Cruise inventory

RRS Discovery D311

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Discovery (74E3)
Cruise identifierD311
Cruise period2006-09-09 — 2006-10-05
StatusCompleted
Port of departureReykjavík, Iceland
Port of returnReykjavík, Iceland
PurposeResearch
ObjectivesThe objective of the Discovery cruise D311 was to study different aspects of the Denmark Strait overflow.

The first part of the cruise concentrated on examining the water masses at the sill and the upstream conditions in the East Greenland Current and in the Iceland Sea. Two pathways of overflow water have been discovered north of the Denmark Strait. One flows along the Greenland continental slope and involves waters from the Arctic Ocean, Fram Strait and the Greenland Sea. The other runs on the northwestern Iceland shelf and apparently carries the densest overflow water. The origin of this water mass is not yet determined. Does it derive from the Iceland Sea or does it come from farther north? To resolve this question the water mass characteristics in the East Greenland Current and in the Iceland Sea will be examined by CTD observations and water sampling, involving CFCs, H3, He3, O2, O18. In addition, attempts to recover moorings with ROV have been made. The first leg ended in Reykjavik, where exchange of scientific personnel took place.

After the exchange Discovery continued to the Greenland slope, where the VEINS and ASOF CTD sections were taken and the mooring array at Angmassalik recovered and redeployed. The purpose of these sections south of the sill in the Denmark Strait is to study the evolution, strength and variability of the overflow plume - how the different water masses from north of the sill mix on their way to the south, and how much and by what mechanisms ambient water is entrained into the overflow plume. To study these processes the CTD observations and the water sampling were complemented by turbulence measurements using a freefalling CTD and current meter probe.
Chief scientistDetlef Quadfasel (University of Hamburg Oceanography Institute)
ProjectASOF
Cruise reportRRS Discovery D311 cruise report d311.pdf — access key 'C' (13.95 MB) 
Ocean/sea areas 
GeneralNorth Atlantic Ocean
SpecificNorth Atlantic Ocean, Denmark Strait
Track chartsRRS Discovery D311 cruise track — d311trk.pdf (00 MB) 
Measurements 
Physical oceanography 
Surface measurements underway (T,S)Quantity: activity duration in days = 25
Description: SEABIRD - Thermosalinograph
Water bottle stationsQuantity: number of stations = 88
Description: different numbers of salinity- and oxygen (H21) - samples for calibration
CTD stationsQuantity: number of stations = 88
Description: SEABIRD CTD+ROSETTE
CTD stationsQuantity: number of stations = 9
Description: Microstructure - CTD (SEABIRD)
Current profiler (eg ADCP)Quantity: number of stations = 50
Description: LADCP - on CTD+ROSETTE
Current profiler (eg ADCP)Quantity: activity duration in days = 25
Description: RDI - Ship ADCP
Chemical oceanography 
Other chemical oceanographic measurementsQuantity: number of stations = 37
Description: CFC, He, Tritium, O18
Meteorology 
Routine standard measurementsQuantity: activity duration in days = 25
Description: Routine standard measurements
Moorings, landers, buoys 
Physical oceanography 
Current meters63° 0' 59" N  40° 31' 59" W — ADCP recovery 23.09.2006
Current meters63° 21' 59" N  36° 3' 59" W — G1 deployed 26.09.2006
Current meters63° 16' 59" N  35° 52' 59" W — UK2 deployed 26.09.2006
Current meters63° 16' 59" N  35° 51' 59" W — UK2-05 recovery 22.09.2006
Current meters63° 28' 59" N  36° 17' 59" W — UK1-05 recovery 22.09.2006
Current meters63° 28' 59" N  36° 17' 59" W — UK1 deployed 26.09.2006
Current meters63° 34' 59" N  36° 39' 59" W — F12 deployed 26.09.2006
Current meters63° 34' 59" N  36° 38' 59" W — F12-05 recovery 22.09.2206
Current meters63° 21' 59" N  35° 3' 59" W — G1-05 recovery 22.09.2006
Current profiler (eg ADCP)63° 0' 59" N  40° 30' 59" W — ADCP deployed 25.09.2006
Other physical oceanographic measurements63° 0' 0" N  40° 32' 59" W — TUBE-28 deployed 23.09.2006
Other physical oceanographic measurements63° 0' 59" N  39° 38' 59" W — Glider deployed 25.09.2006
Geology and geophysics 
Bottom photography64° 39' 59" N  23° 13' 59" W — ROV - Test