximately 30 nm, except over the shelf and boundary currents at the beginning and end of the lines (stations 1 – 15 and 77 – 98) where spacing will range from ~3 – 13 nm. At every station, full depth Rosette/CTD/LADCP/FLBB/Transmissometer casts will be done. The Rosette will be lowered to approximately 10 m from the bottom. During each station, we will collect up to 36 water samples for measurement of various water properties, such as CO2-related parameters, dissolved CFCs, oxygen, salinity, nutrients, etc. CTD, LADCP, oxygen, fluorometer and backscatter data will be also collected at each station. The collected water samples will be analyzed on board or stored and shipped later to shore (US) for subsequent analysis.

We will monitor and collect data from the standard meteorological sensors (wind speed and direction, air temperature) mounted on the ship’s meteo tower. We will also monitor the ship-mounted underway bathymetry from the multibeam (full swath not required).

For the deployment of the Rosette, chief and co-chief scientists/ODF personnel/students will communicate with the marine technicians/crew for winch operations. At the end of each cast, scientists and technicians will draw water samples from the Rosette Niskin bottles, while the ship is underway.

Several different types of floats will be deployed; 6 WHOI Argo floats, 8 UW biogeochemical (BGC) floats from the biogeochemical Argo project, and 3 WHOI RAFOS floats will be deployed. All floats will be deployed at CTD stations. The Argo and BGC Argo floats will be deployed at the station closest to the desired location (Table 1). The RAFOS floats will all be deployed at the same station, with water depth greater than 4500m and not near a seamount (ideally between stations 17 – 25, with 19 preferred). BGC floats will require slow steaming away from station during deployment. Tests and main preparation of the floats will be done at port, during the mobilization. The co-chief scientist will be charge of the deployment operations and he, or a designated scientist, will assist the marine technician with the deployment procedure from the aft deck of the vessel.

See full Operational Plan here.

A20 Science Team

A22 Description of Operations

An oceanographic transect in the Atlantic Ocean, between 70° W and 65° W, a repeat of the GO-SHIP Hydrographic Program section A22, is scheduled on R/V Thomas G. Thompson between April XX and May XX, 2021. A proposed cruise track is shown in Figure 1. The science portion of the current track closely follows the previous occupation in 2012, except with closer station spacing on the line’s interior portion.

The operations will consist of:

1. 91 Rosette/CTD/LADCP/CHIPODS stations and a test cast during the transit time
2. 9 Argo float deployments, here called Core Argo
3. 4 BGC-Argo float deployments
4. 2 Canadian Arvor floats
5. 1 Deep SOLO float deployment

91 stations and 1 test station are planned, with a spacing of approximately 30 nm, except over the shelf and boundary currents (stations 1-10; 22-27; 32-42; and 77 – 91), where spacing will range from ~2-20 nm. At every station, full depth Rosette/CTD/LADCP/FLBB/Transmissometer/CHIPODS casts will be done. The Rosette will be lowered to approximately 10 m from the bottom. During each station, we will collect up to 36 water samples for measurement of various water properties, such as CO2-related parameters, dissolved CFCs, oxygen, salinity, nutrients, etc. CTD, LADCP, oxygen, fluorometer, and backscatter data will also be collected at each station. For stations outside foreign EEZ with Sargasso presence, we will also collect seaweed samples using a dip net. The collected water samples will be analyzed onboard or stored and shipped later to shore (US) for subsequent analysis.

We will monitor and collect data from the standard meteorological sensors (wind speed and direction, air temperature) mounted on the ship’s meteo tower. We will also monitor the ship-mounted underway bathymetry from the multibeam (full swath not required).

For the deployment of the Rosette, chief and co-chief scientists/ODF personnel/students will communicate with the marine technicians/crew for winch operations. At the end of each cast, scientists and technicians will draw water samples from the Rosette Niskin bottles while the ship is underway.

Several different types of floats will be deployed: 9 WHOI Argo Core floats, 1 WHOI Deep SOLO float, 4 UW biogeochemical (BGC) floats from the biogeochemical Argo project, and 2 Canadian Arvor floats (in the same station) will be deployed. All floats will be deployed at CTD stations, except the first Core Argo that will be deployed in the test station during transit. BGC floats will require slow steaming away from station during deployment. Tests and main preparation of the floats will be done at port during the mobilization. The co-chief scientist will be in charge of the deployment operations, and she, the chief-scientist and/or a CTD watchstander, will assist the marine technician with the deployment procedure from the aft deck of the vessel. 

See full Operational Plan here.

A22 Science Team