RRS Discovery DY174
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS Discovery (74EQ) |
| Cruise identifier | DY174 |
| Cruise period | 2024-03-28 — 2024-04-03 |
| Status | Completed |
| Port of departure | Santa Cruz de Tenerife, Spain |
| Port of return | Santa Cruz de Tenerife, Spain |
| Purpose | Research |
| Objectives | The primary objective of the cruise was to service the eastern section of the RAPID 26N array of moorings that is deployed across the subtropical Atlantic to measure the variability of the Atlantic Meridional Overturning Circulation (AMOC). The main measurements required are of temperature, salinity, ocean current speed and bottom pressure.
In additional the cruise had a number of additional objectives: - To improve understanding of the meridional transport of carbon by the ocean additional instruments were recovered from moorings to measure Oxygen, pH, phosphate, Nitrate, total Alkalinity and pCO2 sensors. - To calibrate the moored instruments a number of CTD profiles were made measuring temperature, salinity and oxygen. Water samples were taken and analysed for salinity and oxygen. Some samples will later be analysed for dissolved inorganic carbon, total alkalinity, inorganic nutrients and organic nitrogen. - Two Argo floats were deployed. These are a part of the international Argo program (http://www.argo.net). |
| Chief scientist | Ben I Moat (National Oceanography Centre, Southampton) |
| Project | Monitoring the Meridional Overturning Circulation at 26.5 North |
| Coordinating body | National Oceanography Centre (NOC) |
| Cruise report |  (4.74 MB) |
| Ocean/sea areas | |
| General | North East Atlantic Ocean (limit 40W) |
| Measurements | |
| Physical oceanography | |
| Surface measurements underway (T,S) | Quantity: activity duration in days = 6 Description: Underway measurement were made of meteorological variables (wind speed and direction, air temperature and humidity, surface pressure and irradiance); surface (5m) temperature and salinity; subsurface currents from 150kHz and 75 kHz ADCPs; bathymetry from single and multi-beam echo sounders. |
| CTD stations | Quantity: number of stations = 12 Description: CTD stations, vertical profiles of conductivity, temperature, pressure and oxygen. Samples were taken for calibration of salinity and oxygen |
| Current profiler (eg ADCP) | Quantity: activity duration in days = 6 Description: Underway measurement were made of meteorological variables (wind speed and direction, air temperature and humidity, surface pressure and irradiance); surface (5m) temperature and salinity; subsurface currents from 150kHz and 75 kHz ADCPs; bathymetry from single and multi-beam echo sounders. |
| Chemical oceanography | |
| Oxygen | Quantity: number of stations = 12 Description: CTD stations, vertical profiles of conductivity, temperature, pressure and oxygen. Samples were taken for calibration of salinity and oxygen |
| Carbon dioxide | Quantity: number of stations = 5 Description: On selected CTD stations samples were taken and stored for later analysis of dissolved inorganic carbon, and total alkalinity |
| Phosphate | Quantity: number of stations = 4 Description: On selected CTD stations samples were taken and stored for later analysis of inorganic nutrients and organic nitrogen |
| Total - P | Quantity: number of stations = 4 Description: On selected CTD stations samples were taken and stored for later analysis of inorganic nutrients and organic nitrogen |
| Nitrate | Quantity: number of stations = 4 Description: On selected CTD stations samples were taken and stored for later analysis of inorganic nutrients and organic nitrogen |
| Nitrite | Quantity: number of stations = 4 Description: On selected CTD stations samples were taken and stored for later analysis of inorganic nutrients and organic nitrogen |
| Silicate | Quantity: number of stations = 4 Description: On selected CTD stations samples were taken and stored for later analysis of inorganic nutrients and organic nitrogen |
| pH | Quantity: number of stations = 5 Description: On selected CTD stations samples were taken and stored for later analysis of dissolved inorganic carbon, and total alkalinity |
| Meteorology | |
| Incident radiation | Quantity: activity duration in days = 6 Description: Underway measurement were made of meteorological variables (wind speed and direction, air temperature and humidity, surface pressure and irradiance); surface (5m) temperature and salinity; subsurface currents from 150kHz and 75 kHz ADCPs; bathymetry from single and multi-beam echo sounders. |
| Routine standard measurements | Quantity: activity duration in days = 6 Description: Underway measurement were made of meteorological variables (wind speed and direction, air temperature and humidity, surface pressure and irradiance); surface (5m) temperature and salinity; subsurface currents from 150kHz and 75 kHz ADCPs; bathymetry from single and multi-beam echo sounders. |
| Geology and geophysics | |
| Single-beam echosounding | Quantity: activity duration in days = 6 Description: Underway measurement were made of meteorological variables (wind speed and direction, air temperature and humidity, surface pressure and irradiance); surface (5m) temperature and salinity; subsurface currents from 150kHz and 75 kHz ADCPs; bathymetry from single and multi-beam echo sounders. |
| Multi-beam echosounding | Quantity: activity duration in days = 6 Description: Underway measurement were made of meteorological variables (wind speed and direction, air temperature and humidity, surface pressure and irradiance); surface (5m) temperature and salinity; subsurface currents from 150kHz and 75 kHz ADCPs; bathymetry from single and multi-beam echo sounders. |
| Moorings, landers, buoys | |
| Physical oceanography | |
| CTD stations | 27° 10' 47" N 16° 47' 42" W — Argo autonomous profiling float #9600, 0-2000m deployed |
| CTD stations | 27° 13' 36" N 15° 24' 53" W — Argo autonomous profiling float #9601, 0-2000m deployed |
| Subsurface temperature and salinity measurements | 27° 48' 29" N 13° 44' 48" W — EBH3: 20 CTD, 7 Oxygen, 4 CM, 2 pH, 2 TA, 3 Nitrate, 1 Phosphate, 50m-1400m recovered |
| Subsurface temperature and salinity measurements | 27° 45' 0" N 13° 49' 59" W — EBH3B: 13 CTD 50-1500 m deployed |
| Subsurface temperature and salinity measurements | 27° 36' 53" N 14° 12' 42" W — EBH2: 3 CTD, 1 Oxygen, 1600m-2000m deployed |
| Subsurface temperature and salinity measurements | 27° 36' 53" N 14° 12' 42" W — EBH1: 2 CTD, 1 Oxygen, 1600m-2000m deployed |
| Subsurface temperature and salinity measurements | 27° 36' 53" N 14° 12' 42" W — EBH1: 2 CTD, 2 Oxygen,1 TA,1 Ph 1600m-2000m recovered |
| Subsurface temperature and salinity measurements | 27° 48' 29" N 13° 44' 48" W — EBH3: 13 CTD, 4 Oxygen, 4 CM deployed |
| Subsurface temperature and salinity measurements | 27° 36' 53" N 14° 12' 42" W — EBH2: 4 CTD, 1 Oxygen, 1600m-2000m recovered |
| Current meters | 27° 48' 29" N 13° 44' 48" W — EBH3: 20 CTD, 7 Oxygen, 4 CM, 2 pH, 2 TA, 3 Nitrate, 1 Phosphate, 50m-1400m recovered |
| Current meters | 27° 36' 53" N 14° 12' 42" W — EBH2: 3 CTD, 1 Oxygen, 1600m-2000m deployed |
| Current meters | 27° 36' 53" N 14° 12' 42" W — EBH2: 4 CTD, 1 Oxygen, 1600m-2000m recovered |
| Current meters | 27° 36' 53" N 14° 12' 42" W — EBH1: 2 CTD, 1 Oxygen, 1600m-2000m deployed |
| Current meters | 27° 36' 53" N 14° 12' 42" W — EBH1: 2 CTD, 2 Oxygen,1 TA,1 Ph 1600m-2000m recovered |
| Current meters | 27° 48' 29" N 13° 44' 48" W — EBH3: 13 CTD, 4 Oxygen, 4 CM deployed |
| Sea level (inc. bot. press., inverted echosounder) | 27° 12' 11" N 15° 25' 18" W — EBH1L14: 2 bottom pressure recorders, 3000 m recovered |
| Sea level (inc. bot. press., inverted echosounder) | 27° 12' 11" N 15° 25' 18" W — EBH1L16: 2 bottom pressure recorders, 3000 m deployed |
| Sea level (inc. bot. press., inverted echosounder) | 27° 47' 53" N 13° 44' 48" W — EBH3L: 2 bottom pressure recorders, 1400 m recovered and deployed |
| Chemical oceanography | |
| Oxygen | 27° 48' 29" N 13° 44' 48" W — EBH3: 20 CTD, 7 Oxygen, 4 CM, 2 pH, 2 TA, 3 Nitrate, 1 Phosphate, 50m-1400m recovered |
| Oxygen | 27° 48' 29" N 13° 44' 48" W — EBH3: 13 CTD, 4 Oxygen, 4 CM deployed |
| Phosphate | 27° 48' 29" N 13° 44' 48" W — EBH3: 20 CTD, 7 Oxygen, 4 CM, 2 pH, 2 TA, 3 Nitrate, 1 Phosphate, 50m-1400m recovered |
| Nitrate | 27° 48' 29" N 13° 44' 48" W — EBH3: 20 CTD, 7 Oxygen, 4 CM, 2 pH, 2 TA, 3 Nitrate, 1 Phosphate, 50m-1400m recovered |
| Alkalinity | 27° 36' 53" N 14° 12' 42" W — EBH1: 2 CTD, 2 Oxygen,1 TA,1 Ph 1600m-2000m recovered |
| Alkalinity | 27° 48' 29" N 13° 44' 48" W — EBH3: 20 CTD, 7 Oxygen, 4 CM, 2 pH, 2 TA, 3 Nitrate, 1 Phosphate, 50m-1400m recovered |
| pH | 27° 48' 29" N 13° 44' 48" W — EBH3: 20 CTD, 7 Oxygen, 4 CM, 2 pH, 2 TA, 3 Nitrate, 1 Phosphate, 50m-1400m recovered |
| pH | 27° 36' 53" N 14° 12' 42" W — EBH1: 2 CTD, 2 Oxygen,1 TA,1 Ph 1600m-2000m recovered |
| Data held at BODC | |
| Discrete samples | |
| 12 CTD frame plus rosette sampler | |
| 6 Instrument mooring | |
| 20 Sample taken from ship's non-toxic supply |
